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  • richardmitnick 7:39 am on September 12, 2020 Permalink | Reply
    Tags: "High-fidelity record of Earth’s climate history puts current changes in context", , , , For the first time climate scientists have compiled a continuous high-fidelity record of variations in Earth’s climate extending 66 million years into the past., Geophysics, Greenhouse gas emissions and other human activities are now driving the planet toward the Warmhouse and Hothouse climate states not seen since the Eocene epoch., The climate shows rhythmic variations corresponding to changes in Earth’s orbit around the sun., The new climate record provides a valuable framework for many areas of research., The record reveals four distinctive climate states which the researchers dubbed Hothouse; Warmhouse; Coolhouse; and Icehouse.,   

    From UC Santa Cruz: “High-fidelity record of Earth’s climate history puts current changes in context” 


    From UC Santa Cruz

    September 10, 2020
    Tim Stephens
    stephens@ucsc.edu

    A continuous record of the past 66 million years shows natural climate variability due to changes in Earth’s orbit around the sun is much smaller than projected future warming due to greenhouse gas emissions.

    1

    For the first time, climate scientists have compiled a continuous, high-fidelity record of variations in Earth’s climate extending 66 million years into the past. The record reveals four distinctive climate states, which the researchers dubbed Hothouse, Warmhouse, Coolhouse, and Icehouse.

    These major climate states persisted for millions and sometimes tens of millions of years, and within each one the climate shows rhythmic variations corresponding to changes in Earth’s orbit around the sun. But each climate state has a distinctive response to orbital variations, which drive relatively small changes in global temperatures compared with the dramatic shifts between different climate states.

    The new findings, published September 10 in Science, are the result of decades of work and a large international collaboration. The challenge was to determine past climate variations on a time scale fine enough to see the variability attributable to orbital variations (in the eccentricity of Earth’s orbit around the sun and the precession and tilt of its rotational axis).

    “We’ve known for a long time that the glacial-interglacial cycles are paced by changes in Earth’s orbit, which alter the amount of solar energy reaching Earth’s surface, and astronomers have been computing these orbital variations back in time,” explained coauthor James Zachos, distinguished professor of Earth and planetary sciences and Ida Benson Lynn Professor of Ocean Health at UC Santa Cruz.

    “As we reconstructed past climates, we could see long-term coarse changes quite well. We also knew there should be finer-scale rhythmic variability due to orbital variations, but for a long time it was considered impossible to recover that signal,” Zachos said. “Now that we have succeeded in capturing the natural climate variability, we can see that the projected anthropogenic warming will be much greater than that.”

    Icehouse

    For the past 3 million years, Earth’s climate has been in an Icehouse state characterized by alternating glacial and interglacial periods. Modern humans evolved during this time, but greenhouse gas emissions and other human activities are now driving the planet toward the Warmhouse and Hothouse climate states not seen since the Eocene epoch, which ended about 34 million years ago. During the early Eocene, there were no polar ice caps, and average global temperatures were 9 to 14 degrees Celsius higher than today.

    “The IPCC projections for 2300 in the ‘business-as-usual’ scenario will potentially bring global temperature to a level the planet has not seen in 50 million years,” Zachos said.

    Critical to compiling the new climate record was getting high-quality sediment cores from deep ocean basins through the international Ocean Drilling Program (ODP, later the Integrated Ocean Drilling Program, IODP, succeeded in 2013 by the International Ocean Discovery Program). Signatures of past climates are recorded in the shells of microscopic plankton (called foraminifera) preserved in the seafloor sediments. After analyzing the sediment cores, researchers then had to develop an “astrochronology” by matching the climate variations recorded in sediment layers with variations in Earth’s orbit (known as Milankovitch cycles).

    “The community figured out how to extend this strategy to older time intervals in the mid-1990s,” said Zachos, who led a study published in 2001 in Science that showed the climate response to orbital variations for a 5-million-year period covering the transition from the Oligocene epoch to the Miocene, about 25 million years ago.

    “That changed everything, because if we could do that, we knew we could go all the way back to maybe 66 million years ago and put these transient events and major transitions in Earth’s climate in the context of orbital-scale variations,” he said.

    Sediment cores

    Zachos has collaborated for years with lead author Thomas Westerhold at the University of Bremen Center for Marine Environmental Sciences (MARUM) in Germany, which houses a vast repository of sediment cores. The Bremen lab along with Zachos’s group at UCSC generated much of the new data for the older part of the record.

    Westerhold oversaw a critical step, splicing together overlapping segments of the climate record obtained from sediment cores from different parts of the world. “It’s a tedious process to assemble this long megasplice of climate records, and we also wanted to replicate the records with separate sediment cores to verify the signals, so this was a big effort of the international community working together,” Zachos said.

    Now that they have compiled a continuous, astronomically dated climate record of the past 66 million years, the researchers can see that the climate’s response to orbital variations depends on factors such as greenhouse gas levels and the extent of polar ice sheets.

    “In an extreme greenhouse world with no ice, there won’t be any feedbacks involving the ice sheets, and that changes the dynamics of the climate,” Zachos explained.

    Greenhouse gas levels

    Most of the major climate transitions in the past 66 million years have been associated with changes in greenhouse gas levels. Zachos has done extensive research on the Paleocene-Eocene Thermal Maximum (PETM), for example, showing that this episode of rapid global warming, which drove the climate into a Hothouse state, was associated with a massive release of carbon into the atmosphere. Similarly, in the late Eocene, as atmospheric carbon dioxide levels were dropping, ice sheets began to form in Antarctica and the climate transitioned to a Coolhouse state.

    “The climate can become unstable when it’s nearing one of these transitions, and we see more deterministic responses to orbital forcing, so that’s something we would like to better understand,” Zachos said.

    The new climate record provides a valuable framework for many areas of research, he added. It is not only useful for testing climate models, but also for geophysicists studying different aspects of Earth dynamics and paleontologists studying how changing environments drive the evolution of species.

    “It’s a significant advance in Earth science, and a major legacy of the international Ocean Drilling Program,” Zachos said.

    Coauthors Steven Bohaty, now at the University of Southampton, and Kate Littler, now at the University of Exeter, both worked with Zachos at UC Santa Cruz. The paper’s coauthors also include researchers at more than a dozen institutions around the world. This work was funded by the German Research Foundation (DFG), Natural Environmental Research Council (NERC), European Union’s Horizon 2020 program, National Science Foundation of China, Netherlands Earth System Science Centre, and the U.S. National Science Foundation.

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    UCSC Lick Observatory, Mt Hamilton, in San Jose, California, Altitude 1,283 m (4,209 ft).

    UC Observatories Lick Autmated Planet Finder, fully robotic 2.4-meter optical telescope at Lick Observatory, situated on the summit of Mount Hamilton, east of San Jose, California, USA.

    The UCO Lick C. Donald Shane telescope is a 120-inch (3.0-meter) reflecting telescope located at the Lick Observatory, Mt Hamilton, in San Jose, California, Altitude 1,283 m (4,209 ft).

    UC Santa Cruz campus

    The University of California, Santa Cruz, opened in 1965 and grew, one college at a time, to its current (2008-09) enrollment of more than 16,000 students. Undergraduates pursue more than 60 majors supervised by divisional deans of humanities, physical & biological sciences, social sciences, and arts. Graduate students work toward graduate certificates, master’s degrees, or doctoral degrees in more than 30 academic fields under the supervision of the divisional and graduate deans. The dean of the Jack Baskin School of Engineering oversees the campus’s undergraduate and graduate engineering programs.

    UCSC is the home base for the Lick Observatory.

    Lick Observatory’s 36-inch Great Great Refractor telescope housed in the South (large) Dome of main building.

    Search for extraterrestrial intelligence expands at Lick Observatory
    New instrument scans the sky for pulses of infrared light
    March 23, 2015
    By Hilary Lebow
    1
    The NIROSETI instrument saw first light on the Nickel 1-meter Telescope at Lick Observatory on March 15, 2015. (Photo by Laurie Hatch) UCSC Lick Nickel telescope

    Astronomers are expanding the search for extraterrestrial intelligence into a new realm with detectors tuned to infrared light at UC’s Lick Observatory. A new instrument, called NIROSETI, will soon scour the sky for messages from other worlds.

    “Infrared light would be an excellent means of interstellar communication,” said Shelley Wright, an assistant professor of physics at UC San Diego who led the development of the new instrument while at the University of Toronto’s Dunlap Institute for Astronomy & Astrophysics.

    Wright worked on an earlier SETI project at Lick Observatory as a UC Santa Cruz undergraduate, when she built an optical instrument designed by UC Berkeley researchers. The infrared project takes advantage of new technology not available for that first optical search.

    Infrared light would be a good way for extraterrestrials to get our attention here on Earth, since pulses from a powerful infrared laser could outshine a star, if only for a billionth of a second. Interstellar gas and dust is almost transparent to near infrared, so these signals can be seen from great distances. It also takes less energy to send information using infrared signals than with visible light.

    Frank Drake, professor emeritus of astronomy and astrophysics at UC Santa Cruz and director emeritus of the SETI Institute, said there are several additional advantages to a search in the infrared realm.

    “The signals are so strong that we only need a small telescope to receive them. Smaller telescopes can offer more observational time, and that is good because we need to search many stars for a chance of success,” said Drake.

    The only downside is that extraterrestrials would need to be transmitting their signals in our direction, Drake said, though he sees this as a positive side to that limitation. “If we get a signal from someone who’s aiming for us, it could mean there’s altruism in the universe. I like that idea. If they want to be friendly, that’s who we will find.”

    Scientists have searched the skies for radio signals for more than 50 years and expanded their search into the optical realm more than a decade ago. The idea of searching in the infrared is not a new one, but instruments capable of capturing pulses of infrared light only recently became available.

    “We had to wait,” Wright said. “I spent eight years waiting and watching as new technology emerged.”

    Now that technology has caught up, the search will extend to stars thousands of light years away, rather than just hundreds. NIROSETI, or Near-Infrared Optical Search for Extraterrestrial Intelligence, could also uncover new information about the physical universe.

    “This is the first time Earthlings have looked at the universe at infrared wavelengths with nanosecond time scales,” said Dan Werthimer, UC Berkeley SETI Project Director. “The instrument could discover new astrophysical phenomena, or perhaps answer the question of whether we are alone.”

    NIROSETI will also gather more information than previous optical detectors by recording levels of light over time so that patterns can be analyzed for potential signs of other civilizations.

    “Searching for intelligent life in the universe is both thrilling and somewhat unorthodox,” said Claire Max, director of UC Observatories and professor of astronomy and astrophysics at UC Santa Cruz. “Lick Observatory has already been the site of several previous SETI searches, so this is a very exciting addition to the current research taking place.”

    NIROSETI will be fully operational by early summer and will scan the skies several times a week on the Nickel 1-meter telescope at Lick Observatory, located on Mt. Hamilton east of San Jose.

    The NIROSETI team also includes Geoffrey Marcy and Andrew Siemion from UC Berkeley; Patrick Dorval, a Dunlap undergraduate, and Elliot Meyer, a Dunlap graduate student; and Richard Treffers of Starman Systems. Funding for the project comes from the generous support of Bill and Susan Bloomfield.

     
  • richardmitnick 5:17 pm on August 24, 2020 Permalink | Reply
    Tags: , , At least twice in Earth’s history nearly the entire planet was encased in a sheet of snow and ice., , Geophysics, , The findings may also apply to the search for life on other planets.   

    From MIT News: “Study: A plunge in incoming sunlight may have triggered ‘Snowball Earths'” 

    MIT News

    From MIT News

    July 29, 2020
    Jennifer Chu

    1
    The trigger for “Snowball Earth” global ice ages may have been drops in incoming sunlight that happened quickly, in geological terms, according to an MIT study. Credits: Image: Wikimedia, Oleg Kuznetsov

    At least twice in Earth’s history, nearly the entire planet was encased in a sheet of snow and ice. These dramatic “Snowball Earth” events occurred in quick succession, somewhere around 700 million years ago, and evidence suggests that the consecutive global ice ages set the stage for the subsequent explosion of complex, multicellular life on Earth.

    Scientists have considered multiple scenarios for what may have tipped the planet into each ice age. While no single driving process has been identified, it’s assumed that whatever triggered the temporary freeze-overs must have done so in a way that pushed the planet past a critical threshold, such as reducing incoming sunlight or atmospheric carbon dioxide to levels low enough to set off a global expansion of ice.

    But MIT scientists now say that Snowball Earths were likely the product of “rate-induced glaciations.” That is, they found the Earth can be tipped into a global ice age when the level of solar radiation it receives changes quickly over a geologically short period of time. The amount of solar radiation doesn’t have to drop to a particular threshold point; as long as the decrease in incoming sunlight occurs faster than a critical rate, a temporary glaciation, or Snowball Earth, will follow.

    These findings, published today in the Proceedings of the Royal Society A, suggest that whatever triggered the Earth’s ice ages most likely involved processes that quickly reduced the amount of solar radiation coming to the surface, such as widespread volcanic eruptions or biologically induced cloud formation that could have significantly blocked out the sun’s rays.

    The findings may also apply to the search for life on other planets. Researchers have been keen on finding exoplanets within the habitable zone — a distance from their star that would be within a temperature range that could support life. The new study suggests that these planets, like Earth, could also ice over temporarily if their climate changes abruptly. Even if they lie within a habitable zone, Earth-like planets may be more susceptible to global ice ages than previously thought.

    “You could have a planet that stays well within the classical habitable zone, but if incoming sunlight changes too fast, you could get a Snowball Earth,” says lead author Constantin Arnscheidt, a graduate student in MIT’s Department of Earth, Atmospheric and Planetary Sciences (EAPS). “What this highlights is the notion that there’s so much more nuance in the concept of habitability.”

    Arnscheidt has co-authored the paper with Daniel Rothman, EAPS professor of geophysics, and co-founder and co-director of the Lorenz Center.

    A runaway snowball

    Regardless of the particular processes that triggered past glaciations, scientists generally agree that Snowball Earths arose from a “runaway” effect involving an ice-albedo feedback: As incoming sunlight is reduced, ice expands from the poles to the equator. As more ice covers the globe, the planet becomes more reflective, or higher in albedo, which further cools the surface for more ice to expand. Eventually, if the ice reaches a certain extent, this becomes a runaway process, resulting in a global glaciation.

    Global ice ages on Earth are temporary in nature, due to the planet’s carbon cycle. When the planet is not covered in ice, levels of carbon dioxide in the atmosphere are somewhat controlled by the weathering of rocks and minerals. When the planet is covered in ice, weathering is vastly reduced, so that carbon dioxide builds up in the atmosphere, creating a greenhouse effect that eventually thaws the planet out of its ice age.

    Scientists generally agree that the formation of Snowball Earths has something to do with the balance between incoming sunlight, the ice-albedo feedback, and the global carbon cycle.

    “There are lots of ideas for what caused these global glaciations, but they all really boil down to some implicit modification of solar radiation coming in,” Arnscheidt says. “But generally it’s been studied in the context of crossing a threshold.”

    He and Rothman had previously studied other periods in Earth’s history where the speed, or rate at which certain changes in climate occurred had a role in triggering events, such as past mass extinctions.

    “In the course of this exercise, we realized there was an immediate way to make a serious point by applying such ideas of rate-induced tipping, to Snowball Earth and habitability,” Rothman says.

    “Be wary of speed”

    The researchers developed a simple mathematical model of the Earth’s climate system that includes equations to represent relations between incoming and outgoing solar radiation, the surface temperature of the Earth, the concentration of carbon dioxide in the atmosphere, and the effects of weathering in taking up and storing atmospheric carbon dioxide. The researchers were able to tune each of these parameters to observe which conditions generated a Snowball Earth.

    Ultimately, they found that a planet was more likely to freeze over if incoming solar radiation decreased quickly, at a rate that was faster than a critical rate, rather than to a critical threshold, or particular level of sunlight. There is some uncertainty in exactly what that critical rate would be, as the model is a simplified representation of the Earth’s climate. Nevertheless, Arnscheidt estimates that the Earth would have to experience about a 2 percent drop in incoming sunlight over a period of about 10,000 years to tip into a global ice age.

    “It’s reasonable to assume past glaciations were induced by geologically quick changes to solar radiation,” Arnscheidt says.

    The particular mechanisms that may have quickly darkened the skies over tens of thousands of years is still up for debate. One possibility is that widespread volcanoes may have spewed aerosols into the atmosphere, blocking incoming sunlight around the world. Another is that primitive algae may have evolved mechanisms that facilitated the formation of light-reflecting clouds. The results from this new study suggest scientists may consider processes such as these, that quickly reduce incoming solar radiation, as more likely triggers for Earth’s ice ages.

    “Even though humanity will not trigger a snowball glaciation on our current climate trajectory, the existence of such a ‘rate-induced tipping point’ at the global scale may still remain a cause for concern,” Arnscheidt points out. “For example, it teaches us that we should be wary of the speed at which we are modifying Earth’s climate, not just the magnitude of the change. There could be other such rate-induced tipping points that might be triggered by anthropogenic warming. Identifying these and constraining their critical rates is a worthwhile goal for further research.”

    See the full article here .


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    Please help promote STEM in your local schools.


    Stem Education Coalition

    MIT Seal

    The mission of MIT is to advance knowledge and educate students in science, technology, and other areas of scholarship that will best serve the nation and the world in the twenty-first century. We seek to develop in each member of the MIT community the ability and passion to work wisely, creatively, and effectively for the betterment of humankind.

    MIT Campus

     
  • richardmitnick 9:20 am on July 4, 2020 Permalink | Reply
    Tags: "Geologists Identify Deep-Earth Structures That May Signal Hidden Metal Lodes", , , , , , Geophysics, The mining of metals needed to create a vast infrastructure for renewable power generation; storage; transmission and usage., The new study started in 2016 in Australia where much of the world’s lead zinc and copper is mined., The scientists’ map shows such zones looping through all the continents., The study’s authors found that the richest Australian mines lay neatly along the line where thick old lithosphere grades out to 170 kilometers as it approaches the coast.   

    From Columbia University – State of the Planet: “Geologists Identify Deep-Earth Structures That May Signal Hidden Metal Lodes” 

    Columbia U bloc

    From Columbia University – State of the Planet

    June 30, 2020
    Kevin Krajick

    Finding New Giant Copper, Lead, Zinc Deposits Will Fuel Green Infrastructure.

    If the world is to maintain a sustainable economy and fend off the worst effects of climate change, at least one industry will soon have to ramp up dramatically: the mining of metals needed to create a vast infrastructure for renewable power generation, storage, transmission and usage. The problem is, demand for such metals is likely to far outstrip currently both known deposits and the existing technology used to find more ore bodies.

    Now, in a new study, scientists have discovered previously unrecognized structural lines 100 miles or more down in the earth that appear to signal the locations of giant deposits of copper, lead, zinc and other vital metals lying close enough to the surface to be mined, but too far down to be found using current exploration methods. The discovery could greatly narrow down search areas, and reduce the footprint of future mines, the authors say. The study appears this week in the journal Nature Geoscience.

    “We can’t get away from these metals—they’re in everything, and we’re not going to recycle everything that was ever made,” said lead author Mark Hoggard, a postdoctoral researcher at Harvard University and Columbia University’s Lamont-Doherty Earth Observatory. “There’s a real need for alternative sources.”

    1
    A new study shows that giant ore deposits are tightly distributed above where rigid rocks that comprise the nuclei of ancient continents begin to thin, far below the surface (white areas). Redder areas indicate the thinnest rocks beyond the boundary; bluer ones, the thickest. Circles, triangles and squares show known large sediment-hosted deposits of different metals. (Adapted from Hoggard et al., Nature Geoscience, 2020)

    The study found that 85 percent of all known base-metal deposits hosted in sediments—and 100 percent of all “giant” deposits (those holding more than 10 million tons of metal)—lie above deeply buried lines girdling the planet that mark the edges of ancient continents. Specifically, the deposits lie along boundaries where the earth’s lithosphere—the rigid outermost cladding of the planet, comprising the crust and upper mantle—thins out to about 170 kilometers below the surface.

    Up to now, all such deposits have been found pretty much at the surface, and their locations have seemed to be somewhat random. Most discoveries have been made basically by geologists combing the ground and whacking at rocks with hammers. Geophysical exploration methods using gravity and other parameters to find buried ore bodies have entered in recent decades, but the results have been underwhelming. The new study presents geologists with a new, high-tech treasure map telling them where to look.

    Due to the demands of modern technology and the growth of populations and economies, the need for base metals in the next 25 years is projected to outpace all the base metals so far mined in human history. Copper is used in basically all electronics wiring, from cell phones to generators; lead for photovoltaic cells, high-voltage cables, batteries and super capacitors; and zinc for batteries, as well as fertilizers in regions where it is a limiting factor in soils, including much of China and India. Many base-metal mines also yield rarer needed elements, including cobalt, iridium and molybdenum. One recent study suggests that in order to develop a sustainable global economy, between 2015 and 2050 electric passenger vehicles must increase from 1.2 million to 1 billion; battery capacity from 0.5 gigawatt hours to 12,000; and photovoltaic capacity from 223 gigawatts to more than 7,000.

    The new study started in 2016 in Australia, where much of the world’s lead, zinc and copper is mined. The government funded work to see whether mines in the northern part of the continent had anything in common. It built on the fact that in recent years, scientists around the world have been using seismic waves to map the highly variable depth of the lithosphere, which ranges down to 300 kilometers in the nuclei of the most ancient, undisturbed continental masses, and tapers to near zero under the younger rocks of the ocean floors. As continents have shifted, collided and rifted over many eons, their subsurfaces have developed scar-like lithospheric irregularities, many of which have now been mapped.

    The study’s authors found that the richest Australian mines lay neatly along the line where thick, old lithosphere grades out to 170 kilometers as it approaches the coast. They then expanded their investigation to some 2,100 sediment-hosted mines across the world, and found an identical pattern. Some of the 170-kilometer boundaries lie near current coastlines, but many are nestled deep within the continents, having formed at various points in the distant past when the continents had different shapes. Some are up to 2 billion years old.

    The scientists’ map shows such zones looping through all the continents, including areas in western Canada; the coasts of Australia, Greenland and Antarctica; the western, southeastern and Great Lakes regions of the United States; and much of the Amazon, northwest and southern Africa, northern India and central Asia. While some of the identified areas already host enormous mines, others are complete blanks on the mining map.

    The authors believe that the metal deposits formed when thick continental rocks stretched out and sagged to form a depression, like a wad of gum pulled apart. This thinned the lithosphere and allowed seawater to flood in. Over long periods, these watery low spots got filled in with metal-bearing sediments from adjoining, higher-elevation rocks. Salty water then circulated downward until reaching depths where chemical and temperature conditions were just right for metals picked up by the water in deep parts of the basin to precipitate out to form giant deposits, anywhere from 100 meters to 10 kilometers below the then-surface. The key ingredient was the depth of the lithosphere. Where it is thickest, little heat from the hot lower mantle rises to potential near-surface ore-forming zones, and where it is thinnest, a lot of heat gets through. The 170-kilometer boundary seems to be Goldilocks zone for creating just the right temperature conditions, as long as the right chemistry also is present.

    “It really just hits the sweet spot,” said Hoggard. “These deposits contain lots of metal bound up in high-grade ores, so once you find something like this, you only have to dig one hole.” Most current base-metal mines are sprawling, destructive open-pit operations. But in many cases, deposits starting as far down as a kilometer could probably be mined economically, and these would “almost certainly be taken out via much less disruptive shafts,” said Hoggard.

    The study promises to open exploration in so far poorly explored areas, including parts of Australia, central Asia and western Africa. Based on a preliminary report of the new study that the authors presented at an academic conference last year, a few companies appear to have already claimed ground in Australia and North America. But the mining industry is notoriously secretive, so it is not clear yet how widespread such activity might be.

    “This is a truly profound finding and is the first time anyone has suggested that mineral deposits formed in sedimentary basins … at depths of only kilometers in the crust were being controlled by forces at depths of hundreds of kilometers at the base of the lithosphere,” said a report in Mining Journal reviewing the preliminary presentation last year.

    The study’s other authors are Karol Czarnota of Geoscience Australia, who led the initial Australian mapping project; Fred Richards of Harvard University and Imperial College London; David Huston of Geoscience Australia; and A. Lynton Jaques and Sia Ghelichkhan of Australian National University.

    Hoggard has put the study into a global context on his website.

    See the full article here .

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    Columbia University was founded in 1754 as King’s College by royal charter of King George II of England. It is the oldest institution of higher learning in the state of New York and the fifth oldest in the United States.

     
  • richardmitnick 12:44 pm on February 6, 2020 Permalink | Reply
    Tags: "Looking to mud to study how particles become sticky", , Fluids mechanics, Geophysics, ,   

    From Penn Today: “Looking to mud to study how particles become sticky” 


    From Penn Today

    February 5, 2020
    Katherine Unger Baillie

    A collaboration of geophysicists and fluids mechanics experts led to a fundamental new insight into how tiny ‘bridges’ help particles of all kinds form aggregates.

    1
    Using a model system of glass particles, researchers from Penn found “solid bridges” formed by smaller-size particles between larger ones. The same bridges were present in suspensions of clay, a common component of natural soils. These structures provided stability, the team found, even when a moving channel of water threatened to wash the particle clumps away. (Video: Jerolmack laboratory)

    2
    Tiny ‘bridges’ help particles stick together. Credit: CC0 Public Domain

    It happens outside every time it rains: The soil gets wet and may form sticky mud. Then it dries. Later it might rain again. Each wetting and rewetting affects the structure and stability of the soil. These changes are taken into account when, for example, architects and engineers design, site, and construct buildings. But more broadly, the science of how particles stick together and then pull apart touches fields as diverse as natural hazards, crop fertilization, cement production, and pharmaceutical design.

    Uniting these disparate fields, a team at the University of Pennsylvania has found that when particles are wet and then allowed to dry, the size of those particles has a lot to do with how strongly they stick together and whether they stay together or fall apart the next time they are wetted.

    What lends these sticky aggregates strength, the team found, are thin bridges formed when particles of the material are suspended in a liquid and then left to dry, leaving thin strands of particles that connect larger clumps. The strands, which the researchers call solid bridges, increase the aggregates’ stability 10- to 100-fold.

    The researchers reported their findings in the journal Proceedings of the National Academy of Sciences.

    “This solid bridging phenomenon may be ubiquitous and important in understanding the strength and erodibility of natural soils,” says Paulo Arratia, a fluid mechanics engineer in Penn’s School of Engineering and Applied Science and a coauthor on the study.

    “We found that a particle’s size can outweigh the contribution of its chemical properties when it comes to determining how strongly it sticks to other particles,” says Douglas Jerolmack, a geophysicist in the School of Arts and Sciences and the paper’s corresponding author.

    The research team was led by Ali Seiphoori, formerly a postdoc in Jerolmack’s lab and now at the Massachusetts Institute of Technology, and included physics postdoc Xiao-guang Ma. The current work developed from investigations they had been pursuing in conjunction with Penn’s Perelman School of Medicine on asbestos, specifically how its needle-like fibers stick to one other and to other materials to form aggregates. That got them thinking more generally about what determines the strength and stability of an aggregate.

    The group took an experimental approach to answering this question by creating a simple model of particle aggregation. They suspended glass spheres of two sizes, 3 microns and 20 microns, in a droplet of water. (For reference, a human hair is roughly 50 to 100 microns in width.) As the water evaporated, the edges of the droplet retreated, dragging the particles inward. Eventually the shrinking water droplet transformed into multiple smaller droplets connected by a thin water bridge, known as a capillary bridge, before that, too, evaporated.

    The team found that the extreme suction pressures caused by evaporation pulled the small particles so tightly together that they fused together in the capillary bridges, leaving behind solid bridges between the larger particles, to which they also bound, once the water evaporated completely.

    When the team rewet the particles, applying water in a controlled flow, they found that aggregates composed solely of the 20-micron particles were much easier to disrupt and resuspend than those composed of either the smaller particles, or mixtures of small and larger particles.

    “We found that if aggregates composed of only particles larger than 5 microns were rewet, they collapsed,” Jerolmack says. “But under 5 microns, nothing happens, the aggregates were stable.”

    In further tests with mixtures of particles of five different sizes—more closely mimicking natural soil composition—the researchers found the same bridging effect at different scales. The largest particles were bridged by the second largest, which were in turn bridged by the third largest, and so on. Even mixtures that contained only a small fraction of smaller particles became more stable thanks to solid bridging.

    How much more stable? To find out, Seiphoori painstakingly glued the probe of an atomic-force microscope to a single particle, let it set, and then quantified the “pull-off force” required to remove that particle from the aggregate. Repeating this for particles in aggregates of both big and small particles, they found that particles were 10 to 100 times harder to pull off when they had formed a solid bridge structure than in other configurations.

    To convince themselves that the same would be true with materials besides their experimental glass beads, they performed similar experiments using two types of clay that are both common components of natural soils. The principals held; the smaller clay particles and the presence of solid bridges made aggregates stable. And the reverse was also true. When clay particles smaller than 5 microns were removed from the suspensions, their resulting aggregates lost cohesion.

    “Clay soils are thought to be fundamentally cohesive,” says Jerolmack, “and that cohesiveness has usually been attributed to their charge or some other mineralogic property. But we found this very surprising thing that it doesn’t seem to be the fundamental properties of clay that make it sticky but rather the fact that clay particles tend to be very small. It’s a brand-new explanation for cohesion.”

    These new insights about the contribution of particle size to aggregate stability open up new possibilities for considering how to enhance stability of materials like soil or cement when desired. “You could envision stabilizing soils before a construction project by adding smaller particles that help bind the soil together,” Jerolmack says.

    In addition, the production of a variety of materials, from medical devices to LED screen coatings, relies on thin film deposition, which the researchers say might benefit from the controlled production of aggregates that they observed in their experiments.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    U Penn campus

    Academic life at Penn is unparalleled, with 100 countries and every U.S. state represented in one of the Ivy League’s most diverse student bodies. Consistently ranked among the top 10 universities in the country, Penn enrolls 10,000 undergraduate students and welcomes an additional 10,000 students to our world-renowned graduate and professional schools.

    Penn’s award-winning educators and scholars encourage students to pursue inquiry and discovery, follow their passions, and address the world’s most challenging problems through an interdisciplinary approach.

     
  • richardmitnick 10:57 am on February 1, 2020 Permalink | Reply
    Tags: , , Geologist Melodie French, , Geophysics, ,   

    From Rice University: Women in STEM-“Fed grant backs Rice earthquake research” Geologist Melodie French 

    Rice U bloc

    From Rice University

    January 31, 2020

    Jeff Falk
    713-348-6775
    jfalk@rice.edu

    Mike Williams
    713-348-6728
    mikewilliams@rice.edu

    Geologist Melodie French wins National Science Foundation CAREER Award.

    1
    Rice University geologist Melodie French has earned a National Science Foundation CAREER Award to support her investigation of the tectonic roots of earthquakes and tsunamis. Photo by Jeff Fitlow.

    The tectonic plates of the world were mapped in 1996, USGS.

    Rice University geologist Melodie French is crushing it in her quest to understand the physics responsible for earthquakes.

    The assistant professor of Earth, environmental and planetary science has earned a prestigious CAREER Award, a five-year National Science Foundation (NSF) grant for $600,000 to support her investigation of the tectonic roots of earthquakes and tsunamis.

    CAREER awards support the research and educational development of young scholars likely to become leaders in their fields. The grants, among the most competitive awarded by the NSF, go to fewer than 400 scholars each year across all disciplines.

    For French, the award gives her Rice lab the opportunity to study rocks exhumed from subduction zones at plate boundaries that are often the source of megathrust earthquakes and tsunamis. Her lab squeezes rock samples to characterize the strength of the rocks deep underground where the plates meet.

    “Fundamentally, we hope to learn how the material properties of the rocks themselves control where earthquakes happen, how big one might become, what causes an earthquake to sometimes arrest after only a small amount of slip or what allows some to grow quite large,” French said.

    “A lot of geophysics involves putting out instruments to see signals that propagate to the Earth’s surface,” she said. “But we try to understand the properties of the rocks that allow these different phenomena to happen.”

    That generally involves putting rocks under extreme stress. “We squish rocks at different temperatures and pressures and at different rates while measuring force and strain in as many dimensions as we can,” French said. “That gives us a full picture of how the rocks deform under different conditions.”

    The lab conducts experiments on both exposed surface rocks that were once deep within subduction zones and rock acquired by drilling for core samples.

    2
    Rice University geologist Melodie French and graduate student Ben Belzer work with a rock sample. French has been granted a National Science Foundation CAREER Award to study the tectonic roots of earthquakes and tsunamis. Photo by Jeff Fitlow.

    I’m working with (Rice Professor) Juli Morgan on a subduction zone off of New Zealand where they drilled through part of the fault zone and brought rock up from about 500 meters deep,” French said. “But many big earthquakes happen much deeper than we could ever drill. So we need to go into the field to find ancient subduction rocks that have somehow managed to come to the surface.”

    French is not sure if it will ever be possible to accurately predict earthquakes. “But one thing we can do is create better hazard maps to help us understand what regions should be prepared for quakes,” she said.

    French is a native of Maine who earned her bachelor’s degree at Oberlin College, a master’s at the University of Wisconsin-Madison and a Ph.D. at Texas A&M University.

    The award, co-funded by the NSF’s Geophysics, Tectonics and Marine Geology and Geophysics programs, will also provide inquiry-based educational opportunities in scientific instrument design and use to K-12 students as well as undergraduate and graduate-level students.

    3
    Geologist Melodie French sets up an experiment in her Rice University lab. She has won a National Science Foundation CAREER Award, a prestigious grant given to young scholars likely to become leaders in their fields. (Credit: Jeff Fitlow/Rice University)

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings


    Stem Education Coalition

    Rice U campus

    In his 1912 inaugural address, Rice University president Edgar Odell Lovett set forth an ambitious vision for a great research university in Houston, Texas; one dedicated to excellence across the range of human endeavor. With this bold beginning in mind, and with Rice’s centennial approaching, it is time to ask again what we aspire to in a dynamic and shrinking world in which education and the production of knowledge will play an even greater role. What shall our vision be for Rice as we prepare for its second century, and how ought we to advance over the next decade?

    This was the fundamental question posed in the Call to Conversation, a document released to the Rice community in summer 2005. The Call to Conversation asked us to reexamine many aspects of our enterprise, from our fundamental mission and aspirations to the manner in which we define and achieve excellence. It identified the pressures of a constantly changing and increasingly competitive landscape; it asked us to assess honestly Rice’s comparative strengths and weaknesses; and it called on us to define strategic priorities for the future, an effort that will be a focus of the next phase of this process.

     
  • richardmitnick 12:25 pm on May 28, 2019 Permalink | Reply
    Tags: "John Hernlund - Looking deep for answers to the origins of life", , , , , , ELSI-Tokyo Tech's Earth-Life Science Institute, Geophysics, In the 20th century science took a more focused approach and drilled very deep and also very narrow.,   

    From Tokyo Institute of Technology: “John Hernlund – Looking deep for answers to the origins of life” 

    tokyo-tech-bloc

    From Tokyo Institute of Technology

    5.28.19

    1
    Professor and Vice DirectorJohn Hernlund, Earth-Life Science Institute
    As Tokyo Tech’s Earth-Life Science Institute (ELSI) has evolved, it has needed senior scientists to lead research in key areas, managers to help run the institute, recruiters to search out prospective researchers and students around the world, educators to serve as advisor to doctoral students, and a friend to invite its many visitors from abroad home for dinner. Almost since ELSI began, John Hernlund has been doing all this and much more. A tenured Tokyo Tech professor, he is a passionate advocate for ELSI as well as a top scientist in his deep Earth field.

    You are a geophysicist, and you model the dynamics of the interior of the Earth. What makes your science relevant to an origins of life institute like ELSI?

    At ELSI we’re very interested in understanding the origin of the planet and how it gave rise to life. All of our current theories, all the evidence, suggests that life started more than 3.8 billion years ago. Unfortunately, we don’t have many rocks that are this old to study. So answers to lots of questions about what the early Earth was like, how was it formed, how did it give rise to the environment that created life, are buried deep inside the planet. It’s like going to the Grand Canyon and seeing all the layers of the Earth as you go deeper and deeper, each one from further back in time.

    Life is very old and has been evolving as a part of many systems that are all connected with each other — like plate tectonics, the composition of the atmosphere, the planet’s core that makes the magnetic field. It’s an open system. As living things, we eat matter which becomes incorporated in our bodies, and then we get rid of it. So we’re actually not a thing, we’re a process. We have to understand how the entire planet collaborates to make something like life possible and how then life evolves over time as the planet changes and how the systems interact with each other. These are the great questions of all of natural science. And we have to understand what is happening underneath our feet to be able to address all of them.

    This kind of systems thinking is very important at ELSI. Why is that?

    In the 20th century, science took a more focused approach and drilled very deep and also very narrow. It made many breakthroughs this way. But the big questions — like how life came to be on Earth, or is life possible elsewhere in the universe and if so, how would it happen and where should we look — these are questions you can’t find the answers to by drilling deep and narrow. You have to put things together and look at the larger picture.

    3
    Life exists on Earth because of its unique environment. ELSI researchers work to (A) determine the structure of the Earth, (B) identify the kind of life that first appeared and when its birth took place, and (C) investigate how those early life forms evolved, through multiple perspectives and procedures. Then, by applying those discoveries on genetic information of primitive life forms, they aim to further explore (D) “whether life would arise in environments entirely different from Earth.”

    Do any of your own recent findings show these connections?

    Some work that made a really big impact on ELSI involves the origin of the magnetic field in the Earth. It connects life on the surface to processes happening very deep beneath our feet in the metallic core where we think that convection currents are responsible for producing the magnetic field by dynamo action1. Heat lost from the deep interior of the planet to the surface drives convection flow and overturn of both the rocky mantle and the liquid metal core inside the Earth, much like the convection you can see in a bowl of hot miso soup as it cools down. Of course the rock moves very slowly, at speeds of roughly centimeters per year, while the liquid core currents move at about 0.1 millimeters per second. In my research I use quantitative models to study the connection between material properties at extreme conditions, heat loss from the interior, chemical cycling, and sustenance of deep magnetism.

    What we’ve been able to do — with a collaboration of theory and experiments — is to open the question of how did the core cool down, what did the initial temperature have to be, and what was the chemical composition in order to have conditions necessary to have an ancient magnetic field. We see in biology that some very ancient forms of life used magnetism. For example, “magnetotactic” bacteria produce magnetite crystals inside themselves, which helps them orient along the magnetic lines. And in the local environment this means they could go find more or less sunlight, more or less oxygen, different nutrients. It was a very ancient form of eyesight, based on magnetism coming from the core.

    4
    Illustration of bridgmanite-enriched ancient mantle structures (BEAMS), a model proposed by Hernlund and colleagues describing how large-scale silica-enriched highly viscous regions stabilize and organize the pattern of convection in the lower mantle. (Ballmer et al. “Persistence of strong silica-enriched domains in the Earth’s lower mantle.” Nature Geoscience 10, no. 3 (2017): 236.)

    You were an early hire in ELSI. What interested you in coming to Japan and to the just-beginning institute?

    I’ve been working with a lot of colleagues now at ELSI for many years. For example, Kei Hirose, the director, and I had been working on very similar topics and we had some nice results together. Hirose-san and others were trying to recruit me to come to Tokyo Tech in 2009 or 2010, but that was not a good time. So we waited until the opportunity came along, and I joined the WPI (World Premier International Research Center Initiative2) proposal as a principal investigator.

    I came to Tokyo Tech for the opening ceremony of ELSI in 2013 and heard impressive speeches from officials of MEXT (the Ministry of Education, Culture, Sports, Science and Technology) and from Mishima-sensei (Yoshinao Mishima, Tokyo Tech president from 2012 to 2018).

    They had a vision for how ELSI could help the university to become more sustainable and more international and more visible in the world. To work as a partner in that effort was something I strongly believed in and it drew me to Tokyo Tech. I still believe in that vision and that it’s a wonderful opportunity we have here.

    Why do you think the Japanese government has invested so much in the WPI program that includes ELSI?

    I think they’re doing this because the Japanese national universities are facing a demographic implosion, with fewer and fewer Japanese graduate students.

    The same thing happened in the U.S. and, if you go to top science and engineering institutions there, you’ll find the students are dominantly non-American. So this is the model for how a top university survives today — they internationalize.

    Tokyo Tech leadership has known about this for a long time. Hopefully they will use the lessons of ELSI — the success and the failures — to help the transformation into an international university. Our involvement in education is key to that, and I hope it continues to grow. Our exclusive use of English is also an important step forward for the university.

    WPI also wanted their institutes to be multi-disciplinary. We have embraced that and created a special environment for people from very, very different fields. They come together and talk with each other and have conversations that people say could only happen at ELSI. We often hear this from colleagues who come to visit. There might be a microbiologist talking with an astrophysicist, and the kind of thoughts they come up with together can be very unique.

    As a young person, what made you decide to go into your field of science?

    I was always interested in nature and when I was young we used to hike in the mountains. My father was studying at a school for mines in the U.S., though he was in chemistry and eventually became an expert in petroleum refining technology. But they had a geological museum there, and I grew really interested at a young age about the fossils and things like that. Also, I had a great high school teacher who inspired me to study geology when I went to college.

    I started off wanting to be a field geologist trotting around the world, but whenever I went someplace to do some geological mapping I wondered what was happening underneath me. Why are the rock layers tilted this way? Why is this fault here? Where did the magma come from? The answers to these questions always led to deeper in the Earth, to peeling back the layers to get at the causes. I then went into geophysics and seismology. I later started working in a high pressure laboratory doing experiments on rocks at high temperatures and pressures to simulate conditions deep inside the planet.

    Is your field a promising one for students, a field with future prospects?

    Absolutely. One of the new opportunities already present and growing more important is exoplanets. We’re starting to see thousands of planets beyond our solar system. So far most of the interpretative work of the observation of exoplanets has been made by astronomers and so models of the planets and ideas about the planets have been poorly developed. There’s going to be an increasing need for us to better characterize what these planets are like. Especially because we want to search for life, we have to focus on a specific promising planet and point the telescope there for some time.

    The way to make the decision of which planet to study is to have a better understanding of how planets work in general. Modeling the connection between the dynamics and evolution of planets and their physical properties — the high pressures and temperatures, whether they have plate tectonics, what is the volcanic activity, how was the atmosphere formed — all of these things are very central to tackling that science.

    Do you think scientists will ever have definite answers about how Earth went from having no life to having life?

    I don’t think we’ll be able to say with certainty how life started on Earth. But what we will be able to do is to understand how a range of different possibilities might have happened on Earth. I think that is very valuable. Because if we understand a range of ways that life could have originated on Earth, that will help us to then translate that to other planets. The more we learn about what was needed for life to begin here, the more we’ll have some general understanding of how that process should work elsewhere.

    But the particular path that Earth took will always be very difficult for us to piece together. Probably we’ll find that the evidence has been destroyed because the early Earth was so active, and what was on the surface and the crust is now deep inside.

    A kind of perfect crime.

    What would you say to students considering Tokyo Tech as a school to join?

    Tokyo Tech is one of the most ambitious universities. I see people here who are hungry and who want to work hard. I see more of this at Tokyo Tech than at most places, and I think that’s always the best kind of place for students to come. Students have a big role to play here in terms of the history that’s being made.

    Actually, I think it’s the most exciting place to study in Japan.

    What would you say to young people who are considering to become scientists?

    Being a scientist is a very special vocation. We are idealists in many ways who really care about the search for knowledge. That’s more important than anything else. More important than becoming rich. We really want to do the things that will fundamentally advance humankind’s ability to tackle the challenges that all of us face on the planet. We already know how important science is to creating a sustainable future for all of us; it will become even more important in the coming century, because the planet is not doing so well right now in terms of global warming and sustaining our food supplies. This will require taking a systems-level view and to grow this understanding of how planets live and can survive in the long term.

    I think science can bring a lot of new tools and intuitions to these problems in the future and as well to understanding what are the challenges we face and what things we should be concerned about. I hope that more young people become interested in science because the world needs you.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    tokyo-tech-campus

    Tokyo Tech is the top national university for science and technology in Japan with a history spanning more than 130 years. Of the approximately 10,000 students at the Ookayama, Suzukakedai, and Tamachi Campuses, half are in their bachelor’s degree program while the other half are in master’s and doctoral degree programs. International students number 1,200. There are 1,200 faculty and 600 administrative and technical staff members.

    In the 21st century, the role of science and technology universities has become increasingly important. Tokyo Tech continues to develop global leaders in the fields of science and technology, and contributes to the betterment of society through its research, focusing on solutions to global issues. The Institute’s long-term goal is to become the world’s leading science and technology university.

     
  • richardmitnick 11:36 am on May 4, 2019 Permalink | Reply
    Tags: "When it comes to planetary habitability it’s what’s inside that counts", A true picture of planetary habitability must consider how a planet’s atmosphere is linked to and shaped by what’s happening in its interior, , , , , , , Geophysics, , ,   

    From Carnegie Institution for Science: “When it comes to planetary habitability, it’s what’s inside that counts” 

    Carnegie Institution for Science
    From Carnegie Institution for Science

    May 01, 2019

    Which of Earth’s features were essential for the origin and sustenance of life? And how do scientists identify those features on other worlds?

    A team of Carnegie investigators with array of expertise ranging from geochemistry to planetary science to astronomy published this week in Science an essay urging the research community to recognize the vital importance of a planet’s interior dynamics in creating an environment that’s hospitable for life.

    With our existing capabilities, observing an exoplanet’s atmospheric composition will be the first way to search for signatures of life elsewhere. However, Carnegie’s Anat Shahar, Peter Driscoll, Alycia Weinberger, and George Cody argue that a true picture of planetary habitability must consider how a planet’s atmosphere is linked to and shaped by what’s happening in its interior.

    1
    Reprinted with permission from Shahar et. al., Science Volume 364:3(2019).

    For example, on Earth, plate tectonics are crucial for maintaining a surface climate where life can thrive. What’s more, without the cycling of material between its surface and interior, the convection that drives the Earth’s magnetic field would not be possible and without a magnetic field, we would be bombarded by cosmic radiation.

    “We need a better understanding of how a planet’s composition and interior influence its habitability, starting with Earth,” Shahar said. “This can be used to guide the search for exoplanets and star systems where life could thrive, signatures of which could be detected by telescopes.”

    It all starts with the formation process. Planets are born from the rotating ring of dust and gas that surrounds a young star. The elemental building blocks from which rocky planets form—silicon, magnesium, oxygen, carbon, iron, and hydrogen—are universal. But their abundances and the heating and cooling they experience in their youth will affect their interior chemistry and, in turn, things like ocean volume and atmospheric composition.

    “One of the big questions we need to ask is whether the geologic and dynamic features that make our home planet habitable can be produced on planets with different compositions,” Driscoll explained.

    The Carnegie colleagues assert that the search for extraterrestrial life must be guided by an interdisciplinary approach that combines astronomical observations, laboratory experiments of planetary interior conditions, and mathematical modeling and simulations.

    2
    Artist’s impression of the surface of the planet Barnard’s Star b courtesy of ESO/M. Kornmesser.

    “Carnegie scientists are long-established world leaders in the fields of geochemistry, geophysics, planetary science, astrobiology, and astronomy,” said Weinberger. “So, our institution is perfectly placed to tackle this cross-disciplinary challenge.”

    In the next decade as a new generation of telescopes come online, scientists will begin to search in earnest for biosignatures in the atmospheres of rocky exoplanets. But the colleagues say that these observations must be put in the context of a larger understanding of how a planet’s total makeup and interior geochemistry determines the evolution of a stable and temperate surface where life could perhaps arise and thrive.

    “The heart of habitability is in planetary interiors,” concluded Cody.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Carnegie Institution of Washington Bldg

    Carnegie Institution for Science

    Andrew Carnegie established a unique organization dedicated to scientific discovery “to encourage, in the broadest and most liberal manner, investigation, research, and discovery and the application of knowledge to the improvement of mankind…” The philosophy was and is to devote the institution’s resources to “exceptional” individuals so that they can explore the most intriguing scientific questions in an atmosphere of complete freedom. Carnegie and his trustees realized that flexibility and freedom were essential to the institution’s success and that tradition is the foundation of the institution today as it supports research in the Earth, space, and life sciences.

    6.5 meter Magellan Telescopes located at Carnegie’s Las Campanas Observatory, Chile.
    6.5 meter Magellan Telescopes located at Carnegie’s Las Campanas Observatory, Chile


    Carnegie Las Campanas 2.5 meter Irénée Dupont telescope, Atacama Desert, over 2,500 m (8,200 ft) high approximately 100 kilometres (62 mi) northeast of the city of La Serena,Chile


    Carnegie Institution Swope telescope at Las Campanas, Chile, 100 kilometres (62 mi) northeast of the city of La Serena. near the north end of a 7 km (4.3 mi) long mountain ridge. Cerro Las Campanas, near the southern end and over 2,500 m (8,200 ft) high, at Las Campanas, Chile

    [/caption]

     
  • richardmitnick 3:56 pm on March 5, 2019 Permalink | Reply
    Tags: , , Earthquake hazards, Geophysicists at Caltech have created a new method for determining earthquake hazards by measuring how fast energy is building up on faults in a specific region and then comparing that to how much is , Geophysics, , , The method also allows for an assessment of the likelihood of smaller earthquakes. If one excludes aftershocks the probability that a magnitude 6.0 or greater earthquake will occur in central LA over , They applied the new method to the faults underneath central Los Angeles and found that on the long-term average the strongest earthquake that is likely to occur along those faults is between magnitud, They find that the crust beneath Los Angeles does not seem to be being squeezed from south to north fast enough to make such an earthquake quite as likely, When one tectonic plate pushes against another elastic strain is built up along the boundary between the two plates. The strain increases until one plate either creeps slowly past the other or it jerk   

    From Caltech: “Fast, Simple New Assessment of Earthquake Hazard” 

    Caltech Logo

    From Caltech

    1
    Credit: Juan Vargas, Jean-Philippe Avouac, Chris Rollins / Caltech

    March 04, 2019

    Contact
    Robert Perkins
    (626) 395‑1862
    rperkins@caltech.edu

    Geophysicists at Caltech have created a new method for determining earthquake hazards by measuring how fast energy is building up on faults in a specific region, and then comparing that to how much is being released through fault creep and earthquakes.

    They applied the new method to the faults underneath central Los Angeles, and found that on the long-term average, the strongest earthquake that is likely to occur along those faults is between magnitude 6.8 and 7.1, and that a magnitude 6.8—about 50 percent stronger than the 1994 Northridge earthquake—could occur roughly every 300 years on average.

    That is not to say that a larger earthquake beneath central L.A. is impossible, the researchers say; rather, they find that the crust beneath Los Angeles does not seem to be being squeezed from south to north fast enough to make such an earthquake quite as likely.

    The method also allows for an assessment of the likelihood of smaller earthquakes. If one excludes aftershocks, the probability that a magnitude 6.0 or greater earthquake will occur in central LA over any given 10-year period is about 9 percent, while the chance of a magnitude 6.5 or greater earthquake is about 2 percent.

    A paper describing these findings was published by Geophysical Research Letters on February 27.

    These levels of seismic hazard are somewhat lower but do not differ significantly from what has already been predicted by the Working Group on California Earthquake Probabilities. But that is actually the point, the Caltech scientists say.

    Current state-of-the-art methods for assessing the seismic hazard of an area involve generating a detailed assessment of the kinds of earthquake ruptures that can be expected along each fault, a complicated process that relies on supercomputers to generate a final model. By contrast, the new method—developed by Caltech graduate student Chris Rollins and Jean-Philippe Avouac, Earle C. Anthony Professor of Geology and Mechanical and Civil Engineering—is much simpler, relying on the strain budget and the overall earthquake statistics in a region.

    “We basically ask, ‘Given that central L.A. is being squeezed from north to south at a few millimeters per year, what can we say about how often earthquakes of various magnitudes might occur in the area, and how large earthquakes might get?'” Rollins says.

    When one tectonic plate pushes against another, elastic strain is built up along the boundary between the two plates. The strain increases until one plate either creeps slowly past the other, or it jerks violently. The violent jerks are felt as earthquakes.

    Fortunately, the gradual bending of the crust between earthquakes can be measured at the surface by studying how the earth’s surface deforms. In a previous study [JGR Solid Earth] (done in collaboration with Caltech research software engineer Walter Landry; Don Argus of the Jet Propulsion Laboratory, which is managed by Caltech for NASA; and Sylvain Barbot of USC), Avouac and Rollins measured ground displacement using permanent global positioning system (GPS) stations that are part of the Plate Boundary Observatory network, supported by the National Science Foundation (NSF) and NASA. The GPS measurements revealed how fast the land beneath L.A. is being bent. From that, the researchers calculated how much strain was being released by creep and how much was being stored as elastic strain available to drive earthquakes.

    This research was supported by a NASA Earth and Space Science Fellowship.

    See the full article here .

    Earthquake Alert

    1

    Earthquake Alert

    Earthquake Network projectEarthquake Network is a research project which aims at developing and maintaining a crowdsourced smartphone-based earthquake warning system at a global level. Smartphones made available by the population are used to detect the earthquake waves using the on-board accelerometers. When an earthquake is detected, an earthquake warning is issued in order to alert the population not yet reached by the damaging waves of the earthquake.

    The project started on January 1, 2013 with the release of the homonymous Android application Earthquake Network. The author of the research project and developer of the smartphone application is Francesco Finazzi of the University of Bergamo, Italy.

    Get the app in the Google Play store.

    3
    Smartphone network spatial distribution (green and red dots) on December 4, 2015

    Meet The Quake-Catcher Network

    QCN bloc

    Quake-Catcher Network

    The Quake-Catcher Network is a collaborative initiative for developing the world’s largest, low-cost strong-motion seismic network by utilizing sensors in and attached to internet-connected computers. With your help, the Quake-Catcher Network can provide better understanding of earthquakes, give early warning to schools, emergency response systems, and others. The Quake-Catcher Network also provides educational software designed to help teach about earthquakes and earthquake hazards.

    After almost eight years at Stanford, and a year at CalTech, the QCN project is moving to the University of Southern California Dept. of Earth Sciences. QCN will be sponsored by the Incorporated Research Institutions for Seismology (IRIS) and the Southern California Earthquake Center (SCEC).

    The Quake-Catcher Network is a distributed computing network that links volunteer hosted computers into a real-time motion sensing network. QCN is one of many scientific computing projects that runs on the world-renowned distributed computing platform Berkeley Open Infrastructure for Network Computing (BOINC).

    The volunteer computers monitor vibrational sensors called MEMS accelerometers, and digitally transmit “triggers” to QCN’s servers whenever strong new motions are observed. QCN’s servers sift through these signals, and determine which ones represent earthquakes, and which ones represent cultural noise (like doors slamming, or trucks driving by).

    There are two categories of sensors used by QCN: 1) internal mobile device sensors, and 2) external USB sensors.

    Mobile Devices: MEMS sensors are often included in laptops, games, cell phones, and other electronic devices for hardware protection, navigation, and game control. When these devices are still and connected to QCN, QCN software monitors the internal accelerometer for strong new shaking. Unfortunately, these devices are rarely secured to the floor, so they may bounce around when a large earthquake occurs. While this is less than ideal for characterizing the regional ground shaking, many such sensors can still provide useful information about earthquake locations and magnitudes.

    USB Sensors: MEMS sensors can be mounted to the floor and connected to a desktop computer via a USB cable. These sensors have several advantages over mobile device sensors. 1) By mounting them to the floor, they measure more reliable shaking than mobile devices. 2) These sensors typically have lower noise and better resolution of 3D motion. 3) Desktops are often left on and do not move. 4) The USB sensor is physically removed from the game, phone, or laptop, so human interaction with the device doesn’t reduce the sensors’ performance. 5) USB sensors can be aligned to North, so we know what direction the horizontal “X” and “Y” axes correspond to.

    If you are a science teacher at a K-12 school, please apply for a free USB sensor and accompanying QCN software. QCN has been able to purchase sensors to donate to schools in need. If you are interested in donating to the program or requesting a sensor, click here.

    BOINC is a leader in the field(s) of Distributed Computing, Grid Computing and Citizen Cyberscience.BOINC is more properly the Berkeley Open Infrastructure for Network Computing, developed at UC Berkeley.

    Earthquake safety is a responsibility shared by billions worldwide. The Quake-Catcher Network (QCN) provides software so that individuals can join together to improve earthquake monitoring, earthquake awareness, and the science of earthquakes. The Quake-Catcher Network (QCN) links existing networked laptops and desktops in hopes to form the worlds largest strong-motion seismic network.

    Below, the QCN Quake Catcher Network map
    QCN Quake Catcher Network map

    ShakeAlert: An Earthquake Early Warning System for the West Coast of the United States

    The U. S. Geological Survey (USGS) along with a coalition of State and university partners is developing and testing an earthquake early warning (EEW) system called ShakeAlert for the west coast of the United States. Long term funding must be secured before the system can begin sending general public notifications, however, some limited pilot projects are active and more are being developed. The USGS has set the goal of beginning limited public notifications in 2018.

    Watch a video describing how ShakeAlert works in English or Spanish.

    The primary project partners include:

    United States Geological Survey
    California Governor’s Office of Emergency Services (CalOES)
    California Geological Survey
    California Institute of Technology
    University of California Berkeley
    University of Washington
    University of Oregon
    Gordon and Betty Moore Foundation

    The Earthquake Threat

    Earthquakes pose a national challenge because more than 143 million Americans live in areas of significant seismic risk across 39 states. Most of our Nation’s earthquake risk is concentrated on the West Coast of the United States. The Federal Emergency Management Agency (FEMA) has estimated the average annualized loss from earthquakes, nationwide, to be $5.3 billion, with 77 percent of that figure ($4.1 billion) coming from California, Washington, and Oregon, and 66 percent ($3.5 billion) from California alone. In the next 30 years, California has a 99.7 percent chance of a magnitude 6.7 or larger earthquake and the Pacific Northwest has a 10 percent chance of a magnitude 8 to 9 megathrust earthquake on the Cascadia subduction zone.

    Part of the Solution

    Today, the technology exists to detect earthquakes, so quickly, that an alert can reach some areas before strong shaking arrives. The purpose of the ShakeAlert system is to identify and characterize an earthquake a few seconds after it begins, calculate the likely intensity of ground shaking that will result, and deliver warnings to people and infrastructure in harm’s way. This can be done by detecting the first energy to radiate from an earthquake, the P-wave energy, which rarely causes damage. Using P-wave information, we first estimate the location and the magnitude of the earthquake. Then, the anticipated ground shaking across the region to be affected is estimated and a warning is provided to local populations. The method can provide warning before the S-wave arrives, bringing the strong shaking that usually causes most of the damage.

    Studies of earthquake early warning methods in California have shown that the warning time would range from a few seconds to a few tens of seconds. ShakeAlert can give enough time to slow trains and taxiing planes, to prevent cars from entering bridges and tunnels, to move away from dangerous machines or chemicals in work environments and to take cover under a desk, or to automatically shut down and isolate industrial systems. Taking such actions before shaking starts can reduce damage and casualties during an earthquake. It can also prevent cascading failures in the aftermath of an event. For example, isolating utilities before shaking starts can reduce the number of fire initiations.

    System Goal

    The USGS will issue public warnings of potentially damaging earthquakes and provide warning parameter data to government agencies and private users on a region-by-region basis, as soon as the ShakeAlert system, its products, and its parametric data meet minimum quality and reliability standards in those geographic regions. The USGS has set the goal of beginning limited public notifications in 2018. Product availability will expand geographically via ANSS regional seismic networks, such that ShakeAlert products and warnings become available for all regions with dense seismic instrumentation.

    Current Status

    The West Coast ShakeAlert system is being developed by expanding and upgrading the infrastructure of regional seismic networks that are part of the Advanced National Seismic System (ANSS); the California Integrated Seismic Network (CISN) is made up of the Southern California Seismic Network, SCSN) and the Northern California Seismic System, NCSS and the Pacific Northwest Seismic Network (PNSN). This enables the USGS and ANSS to leverage their substantial investment in sensor networks, data telemetry systems, data processing centers, and software for earthquake monitoring activities residing in these network centers. The ShakeAlert system has been sending live alerts to “beta” users in California since January of 2012 and in the Pacific Northwest since February of 2015.

    In February of 2016 the USGS, along with its partners, rolled-out the next-generation ShakeAlert early warning test system in California joined by Oregon and Washington in April 2017. This West Coast-wide “production prototype” has been designed for redundant, reliable operations. The system includes geographically distributed servers, and allows for automatic fail-over if connection is lost.

    This next-generation system will not yet support public warnings but does allow selected early adopters to develop and deploy pilot implementations that take protective actions triggered by the ShakeAlert notifications in areas with sufficient sensor coverage.

    Authorities

    The USGS will develop and operate the ShakeAlert system, and issue public notifications under collaborative authorities with FEMA, as part of the National Earthquake Hazard Reduction Program, as enacted by the Earthquake Hazards Reduction Act of 1977, 42 U.S.C. §§ 7704 SEC. 2.

    For More Information

    Robert de Groot, ShakeAlert National Coordinator for Communication, Education, and Outreach
    rdegroot@usgs.gov
    626-583-7225

    Learn more about EEW Research

    ShakeAlert Fact Sheet

    ShakeAlert Implementation Plan


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    Please help promote STEM in your local schools.


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    The California Institute of Technology (commonly referred to as Caltech) is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. “The mission of the California Institute of Technology is to expand human knowledge and benefit society through research integrated with education. We investigate the most challenging, fundamental problems in science and technology in a singularly collegial, interdisciplinary atmosphere, while educating outstanding students to become creative members of society.”

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  • richardmitnick 1:22 pm on March 9, 2018 Permalink | Reply
    Tags: , Diamonds with ice VII, , , Geophysics, ice VII, Pockets of water may lay deep below Earth’s surface,   

    From Science: “Pockets of water may lay deep below Earth’s surface” 

    AAAS
    Science Magazine

    Mar. 8, 2018
    Sid Perkins

    1
    New evidence of water pockets has been found hundreds of kilometers deep inside our planet. Claus Lunau/Science Source.

    Small pockets of water exist deep beneath Earth’s surface, according to an analysis of diamonds belched from hundreds of kilometers within our planet. The work, which also identifies a weird form of crystallized water known as ice VII, suggests that material may circulate more freely at some depths within Earth than previously thought. Geophysical models of that flow, which ultimately influences the frequency of earthquakes driven by the scraping of tectonic plates at Earth’s surface, may need to be substantially tweaked, scientists say. Such models also help scientists estimate the long-term rates of heat flow through Earth’s surface and into space.

    “These diamonds seem to be returning confirmation, and a few new surprises, of what’s happening deep within Earth,” says Steven Shirey, a geochemist at the Carnegie Institution for Science in Washington, D.C., who was not involved in the study. One of the biggest surprises, he suggests, is evidence for the presence of unbound water at depths below 600 kilometers.

    Pure diamonds are made of nothing but carbon, but most contain small impurities that take the form of tiny crystals. These inclusions offer clues about how and where the gems formed, says Oliver Tschauner, a mineralogist at University of Nevada in Las Vegas. In a 2016 study, for example, metal-rich inclusions found in dozens of large, clear diamonds suggested that those gemstones formed in pockets of liquid metal.

    Recently, Tschauner and his colleagues analyzed diamonds unearthed at several sites in southern Africa and China. More than a dozen of them contained a new type of inclusion—a distinct form of crystallized water known as ice VII. (Scientists have discovered more than a dozen types of ice crystals, including ice IX—which, unlike Kurt Vonnegut’s fictional ice-nine, doesn’t freeze up the world’s oceans.) Ice VII is well known from lab studies of materials under high pressure, Tschauner says, but the samples he and his colleagues describe are the first known natural samples, the researchers report today in Science. Based on the team’s data, ice VII has been declared a new mineral.

    2
    X-rays scattered from water trapped in a diamond (light gray pixels seen near arrow) suggest that watery fluids can be found deep inside Earth.
    Tschauner Et al./Science (2018)

    The identification of ice inside those diamonds provides scientists with more than a nifty new mineral, Tschauner says. It also suggests that pockets of watery fluids exist at great depths in Earth’s mantle [Science]. This water, rather than being chemically bound in rocks in combinations called hydrated minerals, is free-floating and remains a liquid—despite the high temperatures found in the mantle, the layer sandwiched between Earth’s crust and core. The team’s analyses suggest that some of the diamonds they studied formed at depths between 610 and 800 kilometers below Earth’s surface—the first direct evidence of unbonded water at such extreme depths, Tschauner notes. Nevertheless, the new research doesn’t help pin down how large those pockets are or how common they may be.

    Alongside the ice VII inclusions were tiny crystals of calcite and various types of salts, Tschauner says. Thus, he and his colleagues contend that the diamonds they analyzed crystallized in pockets of watery, salty fluid at depths well below the level at which scientists had previously identified water unbound to other minerals.

    The presence of watery fluids at or below the boundary between the upper and lower mantle could definitely affect how and where heat is generated in the mantle, says Oded Navon, a mantle geochemist at The Hebrew University of Jerusalem. For instance, such watery fluids could more readily carry certain forms of easily dissolved radioactive elements from one part of the mantle to another. That could affect where in the mantle heat-generating radioactive decay occurs, which, in turn, could make the heated areas less viscous and thus prone to flow more readily. All these changes could influence the rates, over the long term, at which heat escapes from Earth’s interior.

    Among other things, the varying composition of materials at different layers of the mantle can affect where and how well tectonic slabs that have sunk back into Earth’s interior melt and release their minerals, Tschauner and his team contend. For instance, the density and viscosity of Earth’s interior affect the level at which sinking slabs reach neutral buoyancy, thus stalling their descent. That, in turn, influences where the slabs melt and release the water and other minerals they hold. Overall, the team’s new findings may lead to more accurate models of what’s going on at different depths deep within Earth.

    See the full article here .

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  • richardmitnick 1:03 pm on August 18, 2017 Permalink | Reply
    Tags: , Geophysics, Hot spot at Hawaii? Not so fast, Hot spots around the globe can be used to determine how fast tectonic plates move, , , , Seamounts, The Pacific Plate moves relative to the hot spots at about 100 millimeters per year   

    From Rice: “Hot spot at Hawaii? Not so fast” 

    Rice U bloc

    Rice University

    August 18, 2017
    Mike Williams

    Rice University scientists’ model shows global mantle plumes don’t move as quickly as thought

    Through analysis of volcanic tracks, Rice University geophysicists have concluded that hot spots like those that formed the Hawaiian Islands aren’t moving as fast as recently thought.

    Hot spots are areas where magma pushes up from deep Earth to form volcanoes. New results from geophysicist Richard Gordon and his team confirm that groups of hot spots around the globe can be used to determine how fast tectonic plates move.

    1
    Rice University geophysicists have developed a method that uses the average motion of hot-spot groups by plate to determine that the spots aren’t moving as fast as geologists thought. For example, the Juan Fernandez Chain (outlined by the white rectangle) on the Nazca Plate west of Chile was formed by a hot spot now at the western end of the chain as the Nazca moved east-northeast relative to the hotspot forming the chain that includes Alejandro Selkirk and Robinson Crusoe islands. The white arrow shows the direction of motion of the Nazca Plate relative to the hot spot, and it is nearly indistinguishable from the direction predicted from global plate motions relative to all the hot spots on the planet (green arrow). The similarity in direction indicates that very little motion of the Juan Fernandez hot spot relative to other hot spots is needed to explain its trend. Illustration by Chengzu Wang.

    Gordon, lead author Chengzu Wang and co-author Tuo Zhang developed a method to analyze the relative motion of 56 hot spots grouped by tectonic plates. They concluded that the hot-spot groups move slowly enough to be used as a global reference frame for how plates move relative to the deep mantle. This confirmed the method is useful for viewing not only current plate motion but also plate motion in the geologic past.

    The study appears in Geophysical Research Letters.

    Hot spots offer a window into the depths of Earth, as they mark the tops of mantle plumes that carry hot, buoyant rock from deep Earth to near the surface and produce volcanoes. These mantle plumes were once thought to be straight and stationary, but recent results suggested they can also shift laterally in the convective mantle over geological time.

    The primary evidence of plate movement relative to the deep mantle comes from volcanic activity that forms mountains on land, islands in the ocean or seamounts, mountain-like features on the ocean floor. A volcano forms on a tectonic plate above a mantle plume. As the plate moves, the plume gives birth to a series of volcanoes. One such series is the Hawaiian Islands and the Emperor Seamount Chain; the youngest volcanoes become islands while the older ones submerge. The series stretches for thousands of miles and was formed as the Pacific Plate moved over a mantle plume for 80 million years.

    The Rice researchers compared the observed hot-spot tracks with their calculated global hot-spot trends and determined the motions of hot spots that would account for the differences they saw. Their method demonstrated that most hot-spot groups appear to be fixed and the remainder appear to move slower than expected.

    “Averaging the motions of hot-spot groups for individual plates avoids misfits in data due to noise,” Gordon said. “The results allowed us to say that these hot-spot groups, relative to other hot-spot groups, are moving at about 4 millimeters or less a year.

    “We used a method of analysis that’s new for hot-spot tracks,” he said. “Fortunately, we now have a data set of hot-spot tracks that is large enough for us to apply it.”

    For seven of the 10 plates they analyzed with the new method, average hot-spot motion measured was essentially zero, which countered findings from other studies that spots move as much as 33 millimeters a year. Top speed for the remaining hot-spot groups — those beneath the Eurasia, Nubia and North America plates — was between 4 and 6 millimeters a year but could be as small as 1 millimeter per year. That’s much slower than most plates move relative to the hot spots. For example, the Pacific Plate moves relative to the hot spots at about 100 millimeters per year.

    Gordon said those interested in paleogeography should be able to make use of the model. “If hot spots don’t move much, they can use them to study prehistorical geography. People who are interested in circum-Pacific tectonics, like how western North America was assembled, need to know that history of plate motion.

    “Others who will be interested are geodynamicists,” he said. “The motions of hot spots reflect the behavior of mantle. If the hot spots move slowly, it may indicate that the viscosity of mantle is higher than models that predict fast movement.”

    “Modelers, especially those who study mantle convection, need to have something on the surface of Earth to constrain their models, or to check if their models are correct,” Wang said. “Then they can use their models to predict something. Hot-spot motion is one of the things that can be used to test their models.”

    Gordon is the W.M. Keck Professor of Earth Science. Wang and Zhang are Rice graduate students. The National Science Foundation supported the research.

    See the full article here .

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    Rice U campus

    In his 1912 inaugural address, Rice University president Edgar Odell Lovett set forth an ambitious vision for a great research university in Houston, Texas; one dedicated to excellence across the range of human endeavor. With this bold beginning in mind, and with Rice’s centennial approaching, it is time to ask again what we aspire to in a dynamic and shrinking world in which education and the production of knowledge will play an even greater role. What shall our vision be for Rice as we prepare for its second century, and how ought we to advance over the next decade?

    This was the fundamental question posed in the Call to Conversation, a document released to the Rice community in summer 2005. The Call to Conversation asked us to reexamine many aspects of our enterprise, from our fundamental mission and aspirations to the manner in which we define and achieve excellence. It identified the pressures of a constantly changing and increasingly competitive landscape; it asked us to assess honestly Rice’s comparative strengths and weaknesses; and it called on us to define strategic priorities for the future, an effort that will be a focus of the next phase of this process.

     
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