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  • richardmitnick 4:15 pm on September 16, 2020 Permalink | Reply
    Tags: "Most landslides in western Oregon triggered by heavy rainfall not big earthquakes", , Geology, ,   

    From University of Washington: “Most landslides in western Oregon triggered by heavy rainfall, not big earthquakes” 

    From University of Washington

    September 16, 2020
    Hannah Hickey

    1
    The Oregon Coast Range seen at sunset. Credit: Sean LaHusen.

    Researchers at the University of Washington, Portland State University and the University of Oregon have shown that deep-seated landslides in the central Oregon Coast Range are triggered mostly by rainfall, not by large offshore earthquakes.

    The open-access paper was published Sept. 16 in Science Advances.

    “Geomorphologists have long understood the importance of rainfall in triggering landslides, and our study is simply driving home just how important it is,” said first author Sean LaHusen, who did the work as part of his doctorate at the UW. “Our results show that more frequent, localized landslide events triggered by rainfall are just as important to consider as less frequent but more far-reaching Cascadia Subduction Zone earthquakes.”

    2
    The Oregon Coast Range run from about Newport, Oregon, south to Port Orford. The low-lying mountain range is near the Cascadia Subduction Zone, an offshore fault that can trigger magnitude-9 earthquakes. Credit: LaHusen et al./Science Advances.

    Cascadia subduction zone.


    Cascadia plate zones.

    Heavy rains are known to cause landslides that can be disruptive and deadly. A less frequent trigger for a landslide would be a rupture of the geologic fault off the coast of Washington and Oregon that’s known as the Cascadia Subduction Zone — adding to a long list of concerns after a major earthquake. Landslide risks of all types increase if human development or wildfires remove trees, taking away the roots that stabilize the soil.

    Recent research in Nepal and Japan, however, suggests that offshore earthquakes might not trigger as many landslides as previously believed. The new study finds a similar situation in the Pacific Northwest.

    “We aren’t suggesting that the landscape had no response to these magnitude-9 earthquakes, but that the deeper-seated landslide deposits and scars out on the Oregon Coast Range hillslopes today were primarily triggered by precipitation events,” said senior author Alison Duvall, a UW associate professor of Earth and space sciences. “We conclude that past Cascadia Subduction Zone earthquakes triggered no more than a few hundred deep landslides during great earthquake events.”

    The researchers used high-resolution aerial laser maps of the Oregon coast to look at 1,000 years of landslide activity. Landslides tended to happen in places with heavier rainfall, they found. But surprisingly, there was no detectable change in the number of deep landslides at the time of the large earthquake that shook the Pacific Northwest in 1700, or for two earlier offshore earthquakes that happened in roughly the years 1150 and 1470.

    3
    This Google Earth image shows a site about 5 miles south of Florence, on the central Oregon coast, that experienced a landslide in winter 2017. The new paper uses aerial imagery that penetrates through tree cover to study the occurrence of such slides over more than 1,000 years. Credit: Google Earth/Sean LaHusen.

    Duvall, LaHusen and co-author Adam Booth at Portland State University developed a method for dating landslides while studying the site of the deadly March 2014 mudslide in Oso, Washington. In that study [Geology], they used high-resolution images to view the surface roughness. Over time, soil settles and exposed rock erodes. The surface gets smoother, so surface roughness can be used to calculate a landslide’s age.

    “The central Oregon Coast Range offered a massive, 10,000-square-kilometer natural laboratory to explore patterns in deep-seated landslide events through space and time,” LaHusen said. “It’s 50-million-year-old sandstone and siltstone that was deposited offshore, buried and compacted, and then uplifted to form the mountains we see today.”

    Aerial lidar maps with less than 3-foot resolution revealed 9,938 landslides inside the study area. Researchers narrowed those down to 2,676 landslides that have happened within the past 1,000 years, and then looked at the landslide frequency during that time.

    4
    Within the study zone, seen on the left, analyses of aerial lidar imagery revealed almost 10,000 landslides. On the subset at the right, landslides that have occurred in the past thousand years are shown in red. Credit: LaHusen et al./Science Advances.

    For the new study, they applied their method to a larger area in the central Oregon Coast Range. To study landslide activity related to the Cascadia Subduction Zone, the researchers needed an area near the Cascadia fault zone with a consistent rock type and publicly available lidar imagery.

    Researchers caution that the study doesn’t apply to shallow landslides, which frequently occur during earthquakes but leave no long-term evidence and can’t be analyzed with this method, or to different soil types, and so doesn’t necessarily apply to other regions. The research also didn’t consider shallower earthquakes from surface faults.

    But the paper does support recent findings in Asia suggesting that offshore earthquakes don’t trigger as many deep landslides as once believed, and that rainfall may be the bigger factor in shaping the landscape over longer timescales.

    “These data strengthen the point that we don’t need big earthquakes to trigger large and devastating landslides in Washington and Oregon,” Duvall said. “Seasonal precipitation and large rain events are important to focus on in landslide preparedness planning.”

    This research was funded by the National Science Foundation and the Geological Society of America. The team began the work as part of the UW M9 Project, which is studying magnitude-9 earthquakes from the fault that runs parallel to the Washington and Oregon coastlines. Slips along this fault can lead to a so-called “Big One,” which last struck the Pacific Northwest in 1700.

    Other co-authors are Alex Grant, Benjamin Mishkin, David Montgomery and Joseph Wartman at the UW; and Will Struble and Josh Roering at the University of Oregon. LaHusen is now working at the U.S. Geological Survey in Mountain View, California.

    5
    Co-authors Will Struble (left) and Alison Duvall dig into a landslide deposit near the community of Sitkum, Oregon, in search of wood that could be used for radiocarbon dating of the past slide. Credit: Sean LaHusen.

    See the full article here .


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    u-washington-campus
    The University of Washington is one of the world’s preeminent public universities. Our impact on individuals, on our region, and on the world is profound — whether we are launching young people into a boundless future or confronting the grand challenges of our time through undaunted research and scholarship. Ranked number 10 in the world in Shanghai Jiao Tong University rankings and educating more than 54,000 students annually, our students and faculty work together to turn ideas into impact and in the process transform lives and our world. For more about our impact on the world, every day.
    So what defines us —the students, faculty and community members at the University of Washington? Above all, it’s our belief in possibility and our unshakable optimism. It’s a connection to others, both near and far. It’s a hunger that pushes us to tackle challenges and pursue progress. It’s the conviction that together we can create a world of good. Join us on the journey.

     
  • richardmitnick 10:35 am on September 15, 2020 Permalink | Reply
    Tags: "Meteorite strikes may create unexpected form of silica", , , , , , Geology   

    From Carnegie Institution for Science: “Meteorite strikes may create unexpected form of silica” 

    Carnegie Institution for Science
    From Carnegie Institution for Science

    August 26, 2020

    1
    A photograph of a meteorite strike site in Coconino County, Arizona. New work from Carnegie’s Sally June Tracy and collaborators Stefan Turneaure of Washington State University and Thomas Duffy of Princeton University reveals an unexpected new form of silica created in the type of extreme conditions caused by an impact. Image is courtesy of Shutterstock.

    2
    X-ray diffraction images showing the new form of silica created by sending an intense shock wave through a sample of quartz using a specialized gas gun. When the x-rays bounce off repeating planes of a crystalline structure, they scatter. This creates a distinctive ring pattern. Each ring is associated with a different plane and together this data can tell researchers about the material’s atomic-level architecture. Image is courtesy of Sally June Tracy, Stefan Turneaure, and Thomas Duffy.

    When a meteorite hurtles through the atmosphere and crashes to Earth, how does its violent impact alter the minerals found at the landing site? What can the short-lived chemical phases created by these extreme impacts teach scientists about the minerals existing at the high-temperature and pressure conditions found deep inside the planet?

    New work led by Carnegie’s Sally June Tracy examined the crystal structure of the silica mineral quartz under shock compression and is challenging longstanding assumptions about how this ubiquitous material behaves under such intense conditions. The results are published in Science Advances.

    “Quartz is one of the most abundant minerals in Earth’s crust, found in a multitude of different rock types,” Tracy explained. “In the lab, we can mimic a meteorite impact and see what happens.”

    Tracy and her colleagues—Washington State University’s (WSU) Stefan Turneaure and Princeton University’s Thomas Duffy, a former Carnegie Fellow—used specialized impact facilities to accelerate projectiles into quartz samples at extremely high speeds—several times faster than a bullet fired from a rifle. Special x-ray instruments were used to discern the crystal structure of the material that forms less than one-millionth of a second after impact. Experiments were carried out at the Dynamic Compression Sector (DCS), which is operated by WSU and located at the Advanced Photon Source, Argonne National Laboratory.

    Quartz is made up of one silicon atom and two oxygen atoms arranged in a tetrahedral lattice structure. Because these elements are also common in the silicate-rich mantle of the Earth, discovering the changes quartz undergoes at high-pressure and -temperature conditions, like those found in the Earth’s interior, could also reveal details about the planet’s geologic history.

    When a material is subjected to extreme pressures and temperatures, its internal atomic structure can be re-shaped, causing its properties to shift. For example, both graphite and diamond are made from carbon. But graphite, which forms at low pressure, is soft and opaque, and diamond, which forms at high pressure, is super-hard and transparent. The different arrangements of carbon atoms determine their structures and their properties, and that in turn affects how we engage with and use them.

    Despite decades of research, there has been a long-standing debate in the scientific community about what form silica would take during an impact event, or under dynamic compression conditions such as those deployed by Tracy and her collaborators. Under shock loading, silica is often assumed to transform to a dense crystalline form known as stishovite—a structure believed to exist in the deep Earth. Others have argued that because of the fast timescale of the shock the material will instead adopt a dense, glassy structure.

    Tracy and her team were able to demonstrate that counter to expectations, when subjected to a dynamic shock of greater than 300,000 times normal atmospheric pressure, quartz undergoes a transition to a novel disordered crystalline phase, whose structure is intermediate between fully crystalline stishovite and a fully disordered glass. However, the new structure cannot last once the burst of intense pressure has subsided.

    “Dynamic compression experiments allowed us to put this longstanding debate to bed,” Tracy concluded. “What’s more, impact events are an important part of understanding planetary formation and evolution and continued investigations can reveal new information about these processes.”

    This work is based on experiments performed at the Dynamic Compression Sector, operated by WSU under a DOE/ NNSA award. This research used the resources of the Advanced Photon Source, a Department of Energy Office of Science User Facility operated for the DOE Office of Science by the Argonne National Laboratory.


    ANL Advanced Photon Source.

    See the full article here .


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    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.

    Carnegie 6.5 meter Magellan Baade and Clay Telescopes located at Carnegie’s Las Campanas Observatory, Chile. over 2,500 m (8,200 ft) high.


    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 1-meter 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.

     
  • richardmitnick 3:42 pm on September 11, 2020 Permalink | Reply
    Tags: "Cratons Mark the Spot for Mineral Bonanzas", , Cratons are deep extratough regions of the lithosphere., Cratons- where thinning lithosphere made sedimentary basins perfect for metal precipitation., , , Geology, Lithospheric thickness can serve as a treasure map., Sedimentary deposits generally provide the biggest jackpot for mining companies with some finds containing more than 10 megatonnes of metal.   

    From Eos: “Cratons Mark the Spot for Mineral Bonanzas” 

    From AGU
    Eos news bloc

    From Eos

    A new map of the thickness of Earth’s lithosphere contains clues to large deposits of key metals.

    9.11.20
    Bas den Hond

    1
    Productive lead (Pb), zinc (Zn), and copper (Cu) mines line up with the edges of cratons, where thinning lithosphere made sedimentary basins perfect for metal precipitation. Ga = billion years ago; km = kilometers; Mt = megatonnes; CD = clastic dominated; MVT = Mississippi Valley type; sed = sedimentary. Credit: Mark Hoggard.

    The search for deposits of lead, zinc, copper, and nickel might soon become much less of a hit-and-miss activity. Instead of trying their luck over wide areas, mining companies should focus their efforts—and billions of dollars in exploration expenses—on the contours of thick, old pieces of lithosphere strewn across Earth’s continents: cratons.

    Lithospheric thickness can serve as a treasure map, according to Mark Hoggard, an Earth scientist at Harvard University and Columbia University, and his colleagues from the United Kingdom and Australia. They reported their findings in Nature Geoscience.

    Hunting for Giants

    Metals are ingredients of many rocks, but to be exploitable, some process must concentrate them into localized deposits. For lead, zinc, copper, and nickel (collectively known as base metals), such deposits are either magmatic, associated with volcanism, or sedimentary, associated with material collected at the bottom of an inland body of water.

    Sedimentary deposits generally provide the biggest jackpot for mining companies, with some finds containing more than 10 megatonnes of metal. With magmatic deposits, only those of copper seem to be able to reach that size.

    Such giant deposits are sorely needed. “At the moment, due to massive advances in mobile technology and the need to decarbonize the global economy, we are needing more and more metals,” said study coauthor Fred Richards, an Earth and planetary scientist at Harvard University and Imperial College London. In-demand metals include “lead, zinc, copper, and nickel, but also lots of other metals that are accessories to these big deposits, such as cobalt, which goes into car batteries.”

    Considering that about three quarters of the world’s continents are covered by sedimentary basins, knowing to start looking there is of little help in detecting giant deposits. A first hint at how to limit the search space came from northern Australia, where Hoggard and his colleagues noticed that a number of large zinc deposits line up rather neatly along an arc. But it wasn’t clear what geological feature was connected to that shape.

    The group had been working on improved models of how seismic waves travel through Earth’s interior. The results of their work provided a new map of Australia’s lithospheric thickness—and suggested an explanation for that arc of zinc deposits. The line skirted the large craton that makes up the west of the continent.

    2
    Australia provided the first clues to how metal deposits might flock to the edges of cratons. IOCG = iron oxide copper gold ore deposits. Credit: Mark Hoggard.

    Intrigued, the researchers investigated the geography of deposits and cratons in all of Australia, and then worldwide, and found many such juxtapositions. A statistical analysis confirmed that what they saw was not due just to chance.

    Circulating and Scavenging

    But what makes large base metal deposits so likely to snuggle up to cratons? It turns out that such a location provides a whole slew of circumstances that facilitate the process of concentrating metals.

    That process generally starts with an inland sea becoming increasingly salty through evaporation. In the shallowest parts of the sea, the concentration will become so high that salts precipitate to the seafloor. When compressed by subsequent layers of sediment, these precipitates turn into salt rocks, such as gypsum, anhydrite, and halite.

    Seawater then percolates down through the salt rocks and very slowly, with speeds measured in meters per year, travels through faults into deeper rocks. If the heavy, briny fluid passes through oxidized rocks, it becomes oxidized itself, and as a result, it is easy for metals in the rocks to dissolve into the brine and be swept up with it. The resulting metal-rich fluid has been observed, for instance, below the Salton Sea in California.

    As the brine descends, it comes closer to the hot underside of the lithosphere and heats up and expands. This makes it less dense and thus more buoyant, to such an extent that it rises up again, until it cools—just enough to start to sink again. The brine may keep circulating in this way through sedimentary layers for long periods (there is some debate whether those periods are millions of years at a stretch or come in shorter bursts), scavenging metals as it flows.

    But sometimes brine passes through an environment that is reducing, meaning it counteracts the oxidized state of the fluid. In this case, metal finds it harder to stay dissolved in the brine, and some of it will precipitate out. Black shales, for instance, composed of mud sediments laid down in deeper portions of the inland sea, provide just such conditions, and build up metal deposits in their interstices.

    Digging Deeper

    Cratons are deep, extratough regions of the lithosphere. They don’t typically lend themselves to thinning or rifting. But that very resistance makes their edges likely places for thinning of the weaker surrounding lithosphere, and thus perfect for forming sedimentary basins.

    Such basins might even get stacked atop each other, as the lithosphere cycles through stretching and compressing phases. Weakened by the previous events, the edge will give way again and again, possibly allowing metal deposit formation.

    The lithosphere at a craton’s edge is still thicker than elsewhere on a continent, so stretching and thinning it take longer. The slowness of the process gives the brine more time to circulate, and the remaining thickness of the stretched craton’s edge gives it a longer way to go down before temperatures get too high for the metal precipitation processes to work. These circumstances increase the volume of the deposit.

    The research documenting deposits on the craton’s edge clearly has practical implications. According to Hoggard, “our maps work everywhere, including in continents where a geologist’s boot rarely hits the ground—for instance, in parts of Africa and Antarctica—and we can provide an actual probability that a deposit exists, which is what companies need to make financial decisions.”

    And according to the scientists, the research also provides evidence for the stability and longevity of cratons. For instance, some sedimentary metal deposits in North America have been dated to 0.5–1.5 billion years old. For at least that long—apparently while continents broke up, collided, and joined up again—the craton against whose edge these deposits were nestling stayed in one piece.

    It’s good research, according to Jon Hronsky of the mineral exploration consultancy Western Mining Services, which has offices in the United States and Australia. “However, it is a little bemusing to us in the mineral exploration geoscience community that this is the first time these sort of ideas are finally gaining some attention from the general geoscience community,” he told Eos in an email.

    According to Hronsky, “the idea that deep-seated cryptic patterns of weaknesses and discontinuities in the lithosphere control the location of major ore deposits is quite an old one,” and “concepts, relating lithospheric architecture to the location of major mineral deposits, have been fairly central to mineral exploration targeting, at least within the more progressive companies, for about two decades.”

    Hoggard agrees with that as far as magmatic deposits are concerned. But according to him, such relationships so far had not been established for sedimentary deposits. “The data sets we use to image lithospheric structure have only really become available within the last 10 years. Even if someone had an inkling of the relationship before now, they wouldn’t have been able to test it like we can today.”

    See the full article here .

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    Eos is the leading source for trustworthy news and perspectives about the Earth and space sciences and their impact. Its namesake is Eos, the Greek goddess of the dawn, who represents the light shed on understanding our planet and its environment in space by the Earth and space sciences.

     
  • richardmitnick 1:40 pm on September 11, 2020 Permalink | Reply
    Tags: , Bezymianny stratovolcano on the Kamchatka peninsula in eastern Russia., Geology, , ,   

    From Helmholtz Association of German Research Centres via phys.org: “Researchers document the ‘life cycle’ of a volcano” 

    From Helmholtz Association of German Research Centres

    via


    From phys.org

    1
    Bezymianny is an active stratovolcano on the Kamchatka peninsula in eastern Russia. Credit: GFZ.

    Volcanoes are born and die—and then grow again on their own remains. The decay of a volcano in particular is often accompanied by catastrophic consequences, as was the most recent case for Anak Krakatau in 2018.

    1
    Scientists say the Anak Krakatau volcanic island in Indonesia has lost three-quarters of its volume since it erupted in 2018, causing a deadly tsunami. And it is also considerably shorter.

    The flank of the volcano had collapsed, sliding into the sea. The resulting tsunami killed several hundred people on Indonesia’s coast.

    Continued volcanic activity after a collapse has not been documented in detail so far. Now, and for the first time, researchers from the German Research Center for Geosciences GFZ and Russian volcanologists present the results of a photogrammetric data series spanning seven decades for the Bezymianny volcano, Kamchatka, in the journal Nature Communications Earth and Environment. First author Alina Shevchenko from GFZ says, “Thanks to the German-Russian cooperation, we were able to analyze and reinterpret a unique data set.”

    Bezymianny had a collapse of its eastern sector in 1956. Photographs of helicopter overflights from Soviet times, in combination with more recent satellite drone data, have now been analyzed at GFZ Potsdam using state-of-the-art methods. The images show the rebirth of the volcano after its collapse. The initial re-growth began at separate vents about 400 meters apart. After about two decades, the activity increased and the vents slowly moved together. After about 50 years, the activity concentrated on a single vent, which allowed the growth of a new, steep cone.

    The authors of the study determined an average growth rate of 26,400 cubic meters per day—equivalent to about 1000 large dump trucks. The results make it possible to predict when the volcanic building may once again reach a critical height, after which it could collapse again under its own weight. The numerical modeling also explains the changes in stress within the volcanic rock and thus the migration of the eruption vents. Thomas Walter, volcanologist at the GFZ and co-author of the study, says, “Our results show that the decay and re-growth of a volcano has a major impact on the pathways of the magma in the depth. Thus, disintegrated and newly grown volcanoes show a kind of memory of their altered field of stress.” For future prognosis, this means that the history of birth and collapse must be included to produce estimates about possible eruptions or imminent collapses.

    See the full article here.

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    The Helmholtz Association

    The Helmholtz Association of German Research Centers was created in 1995 to formalise existing relationships between several globally-renowned independent research centres. The Helmholtz Association distributes core funding from the German Federal Ministry of Education and Research (BMBF) to its, now, 19 autonomous research centers and evaluates their effectiveness against the highest international standards.

     
  • richardmitnick 9:43 am on September 11, 2020 Permalink | Reply
    Tags: "Gobekli Tepe: The world’s first astronomical observatory?", , , , , Geology,   

    From Astronomy Magazine: “Gobekli Tepe: The world’s first astronomical observatory?” 

    From Astronomy Magazine

    September 4, 2020
    Eric Betz

    Pseudoscience and genuine archaeological mysteries surround humanity’s oldest known temple. But was it the world’s first astronomical observatory?

    1
    The remains of Gobekli Tepe in Turkey. It is one of the oldest settlements in the world. Credit: 0meer/Shuttestock.

    Earth’s Northern Hemisphere was covered in enormous Ice Age glaciers when a group of hunter-gatherers in southern Turkey began constructing the world’s first known temple. The site, called Gobekli Tepe, was built roughly 12,000 years ago, with some parts appearing to be even older. However, because the ancient temple is so vast and complex, archaeologists have been busy excavating it since its discovery in 1994.

    Along the way, they’ve uncovered strange animal carvings, towering stone pillars, and the earliest known evidence of megalithic rituals. But despite all those years of research, they’re still working to unravel the site’s biggest mysteries: Who built it, and why?

    World’s first observatory?

    Gobekli Tepe’s design and age have captured the public’s imagination for decades. It’s been the subject of widespread, and often breathless, press coverage and documentaries, as well as countless conspiracy theories, from aliens to fantastical claims about ancient, technologically advanced civilizations. Some scientists, primarily those not connected to the core group excavating the site, have speculated that Gobekli Tepe was actually an astronomical observatory, or perhaps even the biblical Garden of Eden.

    There are two major claims that those who think Gobekli Tepe had celestial connections point to. One suggests that the site was aligned with the night sky, particularly the star Sirius, because the local people worshiped the star like other cultures in the region did thousands of years later. Another claims that carvings at Gobekli Tepe record a comet impact that hit Earth at the end of the Ice Age.

    If either of those things are true, Gobekli Tepe’s extreme age would indeed make it the world’s oldest known astronomical site.

    However, those claims of Gobekli Tepe’s connection to the night sky have been largely rejected by the main team actual excavating the temple. According to them, while the archaeological site is remarkably well preserved, the forces of time have changed the location of certain features.

    For example, studies suggest some of the pillars were removed and recycled elsewhere. Furthermore, later civilizations in the area — and, more recently, farmers — have rearranged portions of certain pillars, even breaking pieces off.

    The researchers have since tried their best to restore Gobekli Tepe’s pillars to their original locations, but the initial layout of the site’s stunning round buildings remains up for debate. That makes it impossible, at the moment, for archaeologists to know whether Gobekli Tepe had any astronomical significance at all.

    But there’s another, more obvious, potential reason to doubt the site’s buildings were once aligned to the stars. “There is the significant possibility that we are dealing with roofed structures; this fact alone would pose limitations to a function as sky observatories,” the research team wrote in a journal article [http://maajournal.com/Issues/2017/Vol17-2/Matters%20arising%2017%282%29.pdf] addressing the astronomical claims.

    2
    An aerial view of Gobekli Tepe reveals its sweeping expanse. The entire hillside shown here was made by human hands more than 10,000 years ago.
    Credit: Erhan Kücuk/German Archaeological Institute.

    Sharing creates a society

    For the team surveying Gobekli Tepe, the truth of the site, as they see it, is just as surprising — even without the astronomical connection.

    Archaeologists suspected that humans only began building complex societies and structures after the invention of agriculture. They also thought that complex religions only emerged after those events.

    Gobekli Tepe overthrows those theories. The site sits in the core of the Fertile Crescent, a region of the Middle East historically considered the birthplace of farming, writing and more. Yet, Gobekli Tepe was a pre-agricultural society; it was built before people in the region started farming.

    At a casual glance, Gobekli Tepe looks like an ordinary hill. So, researchers originally didn’t think much of it when a few meager stone structures were discovered on the hilltop in the 1960s. But, in 1994, when Klaus Schmidt of the German Archaeological Institute was finishing some excavation work at a nearby Stone Age settlement, he decided to reexamine the Gobekli Tepe hilltop. To his surprise, he recognized the few remnants he found on the surface had similar elements, suggesting there might be more buried below.

    Over the years that followed, the staggering scale of his discovery became clear. The entire hill was constructed by humans. All that dirt hides dozens of structures spread across an area some 1,000 feet wide and 50 feet tall. The people who built the site constructed large, intricately-decorated stone circles, later burying them in sand.

    The discovery sent shockwaves through the archaeological community because Gobekli Tepe couldn’t have been built by farmers. Farming didn’t really exist at that point. Plus, with no domesticated pack animals or metal tools to lighten the load, Gobekli Tepe would’ve had to have been built using rudimentary instruments and human hands.

    At 12,000 years old, Gobekli Tepe predated humanity’s oldest known civilizations. Its megalithic temples were cut from rock millennia before the 4,500-year-old pyramids in Egypt, 5,000-year-old Stonehenge in England, or 7,000-year-old Nabta Playa, the oldest known astronomical site.

    3
    The stone circle of Nabta Playa marks the summer solstice, a time that coincided with the arrival of monsoon rains in the Sahara Desert thousands of years ago. Credit: Wikimedia Commons.

    It even seems construction on some parts of Gobekli Tepe might have began as far back as 14,000 or 15,000 years ago.

    Still, there isn’t any evidence suggesting people actually lived at Gobekli Tepe. There were no burials and no apparent homes. So, to better understand who the site’s visitors were, scientists were forced to look to the nearby countryside.

    When they did, they found signs that for centuries before Gobekli Tepe appeared, Stone Age hunter-gatherers in the region seemed to be building small, permanent settlements where they lived communally, sharing their foraged resources. If that’s confirmed, then such sharing might have helped spawn the creation of society.

    But even then, why did hunter-gatherers from these surrounding communities seemingly work together in large numbers to build Gobekli Tepe? The answer to that question remains one of its biggest lingering mysteries.

    4
    The T-shaped Pillar 43 at Gobekli Tepe has drawn endless speculation about its meaning. The archaeologists who discovered it say it’s likely impossible to unravel what it meant to those who built it, and that it’s also far from the only ornately-carved pillar at the site. Credit:
    Klaus Schmidt/German Archaeological Institute.

    Carving a comet impact?

    Just a handful of the giant circular and oval rooms at Gobekli Tepe have been excavated so far, but surveys show many more are still buried underground at the site. Each of these round rooms is defined by a ring of hulking T-shaped pillars.

    Most of the pillars feature ornate carvings of animals, like snakes, foxes, wild boars, birds, and other critters. Individual rooms also usually have one particular animal as its theme, which is why researchers suggested that the ancient hunter-gatherers were so-called animalists. They believed all living creatures had spirits, and they worshiped them.

    Although many of the pillars focus on just a single animal, other carvings combine their art into a more complex motif. Gobekli Tepe’s Pillar 43 is the most prominent of these. This captivating pillar appears to feature a large vulture, other birds, a scorpion, and additional abstract symbols.

    “We don’t know what the meanings of these symbols are,” Schmidt said, but he suggested they might depict architectural buildings.

    Whatever their meaning, archaeologists say the carvings are masterful reliefs repeated many times over, implying the work of trained craftsman who not only knew what the animals were supposed to look like, but also had the technical ability to recreate them.

    Although Pillar 43 remains a mystery, Klaus’ team believes that one thing is clear about the pillars in general: They were built in a T-shape as a kind of stylized human form, like a person without a head. (Some others have even gone as far as to suggest the people who worshiped at the temple were a kind of skull cult, like later peoples in the region who removed heads from buried bodies to employ them in rituals.)

    “This T-form is really some unique phenomenon of this culture of Gobekli Tepe and the surrounding settlements, and it’s not repeated anywhere else on our Earth and in any other culture,” Schmidt said at a Gobekli Tepe research symposium in 2012. So, unlocking their meaning could help explain the entire site.

    And although the archaeologists who have spent decades excavating Gobekli Tepe may not be willing to make bold speculations about the original meaning of Pillar 43, that hasn’t stopped others.

    5
    Scientists have long debated whether a massive impact caused an Ice Age climate swing. Recently researchers discovered a crater buried beneath Greenland that may be the smoking gun for the theory. This image shows the topography under the site at Hiawatha glacier, mapped with airborne radar data (1997 to 2014, NASA; 2016 Alfred Wegener Institute). Black triangles and purple circles are elevated peaks around the rim and center. Dotted red lines and black circles show locations of additional sampling. Credit: Kjæer et al. / Science Advances.

    In 2017, a pair of chemical engineers made global headlines when they claimed that they were able to connect animal carvings on Gobekli Tepe’s pillars to the positions of various groups of stars in Earth’s sky many millennia ago.

    In a paper published in the journal Mediterranean Archaeology and Archaeometry, they argue that the so-called Vulture Stone carved on Pillar 43 is a “date stamp” for a catastrophic comet strike 13,000 years ago. This idea gained a lot of attention because scientists already suspected a comet struck Greenland around this time, potentially triggering the Younger Dryas period.

    “It appears Gobekli Tepe was, among other things, an observatory for monitoring the night sky,” Martin Sweatman, a chemical engineer at the University of Edinburgh and the study’s lead author, said in a media release. “One of its pillars seems to have served as a memorial to this devastating event — probably the worst day in history since the end of the Ice Age.”

    But again, the team of archaeologists who are actually excavating Gobekli Tepe aren’t buying it.

    “Assuming such a long tradition of knowledge relating to an unconfirmed (ancient) cosmic event appears extremely far-fetched,” the authors said in their rebuttal. “The assumption that asterisms [familiar star patterns] are stable across time and cultures is not convincing,” they added. “It is highly unlikely that early Neolithic hunters in Upper Mesopotamia recognized the exact same celestial constellations as described by ancient Egyptian, Arabian, and Greek scholars, which still populate our imagination today.”

    ‘Fingerprints of the gods’

    But these claims are far from the most extreme being made about Gobekli Tepe and the people who built it.

    Graham Hancock is the popular author of Fingerprints of the Gods. It’s a pseudoscience book that proposes, without evidence, that a mysterious ancient culture thought the ability to track the precession of the stars was so important they embedded a series of crucial numbers into great stories to ensure the knowledge was passed through generations. He calls it a “ghostly fingerprint of an advanced scientific knowledge impressed on the oldest myths and traditions of our planet.”

    One of his favorite examples is Gobekli Tepe. In a 2015 interview on the Joe Rogan Experience that’s been viewed more than 11 million times, Hancock called Gobekli Tepe a “profoundly astronomical site.”

    Hancock’s ideas have helped fuel the surge of interest in Gobekli Tepe as an ancient observatory. But he has an even more fantastical claim about the vulture and other carvings on Pillar 43. He believes, again without evidence, that it’s an ancient constellation diagram that shows the winter solstice against a backdrop of today’s modern sky.

    “This is spooky and eerie,” Hancock said, “because it appears there’s overwhelming evidence that the people who made Gobekli Tepe had a profound knowledge of precession. And it appears that they deliberately sent forward into time — in this time capsule — a picture of the sky in our age.”

    The details of his ideas only get more fantastical as he explains them, but that hasn’t stopped Hancock from getting huge amounts of attention for voicing them. And as a result, Gobekli Tepe has been swept up into pseudo-scientific claims and strange putdowns about what “mainstream archaeologists want the public to believe.”

    In the meantime, German archaeologist Klaus Schmidt, who discovered the site and led its excavation, died in 2014. But despite that loss, Schmidt’s team is continuing their decades-long dig at Gobekli Tepe, focusing on finding out who built the site and why.

    And although there is still no convincing evidence that Gobekli Tepe was built as an astronomical site, that doesn’t mean nothing will ever come to light. Perhaps, proof of Gobekli Tepe’s proposed connection to the stars is still buried, just beneath the sand.

    See the full article here .


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Astronomy is a magazine about the science and hobby of astronomy. Based near Milwaukee in Waukesha, Wisconsin, it is produced by Kalmbach Publishing. Astronomy’s readers include those interested in astronomy and those who want to know about sky events, observing techniques, astrophotography, and amateur astronomy in general.

    Astronomy was founded in 1973 by Stephen A. Walther, a graduate of the University of Wisconsin–Stevens Point and amateur astronomer. The first issue, August 1973, consisted of 48 pages with five feature articles and information about what to see in the sky that month. Issues contained astrophotos and illustrations created by astronomical artists. Walther had worked part time as a planetarium lecturer at the University of Wisconsin–Milwaukee and developed an interest in photographing constellations at an early age. Although even in childhood he was interested to obsession in Astronomy, he did so poorly in mathematics that his mother despaired that he would ever be able to earn a living. However he graduated in Journalism from the University of Wisconsin Stevens Point, and as a senior class project he created a business plan for a magazine for amateur astronomers. With the help of his brother David, he was able to bring the magazine to fruition. He died in 1977.

     
  • richardmitnick 12:22 pm on September 9, 2020 Permalink | Reply
    Tags: "Baja quakes highlight seismic risk in northern Mexico", , , , , Geology, , ,   

    From temblor: “Baja quakes highlight seismic risk in northern Mexico” 

    1

    From temblor

    September 8, 2020
    By Hector Gonzalez-Huizar, Ph.D. and John M. Fletcher, Ph.D., Centro de Investigación Científica y Educación Superior de Ensenada, Baja California (CICESE).

    On the morning of Monday August 17, 2020, a magnitude-5.1 earthquake struck Baja California, Mexico. The mainshock originated approximately 78 miles (126 kilometers) south of the USA-Mexico border and 62 miles (100 kilometers) southeast from Ensenada, Mexico. USGS “Did you feel it?” reports indicate that shaking occurred throughout northern Baja and southern California. Like almost any other geologic event, earthquakes do not recognize international borders.

    1
    The Agua Blanca fault forms a valley in northern Baja California. Credit: John M. Fletcher.

    Faults in Baja

    Most of the main faults in southern California can be traced into Baja California. These faults are primarily the result of the relative plate motion along the boundary between the North American and the Pacific tectonic plates. The main fault separating these plates — the San Andreas Fault — stretches through southern California, where it becomes the Imperial Fault south of the Salton Sea. In northern Mexico it continues as the Cerro Prieto Fault before it dives into the Gulf of California. Motion between the Pacific and North American plates is not limited to this series of faults. Throughout southern California and Baja, a network of faults accommodates a broad zone of movement known as the Southern California Shear Zone.

    2
    Map showing the location of the main faults (f) and fault systems (f.z.) in southern California, (USA) and northern Baja California (Mexico), and the epicenter of some of the earthquakes referred.

    A history of seismicity

    The faults in Baja California are seismically active and have the potential to generate large magnitude earthquakes that could affect communities on both sides of the international border. The magnitide-7.1 El Mayor-Cucapah earthquake struck northeastern Baja California on April 4, 2010, activating a series of previously unmapped faults in the Sierra Cucapah and southern portion of the Colorado River Delta.

    The earthquake was widely felt throughout northwest Mexico and southern California. Cities close to the epicenter, like Calexico and Mexicali, experienced violent shaking. Four people died and approximately 100 were injured. It is estimated that around 25,000 people were affected. Many other faults in Baja California are capable of generating large magnitude earthquakes. For example, in 1931 a magnitide-7.1 earthquake occurred on the Cerro Prieto Fault. In 1892 a magnitide-7-7.5 earthquake occurred on the Laguna Salada Fault. In 1956 a magnitide-6.8 earthquake originated on the San Miguel-Vallecitos fault. It is estimated that the Agua Blanca Fault has the capacity to generate earthquakes as large as magnitide-7.3.

    Recent earthquakes activated multiple faults

    The August 17 magnitude-5.1 earthquake and its aftershock sequence occurred near the projected region of intersections of four major fault systems including the Agua Blanca, Tres Hermanas, San Miguel-Vallecitos and San Pedro Martir faults. All of these faults extend over 100 km in length and lose displacement near the region of intersection. The complexity in the region of intersection, characterized by a series of NE and NW trending faults, appears to be the result of the variability in the directions and rate of displacement of the four major faults.

    3
    Map of the area inside the small square in Fig 1. White lines represent main faults, including the projection of the Tres Hermanas (TH), San Miguel-Vallecitos (SM) and Agua Blanca (AB) faults. Green star marks part of the rupture area of the 1956 (magnitude-6.8) earthquake. Circles represent the epicenters of the magnitude-5.1 August 17, 2020 earthquake (yellow), its foreshock and aftershocks (red).

    A magnitude-4.7 foreshock occurred 21 minutes before the magnitude-5.1. Two weeks after the mainshock, over 200 aftershocks were identified and located by the seismic network operated by the Ensenada Center for Scientific Research and Higher Education (CICESE), the institution responsible for monitoring and investigating the seismicity along the Baja California Peninsula and the Gulf of California. At least three of these aftershocks were greater than magnitude-4.0.

    4
    Graph showing the magnitude of the magnitude-5.1 earthquake (yellow), its foreshock (magnitude-4.7) and aftershocks, as function of time relative to the magnitude-5.1 earthquake.

    Most of the aftershock sequence occurred along a southwest-northeast trending line that extends 4 miles (7 kilometers). The surface exposure of a fault lies parallel to this line 1-2 miles (2-3 kilometers) to the west. These aftershocks suggest this fault surface is tilted moderately to the east at depth. We call this fault the Cardenas Fault.

    Interestingly, at least 10 aftershocks define a second, roughly perpendicular line that extends approximately 2.5 miles (4 kilometers) and coincides with several smaller faults in the same orientation.

    This bimodal aftershock distribution suggests that the magnitude-5.1 quake activated at least two perpendicular faults with a total rupture length of 7 miles (11 kilometers). It is unclear on which of these faults the magnitude-5.1 originated. The focal mechanisms (or beach ball) of an earthquake is obtained from seismograms in order to define the orientation of two orthogonal planes, one of which corresponds to the orientation of the fault where the earthquake originates. In the case of the magnitude 5.1 quake one of these planes is consistent with the San Miguel Fault and the other plane with the Cardenas Fault. Thereafter, the earthquake might have initiated on any of these two faults.

    5
    Focal mechanisms obtained for the magnitude-5.1 earthquake, which suggest that the earthquake originated on either the Cardenas or the San Miguel faults. Both of these faults seem to be activated by this event.

    The northeast oriented Cardenas Fault, which was activated in this event, links the San Miguel and Tres Hermanas faults to the north with the Agua Blanca Fault to the south, each of which are major faults capable of generating much larger earthquakes. If the magnitude-5.1 quake occurred on the left-lateral Cardenas Fault, it should unclamp the southeasternmost sections of the San Miguel and Tres Hermanas Fault making them more susceptible to failure in the future. The shift toward failure should be greater on the Tres Hermanas Fault because it is oriented almost perpendicular to the Cardenas Fault.

    International collaboration in Baja

    Earthquake researchers at CICESE collaborate with scientists at institutions in California and worldwide. However, given that earthquakes do not respect international boundaries, we are convinced that stronger collaborations and data sharing between CICESE and research institutions in the USA will result in a better understanding of the earthquakes and their potential impact on the communities on both sides of the border.

    Further Reading

    Castro, R. R., A. Mendoza-Camberos, and A. Pérez-Vertti (2018). The broadband seismological network (RESBAN) of the Gulf of California, Mexico, Seismol. Res. Lett. 89, no. 2A, doi: 10.1785/ 0220170117.

    Cruz-Castillo, M. (2002) Catálogo de fallas regionales activas en el norte de Baja California, México, GEOS 22 (1), 37-42.

    Doser, D. I., (1992). Faulting processes of the 1956 San Miguel, Baja California earthquake sequence, Pageoph, 139 (1) 2-16.

    Gonzalez-Huizar, H. (2019) La Olimpiada XXIV de Ciencias de la Tierra: Los Grandes Terremotos de México, GEOS, 39 (1).

    Hauksson, E., Stock, J., Hutton, K. et al. The 2010 M w 7.2 El Mayor-Cucapah Earthquake Sequence, Baja California, Mexico and Southernmost California, USA: Active Seismotectonics along the Mexican Pacific Margin (2010). Pure Appl. Geophys. 168, 1255–1277. https://doi.org/10.1007/s00024-010-0209-7.

    Plattner, C., R. Malservisi, T. H. Dixon, P. LaFemina, G. F. Sella, J. Fletcher, F. Suarez-Vidal (2007), New constraints on relative motion between the Pacific Plate and Baja California microplate (Mexico) from GPS measurements, Geophysical Journal International, 170 (3), 1373–1380, https://doi.org/10.1111/j.1365-246X.2007.03494.x.

    Vidal-Villegas, J. A., L. Munguía, J. A. González-Ortega, M. A. NuñezLeal, E. Ramírez, L. Mendoza, R. R. Castro, and V. Wong (2018). The northwest México seismic network: Real-time seismic monitoring in north Baja California and northwestern Sonora, México, Seismol. Res. Lett. 89, no. 2A, doi: 10.1785/0220170183.

    See the full article here .


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Earthquake Alert

    1

    Earthquake Alert

    Earthquake Network project

    Earthquake 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
    1

    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

     
  • richardmitnick 4:48 pm on September 4, 2020 Permalink | Reply
    Tags: After a big quake ends the tectonic plates that meet at the fault boundary settle into a go-along- get-along phase., , Deep underground forces explain quakes on San Andreas Fault", , , Earthquake physics, Geology, Gradually motion across chunks of granite and quartz- the Earth's bedrock- generates heat due to friction., Most of California seismicity originates from the first 10 miles of the crust but some tremors on the San Andreas Fault take place much deeper., , , Quakes of magnitude 6 have shaken the Parkfield section of the fault at fairly regular intervals in 1857; 1881; 1901; 1922; 1934; 1966; and 2004 according to the USGS., , , When friction pushes temperatures above 650 degrees Fahrenheit the rock blocks grow less solid and more fluid-like.   

    From University of Southern California via phys.org: “Deep underground forces explain quakes on San Andreas Fault” 

    USC bloc

    From University of Southern California

    via


    phys.org

    1
    Credit: Unsplash/CC0 Public Domain.

    Rock-melting forces occurring much deeper in the Earth than previously understood appear to drive tremors along a notorious segment of California’s San Andreas Fault, according to new USC research that helps explain how quakes happen.

    The study from the emergent field of earthquake physics looks at temblor mechanics from the bottom up, rather than from the top down, with a focus on underground rocks, friction and fluids. On the segment of the San Andreas Fault near Parkfield, Calif., underground excitations—beyond the depths where quakes are typically monitored—lead to instability that ruptures in a quake.

    “Most of California seismicity originates from the first 10 miles of the crust, but some tremors on the San Andreas Fault take place much deeper,” said Sylvain Barbot, assistant professor of Earth sciences at the USC Dornsife College of Letters, Arts and Sciences. “Why and how this happens is largely unknown. We show that a deep section of the San Andreas Fault breaks frequently and melts the host rocks, generating these anomalous seismic waves.”The newly published study appears in Science Advances. Barbot, the corresponding author, collaborated with Lifeng Wang of the China Earthquake Administration in China.

    The findings are significant because they help advance the long-term goal of understanding how and where earthquakes are likely to occur, along with the forces that trigger temblors. Better scientific understanding helps inform building codes, public policy and emergency preparedness in quake-ridden areas like California. The findings may also be important in engineering applications where the temperature of rocks is changed rapidly, such as by hydraulic fracturing.

    Parkfield was chosen because it is one of the most intensively monitored epicenters in the world. The San Andreas Fault slices past the town, and it’s regularly ruptured with significant quakes. Quakes of magnitude 6 have shaken the Parkfield section of the fault at fairly regular intervals in 1857, 1881, 1901, 1922, 1934, 1966 and 2004, according to the U.S. Geological Survey. At greater depths, smaller temblors occur every few months.So what’s happening deep in the Earth to explain the rapid quake recurrence?

    Using mathematical models and laboratory experiments with rocks, the scientists conducted simulations based on evidence gathered from the section of the San Andreas Fault extending up to 36 miles north of—and 16 miles beneath—Parkfield. They simulated the dynamics of fault activity in the deep Earth spanning 300 years to study a wide range of rupture sizes and behaviors.

    The researchers observed that, after a big quake ends, the tectonic plates that meet at the fault boundary settle into a go-along, get-along phase. For a spell, they glide past each other, a slow slip that causes little disturbance to the surface.

    But this harmony belies trouble brewing. Gradually, motion across chunks of granite and quartz, the Earth’s bedrock, generates heat due to friction. As the heat intensifies, the blocks of rock begin to change. When friction pushes temperatures above 650 degrees Fahrenheit, the rock blocks grow less solid and more fluid-like. They start to slide more, generating more friction, more heat and more fluids until they slip past each other rapidly—triggering an earthquake.

    “Just like rubbing our hands together in cold weather to heat them up, faults heat up when they slide. The fault movements can be caused by large changes in temperature,” Barbot said. “This can create a positive feedback that makes them slide even faster, eventually generating an earthquake.”

    It’s a different way of looking at the San Andreas Fault. Scientists typically focus on movement in the top of Earth’s crust, anticipating that its motion in turn rejiggers the rocks deep below. For this study, the scientists looked at the problem from the bottom up.

    “It’s difficult to make predictions,” Barbot added, “so instead of predicting just earthquakes, we’re trying to explain all of the different types of motion seen in the ground.”

    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

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    USC campus

    The University of Southern California is one of the world’s leading private research universities. An anchor institution in Los Angeles, a global center for arts, technology and international business, USC’s diverse curricular offerings provide extensive opportunities for interdisciplinary study, and collaboration with leading researchers in highly advanced learning environments. With a strong tradition of integrating liberal and professional education, USC fosters a vibrant culture of public service and encourages students to cross academic as well as geographic boundaries in their pursuit of knowledge.

     
  • richardmitnick 4:13 pm on September 1, 2020 Permalink | Reply
    Tags: "Probing the origin of the mantle’s chemically distinct 'scars'", , , During its evolution our planet separated into distinct layers—core; mantle; and crust., , Geology, Plate tectonic processes allow for continuous evolution of the crust and play a key role in our planet’s habitability., Some of the elements found in crustal rocks don’t play nicely with the mantle’s minerals., The composition of Earth’s mantle was more shaped by interactions with the oceanic crust than previously thought., When continental crust formation draws minerals out of the mantle they leave behind a depleted residue.   

    From Carnegie Institution for Science: “Probing the origin of the mantle’s chemically distinct ‘scars'” 

    Carnegie Institution for Science
    From Carnegie Institution for Science

    August 31, 2020

    The composition of Earth’s mantle was more shaped by interactions with the oceanic crust than previously thought, according to work from Carnegie’s Jonathan Tucker and Peter van Keken along with colleagues from Oxford that was recently published in Geochemistry, Geophysics, Geosystems.

    1
    Basalt, the most-common rock on Earth’s surface, encases green crystals–a geologic “nesting doll” phenomenon called a xenolith. Basalts such as this one derive from a section of the mantle that has been depleted in incompatible trace elements, which is usually attributed to continental crust formation. In their work, Tucker and his collaborators propose another mechanism that would impart this signature.

    2

    During its evolution, our planet separated into distinct layers—core, mantle, and crust. Each has its own composition and the dynamic processes through which these layers interact with their neighbors can teach us about Earth’s geologic history.

    Plate tectonic processes allow for continuous evolution of the crust and play a key role in our planet’s habitability. Earth has two kinds of tectonic plates: those that host continents, which have survived for billions of years, and those that are mostly covered by oceans. Oceanic plates are created by the upward motion of mantle material that occurs when plates spread apart. They are destroyed by sliding under continental plates and back into the mantle, a process that also forms new continental crust.

    “The chemical composition of the mantle is influenced by continent formation and geoscientists can read chemical markers left behind by this process,” Tucker explained.

    For example, some of the elements found in crustal rocks don’t play nicely with the mantle’s minerals. When continental crust formation draws these elements out of the mantle, they leave behind a depleted residue, like sucking the juice out of a Sno-Cone and leaving just ice. This is referred to as crust extraction and is usually thought to create “scars” that are easy to spot and identify in rocks. It also leaves behind distinct zones in the mantle that are depleted of these particular elements.

    “It’s long been thought that these chemical scars are the product of crust formation,” Tucker explained. “But mantle’s inaccessibility means that it’s difficult to know for sure using rock and mineral samples alone.”

    To probe the question of the origin of these depleted reservoirs in the mantle, Tucker, van Keken, and their Oxford colleagues Rosemary Jones and Chris Ballentine developed a new model, which showed that the “scar-forming” process of sequestering of incompatible elements from the rest of the mantle is occurring not just in the crust but independently in the deep mantle thanks to old oceanic plates that were drawn all the way down.

    “Our work demonstrates that the processes determining the mantle’s composition are more complicated than we previously thought,” Tucker concluded.

    This work was supported by the U.S. NSF and the J NERC Deep Mantle Volatiles consortium.

    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.

    Carnegie 6.5 meter Magellan Baade and Clay Telescopes located at Carnegie’s Las Campanas Observatory, Chile. over 2,500 m (8,200 ft) high


    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

     
  • richardmitnick 10:37 am on September 1, 2020 Permalink | Reply
    Tags: "The world’s deepest freshwater cave just got a whole lot deeper", , Czech Republic’s Hranice Abyss which stretches farther below ground than any other freshwater cave system., , Geology,   

    From Science Magazine: “The world’s deepest freshwater cave just got a whole lot deeper” 

    From Science Magazine

    Aug. 31, 2020
    Charlotte Hartley

    1
    In 2016, researchers estimated the depth of the Hranice Abyss to be 473.5 meters.
    Marcin Jamkowski/AP.

    For decades, spelunkers have flocked to the flooded caverns of the Czech Republic’s Hranice Abyss, which stretches farther below ground than any other freshwater cave system. Now, a scientific campaign to the cave has revealed it is 1 kilometer deep, more than twice as deep as previously thought. The researchers also say the abyss formed as groundwater seeped down from the surface, not as water percolated up, as previously believed—a finding that could call into question the origin of other deep caves.

    The abyss sits in karst, a Swiss cheese–like terrain formed when soluble rock such as limestone is slowly dissolved by water. Most caves form from the surface downward, when water from rain or melted snow—slightly acidic from dissolved carbon dioxide—makes its way underground, eating into rock and creating cracks that widen over time. However, deep caves can also form from the bottom up, when acidic groundwater heated by Earth’s mantle burbles up. Researchers believed the Hranice Abyss was in this second category because its waters contain carbon and helium isotopes that come from deep inside Earth.

    The Hranice Abyss is the world’s deepest freshwater cave.

    2
    Polish explorer Krzysztof Starnawski is seen in this underwater photo taken Aug. 15, 2015 in the flooded Hranicka Propast, or Hranice Abyss, in the Czech Republic. He is seen exploring the limestone abyss and preparing for deeper exploration with the use of a remotely-operated underwater robot, or ROV. (Krzysztof Starnawski of EXPEDITION via AP.)

    But it is not the deepest overall. That honor belongs to Georgia’s Veryovkina Cave, a 2.2-kilometer-deep incursion formed when sea levels in the neighboring Black Sea dropped dramatically millions of years ago.

    3
    Georgia’s Veryovkina Cave. National Geographic.

    In 2016, researchers using a remotely operated vehicle estimated the Hranice Abyss to be 473.5 meters deep. However, the vehicle’s fiber optic communication cable kept it from going deeper, and the true extent of the cave system remained a mystery.

    Now, scientists have revealed a clearer picture using a combination of geophysical techniques. First, they gathered data from an aboveground array of electrodes that measured how easily the limestone conducted electricity—which can indicate regions of rocks or gaps. Next, they used sensors to look for tiny variations in the tug of gravity, which can reveal caverns. Finally, they recorded the reflections of seismic waves produced by setting off small explosive charges, a way of producing a rough underground map.

    The resulting picture revealed a system of deep, trenchlike caverns—some filled with sediment—that had been carved from the limestone, says geophysicist Radek Klanica of the Czech Academy of Sciences, who led the study. Surprisingly, these sediment-covered trenches extend to about 1 kilometer below the surface—far deeper than previous estimates, the team reported this month in the Journal of Geophysical Research: Earth Surface. That new depth could bolster the appeal for tourists, Klanica says, which is “especially important” for the economy. But it also offers new insights into the local geology, which could have wider implications for maintaining water supplies in the region.

    Klanica and his colleagues also found evidence of an ancient groundwater drainage system in the limestone, suggesting a new, aboveground origin for the abyss. The underground trenches aligned with mountains on one side and a deep basin on the other. Water would have run from the mountains into the ancient basin, carving out caverns from the top downward. The researchers think additional upwelling of water from below may have occurred later, explaining the presence of carbon and helium isotopes. Klanica says this means scientists may need to reconsider the origins of other deep caves supposedly formed from the bottom up, such as Lagoa Misteriosa in Brazil, or Boesmansgat in South Africa.

    Francesco Sauro, a geologist at the University of Bologna who was not involved in the study, praises the team’s use of multiple geophysical methods. “It’s a good example of how you should do things,” he says. The new estimated depth of the abyss is “impressive,” he adds. “It could be that other caves have the same story, or that [similarly formed] caves could be even deeper.” Sauro is also curious about what types of living organisms scientists might find in the depths of the cave system: “We don’t know exactly what could be down there.”

    See the full article here .


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

     
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