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  • richardmitnick 12:11 pm on January 3, 2019 Permalink | Reply
    Tags: Anak Krakatau Volcano Sunda Strait Indonesia, , , Vulcanology   

    From Science Alert: “Here’s Why ‘The Child of Krakatau’ Is Still Extremely Dangerous” 

    ScienceAlert

    From Science Alert

    3 JAN 2019
    THOMAS GIACHETTI

    1
    (Byelikova_Oksana/iStock)

    On Dec. 22 at 9:03 pm local time, a 64-hectare (158-acre) chunk of Anak Krakatau volcano, in Indonesia, slid into the ocean following an eruption. This landslide created a tsunami that struck coastal regions in Java and Sumatra, killing at least 426 people and injuring 7,202.

    Satellite data and helicopter footage taken on Dec. 23 confirmed that part of the southwest sector of the volcano had collapsed into the sea. In a report on Dec. 29, Indonesia’s Center of Volcanology and Geological Hazard Mitigation said that the height of Anak Krakatau went from 338 meters (1,108 feet) above sea level to 110 meters (360 feet).

    My colleagues and I published a study [Lyell Special Publications] in 2012 looking at the hazards this site posed and found that, although it was very difficult to forecast if and when Anak Krakatau would partially collapse, the characteristics of the waves produced by such event were not totally unpredictable.

    Landslide-triggered

    Although most tsunamis have a seismic origin (for example, the Sumatra, Indonesia one in 2004 and at Tohoku, Japan in 2011), they may also be triggered by phenomena related to large volcanic eruptions.

    Tsunamis caused by volcanoes can be triggered by submarine explosions or by large pyroclastic flows – a hot mix of volcanic gases, ash and blocks travelling at tens of miles per hour – if they enter in a body of water.

    2
    A simulation of an Anak Krakatau volcanic event shows waves of 15 meters or more locally (in red). (Giachetti et al. 2012)

    Another cause is when a large crater forms due to the collapse of the roof of a magma chamber – a large reservoir of partially molten rock beneath the surface of the Earth – following an eruption.

    At Anak Krakatau, a large, rapidly sliding mass that struck the water led to the tsunami. These types of events are usually difficult to predict as most of the sliding mass is below water level.

    These volcanic landslides can lead to major tsunamis. Landslide-triggered tsunamis similar to what happened at Anak Krakatau occurred in December 2002 when 17 millions cubic meters (600 millions cubic feet) of volcanic material from Stromboli volcano, in Italy, triggered a 8-meter-high wave.

    More recently in June 2017, a 100-meter-high wave was triggered by a 45-million-cubic-meter (1.6-billion cubic-feet) landslide in Karrat Fjord, in Greenland, causing a sudden surge of seawater that wreaked havoc and killed four people in the fishing village of Nuugaatsiaq located about 20 km (12.5 miles) away from the collapse.

    These two tsunamis had few fatalities as they occurred either in relatively isolated locations (Karrat Fjord) or during a period of no tourist activity (Stromboli). This was obviously not the case at Anak Krakatau on Dec. 22.

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    Satellite pictures taken before (left) and after (right) the Anak Krakatau eruption. (Geospatial Information Authority of Japan/CC BY-NC-ND)

    Child of Krakatau

    This part of the world is well-experienced with destructive volcanoes. In August 26-28, 1883, Krakatau volcano experienced one of the largest volcanic eruptions ever recorded in human history, generating 15 meter (50 feet) tsunami waves and causing more than 35,000 casualties along the coasts of the Sunda Strait in Indonesia.

    Nearly 45 years after this 1883 cataclysmal eruption, Anak Krakatau (“Child of Krakatau” in Indonesian) emerged from the sea in the same location as the former Krakatau, and grew to reach about 338 meters (1,108 feet), its maximum height on Dec. 22, 2018.

    Many tsunamis were produced during the 1883 eruption. How they were generated is still debated by volcanologists, as several volcanic processes may have acted successively or together.

    I worked on this very problem in 2011 with my colleagues Raphaël Paris and Karim Kelfoun from the Université Clermont Auvergne in France, and Budianto Ontowirjo from the Tanri Abeng University in Indonesia.

    However, the short time left in my postdoctoral fellowship had me shift direction away from the 19th-century explosion to focus on Anak Krakatau. In 2012, we published a paper entitled “Tsunami Hazard Related to a Flank Collapse of Anak Krakatau Volcano, Sunda Strait, Indonesia” [Link is above].

    This study started with the observation that Anak Krakatau was partly built on a steep wall of the crater resulting from the 1883 eruption of Krakatau. We thus asked ourselves “what if part of this volcano collapses into the sea?”

    To tackle this question, we numerically simulated a sudden southwestwards destabilization of a large part of the Anak Krakatau volcano, and the subsequent tsunami formation and propagation. We showed results projecting the time of arrival and the amplitude of the waves produced, both in the Sunda Strait and on the coasts of Java and Sumatra.

    When modeling landslide-triggered tsunamis, several assumptions need to be made concerning the volume and shape of the landslide, the way it collapses (in one go versus in several failures), or the way it propagates. In that study, we envisioned a somewhat “worst-case scenario” with a volume of 0.28 cubic kilometers of collapsed volcanic material – the equivalent of about 270 Empire State buildings.

    We predicted that all the coasts around the Sunda Strait could potentially be affected by waves of more than 1 meter less than 1 hour after the event.

    Unfortunately, it seems that our findings were not that far to what happened on Dec. 22: The observed time of arrival and amplitude of the waves were in the range of our simulation, and oceanographer Stephan Grilli and colleagues estimated that 0.2 cubic kilometers of land actually collapsed.

    Since the landslide occurred, there have been continuous Surtseyan eruptions. These involve explosive interactions between the magma of the volcano and the surrounding water, which is reshaping Anak Krakatau as it continues to slowly slide to the southwest.

    Indonesia remains on high alert as officials warn of potentially more tsunamis. As people wait, it’s worth returning to studies that have looked at the potential hazards caused by volcanoes.

    See the full article here .


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  • richardmitnick 2:50 pm on December 26, 2018 Permalink | Reply
    Tags: , Lava Clues Chronicled Kīlauea’s Unusual 2018 Eruption, Vulcanology   

    From Eos: “Lava Clues Chronicled Kīlauea’s Unusual 2018 Eruption” 

    From AGU
    Eos news bloc

    From Eos

    12.26.18
    Ilima Loomis

    Samples from Kīlauea volcano’s extraordinary eruption that began last May could offer important insights into the behavior of volcanoes and the underlying mantle.

    1
    In this 2015 photo, a scientist from the Hawaiian Volcano Observatory collects a molten lava sample from Kīlauea using a rock hammer. Volcanologists in Hawaii and elsewhere often brave blistering heat and other hazards to gather fresh lava samples for research and to monitor lava properties that can foretell how hot and fluid subsequent flows may be. This monitoring helps authorities plan emergency responses. Credit: U.S. Geological Survey.

    “Imagine the hottest oven you can, sticking your head in—and it’s hotter than that,” volcanologist Cheryl Gansecki said, recounting what it felt like to approach active lava flows at Hawaii’s Kīlauea volcano, where the sheer volume of lava made the radiant heat extremely intense. “I’ve had a couple of times when I’ve tried to sample from a flow and just couldn’t. It just felt like everything was going to catch on fire.”

    When explosive blasts and spattering lava made it too dangerous to approach the flow, scientists got as close as they could and then waited, added Gansecki, a volcanologist at the University of Hawai‘i at Hilo. “You’re watching for [a piece of lava spatter] to fall kind of close to you, then running in and grabbing it and running out again.” To lock the sample into the chemical state it was in when it was collected, geologists would cool the searing blob of molten rock quickly by “quenching” it in a bucket of water. The plunge froze it into glass, preventing the chemical alterations and crystallization that would occur if the lava cooled slowly.

    Grabbing fresh lava was one of the first things that volcano scientists did when fissures in Leilani Estates, an area on Kīlauea’s eastern flank that is historically less volcanically active than other areas, suddenly and dramatically began spewing lava in what became a long-unseen type of eruption on 3 May.

    For the previous 35 years, the volcano had been reliably releasing lava from a vent called Pu‘u O‘o that lies 21 kilometers (13 miles) from those newly opened fissures. In the 46-second video below, a Hawaiian Volcano Observatory (HVO) geologist scoops up and quenches a bucket’s worth of lava last year from that Pu‘u O‘o vent.

    Building a Rock Record

    As dangerous as lava samples are to retrieve, they provide valuable rewards. For one, lab studies of the traits of the fresh, glassy volcanic rock can give clues to what’s coming next in an eruption. Most critically for public safety, from the time the volcano abruptly changed on 3 May, volcanologists watched for chemical clues that younger, hotter lava was arriving on the scene. Such markers mean the eruption is about to become much faster and more voluminous. Such a change requires emergency crews to deploy more quickly and widely and possibly to carry out additional evacuations.

    Other markers may take longer to decipher and require painstaking research to interpret. These markers, researchers told Eos, often come with a more enduring reward: a deeper understanding of the volcano itself and perhaps of volcanism in general.

    2
    Bags of Kīlauea lava samples await analysis on a lab bench at HVO this past June. Volcanologists collected the samples from the lower East Rift Zone, where many fissures opened unexpectedly in the spring and summer. Sitting in the lab is USGS HVO geologist Lopaka Lee. Credit: Leslie Gordon, U.S. Geological Survey

    Now that Kīlauea has settled down, a history of what transpired remains, written in stone. Over the late spring and summer, HVO teams amassed bag after bag of volcanic rubble, some of it drawn hot from fresh flows, some scoured from tree branches spat upon by the eruption, more just picked up from the ground after it had rained down, and some chipped from solidified flows.

    In the heat of what many are calling a once-in-a-lifetime event, scientists were driven to build a collection of lava samples whose chemistry could help tell the story of the volcano’s historic transformation. They raced against time to capture samples of new lava before yet another variety of lava came along and obliterated all traces of what had surfaced not long before.

    A Surprising Sample

    As a batch of magma sits in the ground under a volcano, it begins to cool. As it cools, certain minerals precipitate out as crystals, leaving behind a liquid that is richer in the remaining elements and depleted of the elements in the crystallized minerals. Volcanologists call this aged magma “differentiated” or “evolved.”

    Gansecki works mostly as a laboratory researcher analyzing samples, including many of those captured from Kīlauea’s outpourings. She measures the concentrations of trace elements to determine whether a lava sample is fresh or evolved—and if it is evolved, just how evolved it might be.

    In the early days of the eruption, HVO scientists noticed that the erupting lava was very evolved, indicating that it had been sitting under the ground for several years. This isn’t so unusual: New eruptions often start by pushing old magma out of the pipes. The scientists watched the lava closely, looking for signs of fresh magma entering the system. Finally, after 10 days, they saw a change. But it wasn’t the change they expected. Instead of being fresher, this material was actually more evolved than what they had previously seen—significantly more.

    The sample, which had a sticky, paste-like consistency when it gunked out of the ground, had extremely high levels of zirconium, an element that becomes concentrated in magma as it differentiates.

    Gansecki had never seen zirconium at those levels before. “My first thought was that this was an error—there’s something wrong with the machine,” she said. “The next sample came in and was even higher. We were like, ‘Wow. This is real.’”

    3
    Scientists collect different types of lava for analysis, including already solidified material in the field like these pieces chipped from lava that overflowed the fissure 8 channel in Kīlauea’s lower East Rift Zone on 2 August. Credit: U.S. Geological Survey

    The zirconium levels were twice as high as samples taken from other fissures in the Leilani Estates eruption and 4 times higher than lava from Pu‘u O‘o. Gansecki’s lab also measured levels of rubidium, strontium, yttrium, and niobium: four trace elements that provide clues to magma’s age and origins. “All five of [these elements] told us the same story: ‘This is something you’ve never seen before.’”

    Andesite Sighted

    HVO scientists sent the samples to a lab on the U.S. mainland to test the lava’s silica content, a measurement used to classify lava types. Those results showed that what was erupting out of fissure 17 was not basalt, the kind of lava that usually erupts from Kīlauea, but silica-rich andesite. Although there is a record of some lava from the 1800s with silica that approached andesite-like levels, it’s the first time that full andesite has been observed at Kīlauea, U.S. Geological Survey (USGS) officials said.

    “This would certainly be rare for Kīlauea,” said Aaron Pietruszka, an isotope geochemist with USGS in Denver. The more interesting question is how the lava that appears to be andesite formed, he added. “That will tell us a lot about how Kīlauea works.”

    A more detailed chemical analysis and comparison to other lavas from the eruption and past eruptions could help answer the question.

    3
    Fast, hot lava flows like these pouring from fissure 8 in the lower East Rift Zone in June streamed along channels 100 to 300 meters wide, destroying homes and vegetation, until reaching the ocean at Kapoho Bay. Credit: U.S. Geological Survey

    One reason the eruption has produced such evolved lavas might be because the area where it was located, called the lower East Rift Zone, isn’t very volcanically active, with decades passing between eruptions. Past eruptions in the area occurred in 1955 and 1840. “It’s a poorly studied part of Kīlauea, because there are relatively few eruptions,” Pietruszka said.

    (Not long after the suspected andesite spurted out, the fresher, hotter magma that scientists had been predicting did, in fact, arrive, bringing with it the faster, more voluminous and destructive flows many had feared.)

    “It would be good to get a better idea of basic questions, like how much magma is actually stored in the lower East Rift Zone underground, how frequently does magma reach the lower East Rift Zone from the summit. We don’t know,” he added.

    Chemical Fingerprints

    To pin down the time and place a batch of magma comes from, Pietruszka looks at the abundance of trace elements, as well as four different lead isotopes. “Those characteristics are thought to be mainly inherited from changes going on in the mantle,” he said. “They act like compositional tracers. Fingerprints.”

    That’s because the mantle itself is heterogeneous, made of different materials swirled together. The composition of mantle melt rising to Earth’s surface reflects those differences on a scale of kilometers, Pietruszka said. “When you look at lava coming out of Mauna Loa [a Hawai‘i Island volcano that last erupted in 1984], Kīlauea, and Loihi (an active volcano on the ocean’s floor about 35 kilometers east of Hawai‘i Island), they are all different from each other,” he said.

    Within a single volcano, those differences can show up over a timescale of decades. Looking at the chemistry of different eruptions and comparing their volumes of lava can offer insights into fluctuations in magma supply being delivered to the volcano from the mantle, he said. That could help explain the extent to which eruptions are driven by fluctuations within the mantle versus geological activity closer to the surface.

    “Going forward, an important question to decipher is, Was this new activity on the lower East Rift Zone driven partly by the delivery of a new batch of mantle-derived magma to the volcano?” he said. “If it was, we should see the chemical and isotopic fingerprints of the lava change over time (at the new eruption) to be different from what was previously erupting at Puʻu ʻŌʻō.”

    Archiving an Eruption

    Kīlauea’s latest activity was a remarkable change in the behavior of one of the best-studied volcanoes in the world, scientists say. The transformation included a sudden, violent shift in the location and volume of eruption from the volcano’s flank and a dramatic subsidence at Kīlauea’s summit as the magma reservoir beneath the mountain drained.

    Satellites, seismometers, and other instruments monitored these changes. Ultimately, lava chemistry is expected to provide vital clues into how the events played out beneath the ground.

    5
    Satellite photos taken before (left) and after (right) the destruction wrought by the recent Kīlauea eruption in the Leilani Estates residential neighborhood. Fissuring and high-volume flows originated in this area, particularly from fissure 8, whose cone appears at center right. Lava also buried and incinerated other neighborhoods on its way to the sea. Credit: U.S. Geological Survey

    Gansecki said that scientists have built an archive for future study, moving quickly to recover lava samples before they were buried by subsequent flows. “All those early results are buried already, they’re gone,” she said. “So this is the only record we have.”

    It’s a record that will be studied by volcanologists for years to come, Pietruszka predicted. The lava’s chemical composition offers clues to what’s going on inside the volcano, he said, including how magma changes chemically over time, what Kīlauea’s internal structure might look like, and maybe even what’s taking place much deeper down, in the mantle of Earth.

    “We can look at these chemical fingerprints and trace the different magma batches as they move through the plumbing system of the volcano,” he said.

    USGS geophysicist Michael Poland said that lessons learned from the recent eruption could be applied to similar volcanoes around the world. Volcanologists will combine what they learn about the chemistry of Kīlauea’s erupted products with geophysical data and other findings to create new models for how the volcano works. “I think we’re going to learn more about the properties of magma and magma transport from this,” he said.

    These studies are much more than an academic exercise: This year’s eruption of Kīlauea destroyed 716 homes. Thus, scientists have a responsibility to make as much headway as they can from the sample archive and other observations, Poland said. “This eruption is giving us an opportunity to learn a lot more about how the volcano works, but it’s coming at a tremendous cost to the people who live in that part of the island,” he said while the eruption was still underway. “So I think we owe it to those people to take every lesson we can from this event.”

    See the full article here .

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  • richardmitnick 2:14 pm on June 17, 2018 Permalink | Reply
    Tags: , , , Vulcanology   

    From EarthSky: “Kilauea volcano lava river flows to sea” 

    1

    From EarthSky

    June 17, 2018
    Adam Voiland/NASA Earth Observatory

    Kilauea volcano’s Fissure 8 has produced a large, channelized lava flow that’s acted like a river, eating through the landscape, finally producing clouds of steamy, hazardous “laze” as hot lava meets the cold ocean.

    Steaming fissures in the Kilauea volcano first began to crack open and spread lava across Hawaii’s Leilani Estates neighborhood on May 3, 2018. Since then, more than 20 fissures have opened on the Kilauea’s Lower East Rift Zone, though most of the lava flows have been small and short-lived.

    Not so for Fissure 8. That crack in the Earth has been regularly generating large fountains of lava that soar tens to hundreds of feet into the air. It has produced a large, channelized lava flow that has acted like a river, eating through the landscape as it flows toward the sea.

    1
    Photo shows Fissure 8 of Kilauea volcano in Hawaii. Fissure 8 fountains reached heights up to 160 feet overnight on Friday. The USGS Hawaiian Volcano Observatory reports that fragments falling from the fountains are building a cinder-and-spatter cone around the vent. USGS image taken June 12, 2018, around 6:10 a.m. HST. View the latest images and videos via USGS.

    While the Fissure 8 lava flow initially remained in relatively narrow channels, it began to widen significantly as it neared the coastline and passed over flatter land. It evaporated Hawaii’s largest lake in a matter of hours, and devastated the communities of Vacationland and Kapoho, destroying hundreds of homes [which probably should never have been built there. Lessons unlearned also in the New Jersey shore communities].

    2
    May 14, 2018. Image via NASA.

    3
    June 7, 2018. Image via NASA.

    On June 3, 2018, lava from Fissure 8 reached the ocean at Kapoho Bay on Hawaii’s southeast coast. When the Multi-Spectral Instrument (MSI) on the European Space Agency’s Sentinel-2 satellite captured a natural-color image on June 7 (top image, above), the lava had completely filled in the bay and formed a new lava delta.

    ESA/Sentinel 2

    For comparison, the Landsat 8 image shows the coastline on May 14 (lower image, above).

    3
    June 15, 2018, photo of Fissure 8. This fissure has produced a lava fountain pulsing to heights of 185 to 200 feet (55 to 60 meters). Spattering has built a cinder cone that partially encircles Fissure 8, now 170 feet (51 meters) tall at its highest point. The steam in the foreground is the result of heavy morning rain falling on warm (not hot) tephra (lava fragments).

    Since May 3, 2018, Kilauea has erupted more than 110 million cubic meters of lava. That is enough to fill 45,000 Olympic-sized swimming pools, cover Manhattan Island to a depth of 7 feet (2 meters), or fill 11 million dump trucks, according to estimates from the U.S. Geological Survey (USGS). However, that is only about half of the volume erupted at nearby Mauna Loa in a major eruption in 1984.

    The new land at Kapoho Bay is quite dynamic, fragile, and dangerous. USGS warns:

    “Venturing too close to an ocean entry on land or the ocean exposes you to flying debris from sudden explosive interaction between lava and water.”

    Since lava deltas are built on unconsolidated fragments and sand, the loose material can abruptly collapse or quickly erode in the surf.

    4
    This thermal map shows the fissure system and lava flows as of 5:30 p.m. on Saturday, June 9, 2018. The flow from fissure 8 remains active, with the flow entering the ocean at Kapoho. The black and white area is the extent of the thermal map. Temperature in the thermal image is displayed as gray-scale values, with the brightest pixels indicating the hottest areas. Image via USGS.

    The plumes that form where lava meets seawater are also hazardous. Sometimes called laze, these white plumes of hydrochloric acid gas, steam, and tiny shards of volcanic glass can cause skin and eye irritation and breathing difficulties.

    5
    The ocean entry remains fairly broad with a white steam/laze plume blowing onshore. USGS image taken June 15, 2018.

    See the full article here .


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  • richardmitnick 9:45 am on May 30, 2018 Permalink | Reply
    Tags: , , , Vulcanology   

    From UCLA Newsroom: “On Hawaiian research trip, UCLA students got early look at Kilauea eruption” 


    From UCLA Newsroom

    May 25, 2018
    Joy McCreary

    The geological abnormalities they observed were collected as part of a long-term research effort.

    1
    This U.S. Geological Survey photo from May 22 shows how the fissure complex remains active in Kīlauea volcano’s lower east rift zone.

    About two months ago, a group of UCLA geophysics students watched fountains of bright red-orange lava at Kilauea volcano as they erupted from Halemaumau crater. At the time, the volcano was another fascinating and beautiful geological feature to study. Since then, however, Kilauea has become much more active, and more dangerous.

    Spurred on by more than 100 earthquakes that followed the magnitude 6.9 earthquake on May 5, more than 20 fissures have opened up along the western coast of the big island of Hawaii sending lava into surrounding neighborhoods. On May 17, an explosion sent ash 30,000 feet into the sky as magma interacted with the water table. More than 1,800 residents have been evacuated from Leilani Estates and Lanipuna Gardens, and the governor has declared a state of emergency.

    [For some reason, the U.S.A. citizenry continues to build in areas not fit for building. It is the same on the New Jersey USA shoreline.]

    Even at the time of their trip in March, Paul Davis, professor of geophysics at UCLA who led the excursion, and his students noticed abnormalities in their observations.

    “The increased activity we did witness was part of the build-up to the activity we’re seeing now,” Davis said. He added that the kind of research he and his students conducted on the trip can help scientists learn more about how to predict eruptions like this.

    “We need to understand magma pathways, in order to interpret the way Earth’s surface is deformed and that can help us determine where and when the magma will break out on the surface,” said Davis, who has been studying volcanoes and plate tectonics for 30 years to better understand geology on other planets.

    2
    Jewel Abbate, left, and Aaron Tannenbaum. Fiona McCarthy/UCLA

    The lava, which has destroyed several dozen structures, has been erupting since May 3. The problem has only continued to worsen, and as Davis pointed out, it’s uncertain how long this will continue.

    “I am deeply saddened by the destruction of people’s homes from the recent eruption. The research that is done on the volcano is intended to help better understand what is happening and hopefully predict paths that flows might take,” said Fiona McCarthy, a third-year geophysics major who was one of the 11 students who went.

    Davis and researchers at UCLA have been taking measurements across a dike — a vertical sheet of rock that is a result of magma fracturing the surrounding rock and intruding into the crack, which causes the dikes to resemble veins throughout rock formations — formed in 1973. UCLA geophysics classes made similar trips in 1995 and 1997. Taking measurements helps researchers understand the geophysics of an erupting volcano and provides long term data to compare Hawaii with other planets, and in particular, Mars.

    The most recent trip was the beginning of a quarter-long capstone course, and the culmination of a geophysics degree at UCLA. In the past, students have also been to the San Andreas Fault on the Carrizo Plain in central California; Long Valley Caldera, near Yosemite; an area that stretches from Acapulco on the Pacific coast to Tampico on the Gulf coast of Mexico; the Andes in Peru; and Mount Etna in Sicily, trips partly funded by generous donations. Students were able to put all of their theoretical knowledge into practice as they traversed volcanoes and hiked through the Hawaiian forests to gather data.

    “I was able to finally actually see field work being done, collect data, and now I am fitting models that I have read about for the past couple years to that data. That’s pretty incredible to see,” McCarthy said. “This definitely feels like what I will be doing in the future if I do end up going to grad school or even just out in the workforce.”

    The typical daily schedule mirrored that of a working geophysicist, she said. They would wake up at 6 a.m. for breakfast at 7 on a military base, and then the group would head out for the day hiking to lava fields or driving to the top of Mauna Loa, the largest active volcano on Earth.

    3
    View of Halemaumau crater on Kilauea volcano’s summit at the end of March before it filled with lava and overflowed.

    While in the field, the UCLA students would take readings with a variety of tools and devices. They used very-low-frequency electromagnetic meters and magnetometers to study the Earth’s magnetic fields. They also used self potential probes to measure the electrical potential in Earth’s minerals and gravimeters to monitor the difference in the force of gravity from one place to another. Once they returned to camp in the evenings, the team would upload their data to their computers.

    “The very-low-frequency electromagnetic meter and self potential probes helped us understand what was going on with the water table under the surface. Gravity measurements were taken over Mauna Loa to see how the volcano might affect Earth’s gravity. The magnetometer measured Earth’s magnetic field locally at the volcano to see how it may perturb Earth’s magnetic field,” fourth-year geophysics major Aaron Tannenbaum said.

    According to Davis, part of the uncertainty with how eruptions will continue is the nature of lava itself. When it’s underground (and referred to as magma), it progresses unevenly to the surface. Also, he said, eruptions can be episodic rather than continuous due to blockages or changes in the Earth’s surface.

    “Some conduits are blocked and it takes time for the pressure to build and break the blockage,” Davis said. “Water can seep in from a crater lake or the water table and cause stream generation and pressurization. Water seeping in from the water table at Halemaumau is thought to have caused the May 17 ash eruption of Kilauea.”

    Studying the current eruptions will provide extremely valuable data on the geophysical conditions that occur before a new eruption, Davis said. For example, radar images from satellites show how the ground deformed because of magma intrusion and the magnitude 6.9 earthquake on May 5.

    4
    Students and faculty from UCLA Earth, planetary and space sciences at Hawaiian Volcano Observatory. UCLA.

    Students will spend the remainder of the quarter comparing the measurements from Hawaii to Olympus Mons on Mars. Both the volcanoes demonstrate similar anomalies and studying both volcanoes will help further understand and prepare for future eruptions.

    Taking geophysics students into the field is the best way to prepare students for a myriad of opportunities, whether they are hoping to study natural disasters like volcanic eruptions and earthquakes, to work at NASA studying other planets and exoplanets, to search for resources, or to monitor Earth’s environment. According to Davis field experience, along with data analysis, comparison with theory and hypothesis testing, is the best preparation for such future pursuits.

    “The problem-solving skills I have learned from the day we got on the plane until now are priceless, and I am sure there are plenty more lessons to learn and lots more coding to do,” McCarthy said.

    See the full article here .


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  • richardmitnick 9:11 am on May 24, 2018 Permalink | Reply
    Tags: , , Bárðarbunga volcano in Iceland, , Magma Flow in a Major Icelandic Eruption, Vulcanology   

    From Eos: “Magma Flow in a Major Icelandic Eruption” 

    From AGU
    Eos news bloc

    From Eos

    5.23.18
    Sarah Stanley

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    Lava erupts from a fissure in the Holuhraun lava field during the 2014 eruption of Bárðarbunga volcano in Iceland. New research reveals how tectonic forces contributed to the underground flow of magma before it erupted. Credit: GISBA/iStock

    Iceland straddles a short stretch of the spreading boundary between the North American and Eurasian tectonic plates. New research by Spaans and Hooper [Journal of Geophysical Research: Solid Earth] explores how mechanical stress caused by the two plates moving apart contributed to magma emplacement during an eruption of Bárðarbunga volcano in late August of 2014.

    Researchers have long had a general understanding of the eruption’s mechanics: Two weeks beforehand, magma began traveling underground away and upward from the ice-covered crater of the volcano in a formation known as a dike. Cutting through the existing rock above, the dike traveled roughly northeast for 50 kilometers before stopping beneath the Holuhraun lava field in central Iceland.

    Within days, lava began to erupt from a fissure in the lava field. For 6 months, the fissure released record-breaking amounts of sulfur dioxide gas and more lava than had been produced by any other Icelandic eruption in the past 200 years—1.6 cubic kilometers in total.

    Although previous research Nature Geoscience has revealed this detailed timeline of the dike’s path, the mechanisms underlying its formation have been unclear. The researchers investigated the interaction between two factors that helped open the dike and extend it: pressure from the magma flow itself and existing stress from the two tectonic plates pulling away from each other.

    To explore this interaction, the researchers constructed a mathematical, mechanical model of dike formation. They based their approach on a previously developed method that keeps the model computationally manageable by considering only relevant boundaries, like dike walls and magma chamber walls, instead of modeling a much larger volume of rock.

    The model used measurements of changes to Earth’s surface that occurred during the eruption, which can hint at what happened underground. Some of these changes were detected in radar images of Earth’s surface captured by satellites in a method known as interferometric synthetic aperture radar (InSAR). Other data came from 31 global navigation satellite system (GNSS) stations positioned around the volcano; slight changes in their relative positions indicate surface changes.

    The approach revealed that tectonic forces contributed significantly to formation of the dike at the final, northern stretches of its path. However, the magnitude of tectonic stress was much lower along the dike’s initial path away from the volcanic crater, where magma pressure dominated its formation.

    These findings suggest that earlier, undetected volcanic activity within the past 50 years released tectonically induced stress near the caldera, whereas stresses farther north were left unrelieved until the 2014 eruption. Past activity could easily have gone unnoticed because it occurred beneath the Vatnajökull ice cap, and sensitive monitoring equipment was only recently introduced to the area.

    In addition to shedding light on the past, the ability to model and understand eruptions like this one could aid efforts to predict when and where lava may erupt in the future. For instance, this new research suggests that a new dike arising from the same crater may not necessarily travel in the same direction and would likely erupt closer to the crater itself.

    See the full article here .


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  • richardmitnick 9:02 pm on May 18, 2018 Permalink | Reply
    Tags: , Kilauea erupts sending ash 30000 feet high, , , , Vulcanology   

    From temblor: “Kilauea erupts, sending ash 30,000 feet high” 

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    From temblor

    May 17, 2018
    David Jacobson

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    While today’s eruption at the summit of Kilauea sent ash 30,000 feet high, no immediate damage has been reported. This is in start contrast to what is still happening to the east of Kilauea, where fissures have destroyed dozens of homes. This picture shows one of the erupting fissures near Pahoa, Hawaii, on May 6. (Picture from: Bruce Omori/EPA)

    The most explosive eruption yet

    At just past 4 a.m. this morning local time, Hawaii’s Kilauea Volcano erupted, sending ash over 30,000 feet into the sky, and began drifting northeast. This eruption comes two days after the aviation code was elevated from orange to red. Following the eruption, the USGS Hawaiian Volcano Observatory issued an advisory that, “At any time, activity may again become more explosive, increasing the intensity of ash production and producing ballistic projectiles near the vent.” While ash is expected to spread across the area close to the volcano, it does not pose a significant risk to, and residents are being advised to remain in shelters if they are in the path of the ash cloud.

    Today’s eruption is the most explosive in a series of events that began on May 3. However, there are fears that an even larger eruption could take place at one of the world’s most active volcanoes in the coming weeks to months. Part of the concern is that the lava lake at the summit of Kilauea is dropping significantly. As this happens, the lava will fall below the water table, and large boulders, some the size of cars will fall into the vent, blocking the opening. Then, as lava interacts with the water, steam is created, and explosive events can occur. Such events are called phreatic eruptions. It is not known yet if today’s eruption was a phreatic event.

    Likely not a life-threatening situation

    Fortunately, a steam-driven event would likely not pose significant risk to life, as the largest boulders, often called bombs, would only be cast in the immediate vicinity of the crater. However, damage could still occur as marble-sized rocks could still be cast up to 10 miles. Because of this, and to protect tourists and residents, Hawaii Volcanoes National Park has been closed since last Thursday.

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    This figure from The New York Times shows what is currently happening at the summit of Kilauea and how a steam-induced (phreatic) eruption could occur. Such an event could eject volcanic bombs the size of cars. (Figure from: The New York Times)

    How long could this last?

    Even though today’s eruption was the largest since increased activity began on May 3, it only lasted a few minutes. Nonetheless, continued emissions from the crater are still reaching 12,000 feet. For some, this is not impacting their daily lives, as people continue to play golf (see below). However, people are being advised to take caution as increased levels of volcanic air pollution (vog) have been noted around the Big Island, and there is still the possibility of a larger eruption.

    3
    For some, the volcanic activity at Kilauea, on Hawaii’s Big Island hasn’t even impacted their ability to play golf.

    In addition to the eruptions at the summit of Kilauea, smaller fissure eruptions continue in the Lower East Rift Zone. This is the area around Leilani Estates, where dozens of homes have already been consumed by slow-moving ‘a’a lava flows. In total, nearly 2,000 people have been evacuated from their homes, as there are now 20 fissures which have opened up. Unfortunately, if past events can help us predict what will happen, it is unlikely things will slow down for some time, as in 1955, similar activity commenced for 88 days. Therefore, it is possible that residents will continued to be rattled and subjected to continuous volcanic eruptions for some time.

    4
    This map from the USGS shows the fissures in the East Rift Zone which started opening on May 3. As of now, 20 fissures have opened, and dozens of homes have been destroyed.

    References [ Sorry, no links]
    USGS
    New York Times
    Forbes
    CNN
    NBC News

    See the full article here .

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    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 12:37 pm on May 12, 2018 Permalink | Reply
    Tags: , , , Vulcanology   

    From EarthSky: “Hawaii’s erupting Kilauea volcano” 

    1

    From EarthSky

    Eleanor Imster
    Deborah Byrd

    Kilauea is one of the world’s most active volcanoes. Here are images and video from its ongoing eruption in Hawaii.

    4
    The Verge 6 days ago

    7
    The lava lake at the summit of Kilauea, via @USGSVolcanoes on Twitter.

    1
    NASA’s Terra satellite acquired this image on May 6, 2018. Massive sulfur dioxide plumes from Kilauea volcano are shown here in yellow and green. A smaller, but thicker, sulfur dioxide gas plume can be seen coming from Kilauea. The prevailing trade winds blow the plumes to the southwest, out over the ocean. Image via NASA/METI/AIST/Japan Space Systems/Japan ASTER Science Team.

    NASA/Terra satellite

    2
    Looking up the slope of Kilauea, a shield volcano on the island of Hawaii. Puu_Oo_looking_up_Kilauea.jpg

    UPDATE May 12, 2018 from the Hawaiian Volcano Observatory/ USGS: Volcanic unrest in the lower East Rift Zone of Kilauea Volcano continues. While no lava has been emitted from any of the 15 fissure vents since May 9, earthquake activity, ground deformation, and continuing high emission rates of sulphur dioxide indicate additional outbreaks of lava are likely. The location of future outbreaks is not known with certainty, but could include areas both uprift (southwest) and downrift (northeast) of the existing fissures, or resumption of activity at existing fissures. Communities downslope of these fissures could be at risk from lava inundation.

    Lava and sulfur dioxide gas are continuing to spew from Kilauea volcano on Hawaii’s Big Island, where flows of lava across a rural neighborhood have caused evacuations. By late Tuesday (May 8, 2018), some 104 acres were covered by lava. Hawaii Civil Defense said that 35 structures — including at least 26 homes — had been destroyed.

    A total of 12 volcanic fissures had formed as of late Tuesday. Residents were voicing frustration and anxiety against a backdrop of flowing lava and hazardous fumes.

    May 4, 2018 Third Leilani Eruption from Mick Kalber on Vimeo.

    Videographer Mick Kalber was on the ground in Leilani Estates on May 5, where he told captured the dramatic video above and told this story:

    “This is a killer video! And may be one of the last ground level shots I’ll be able to get before I have to evacuate … After all the lava drained out of the Pu’u ‘O’o Vent (the main vent of the 35 year long current eruption) last Monday [April 30, 2018], the contents moved down the East rift zone, causing hundreds of earthquakes as far away as Kapoho, some 15 miles downslope. All week, a new eruption had been forecast … cracks appeared on roadways, as the Earth began to swell. And then, on Thursday afternoon [May 3, 2018], Pele (the Volcano Goddess) made her appearance in the lower part of Leilani Estates Subdivision. At first, fountains of lava shot up into the air … but within a few hours, she had settled down into a lava flow that now threatens dozens of nearby homes, and a geothermal power plant just a quarter mile downslope. That flow has now stopped… but several more continue to pop out nearby. I live in the subdivision, and we are continually experiencing rolling earthquakes … it ain’t over till it’s over!”

    Meanwhile, the video below, also from Mick Kalber, shows the view from the air:

    May 6, 2018 HUGE Fissure Eruption from Mick Kalber on Vimeo.

    The eruptive activity began on April 30, 2018, when the floor of Kilauea’s crater began to collapse. Earthquakes followed, including one that measured magnitude +6.9, a very strong earthquake. All the while, lava was being pushed into new underground areas that eventually broke through the ground in such areas as the Leilani Estates (population 1,560 at the 2010 census) near the town of Pahoa, Hawaii.

    Evacuations in Leilani Estates began on May 4.

    The USGS is doing a good job following the volcano on Twitter.

    Follow @UGSGVolcanoes on Twitter.

    Kilauea is one of the world’s most active volcanoes, and it’s the youngest and southeastern-most volcano on Hawaii’s Big Island. Eruptive activity along the East Rift Zone has been continuous since 1983.

    Bottom line: Images from the May 2018 eruption of Kilauea volcano on Hawaii’s Big Island.

    See the full article here .

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    Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. “Being an EarthSky editor is like hosting a big global party for cool nature-lovers,” she says.

     
  • richardmitnick 8:04 am on May 3, 2018 Permalink | Reply
    Tags: , , , , Vulcanology   

    From University of Illinois via EarthSky: “Ample warning for supervolcanos?” 

    U Illinois bloc

    University of Illinois

    EarthSky

    May 3, 2018
    Eleanor Imster

    3
    llinois geology professor Patricia Gregg, right, and graduate student Haley Cabaniss have developed the first quantitative model that could help predict supervolcano eruptions.
    Photo by L. Brian Stauffer

    1
    A supervolcano is a large volcano that has had an eruption of magnitude 8, which is the largest value on the Volcanic Explosivity Index (VEI). This means the volume of deposits for that eruption is greater than 240 cubic miles (1,000 cubic km). No image credit.

    No need to panic about an imminent supervolcano eruption, not from the Yellowstone supervolcano or another other similar system around the globe. That’s according to a new study published in the peer-reviewed journal Geophysical Research Letters on April 19, 2018. The study says that geological signs pointing to a catastrophic supervolcano eruption would be clear far in advance.

    Scientists had thought that these huge volcanoes gradually built up more and more molten rock until the pressure got to be too much. But they are now realizing that much of the period between eruptions — as much as a million years — is probably quiet. To help understand how to forecast supervolcano eruptions, a team of geologists quantified the effects of tectonic stress on the rocks that house these sleeping giants.

    Geologist Patricia Gregg of University of Illinois is a co-author on the study. She explained in a statement:

    “Supervolcanos tend to occur in areas of significant tectonic stress, where plates are moving toward, past or away from each other.”

    Haley Cabaniss, a PhD student at University of Illinois, is the study’s first author. Her work focuses on computer modeling of 3-D magma reservoirs of volcanos, in order to determine the how systems fail and ultimately. She explained how the models used in this study showed that tectonic stress does have a profound effect on the stability of supervolcanoes, but that these stresses aren’t the only factor to cause an eruption. She said:

    “Any tectonic stress will help destabilize rock and trigger eruptions, just on slightly different timescales. The remarkable thing we found is that the timing seems to depend not only on tectonic stress, but also on whether magma is being actively supplied to the volcano.”

    The researchers found that, in any given tectonic setting, the magma reservoirs inside supervolcanoes appear to remain stable for hundreds to thousands of years while new magma is being actively suppled to the system. Gregg said:

    “We were initially surprised by this very short timeframe of hundreds to thousands of years. But it is important to realize that supervolcanoes can lay dormant for a very long time, sometimes a million years or more. In other words, they may remain stable, doing almost nothing for 999,000 years, then start a period of rejuvenation leading to a large-scale eruption.”

    The researchers unexpectedly found that their models could help forecast supervolcano eruption timing and inform experts on what to expect, geologically, well before an eruption. Gregg acknowledged that people tend to panic whenever they hear that Yellowstone or, say, the Taupo Volcanic Zone in New Zealand, experience any change in seismic or geyser activity.

    3
    Bay of Plenty, North Island, New Zealand, from the Bay of Plenty coast to Mounts Tongariro, Ngauruhoe, and Ruapehu (at bottom of picture). Also shows Lake Taupo and the Rotorua Lakes. This scene was acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS), flying aboard NASA’s Terra satellite, on October 23, 2002.BayofPlentyA2002296.jpg

    NASA/Terra satellite

    But she said this new research suggests that the precursors to catastrophic eruption will be far greater and long-lasting than anything yet documented. She said:

    “When new magma starts to rejuvenate a supervolcano system, we can expect to see massive uplift, faulting and earthquake activity, far greater than the meter-scale events we have seen in recent time. We are talking on the range of tens to hundreds of meters of uplift. Even then, our models predict that the system would inflate for hundreds to thousands of years before we witness catastrophic eruption.”

    Cabaniss added:

    “It is also important to note that our research suggests that the whole rejuvenation-to-eruption process will take place over several or more human lifetimes. Our models indicate that there should be plenty of warning.”

    Bottom line: Before a supervolcano erupts, many warning signs will appear first, says a new study.

    See the full article here .

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  • richardmitnick 7:05 am on March 23, 2018 Permalink | Reply
    Tags: , , , , , , Radon Tells Unexpected Tales of Mount Etna’s Unrest, Vulcanology   

    From Eos: “Radon Tells Unexpected Tales of Mount Etna’s Unrest” 

    AGU
    Eos news bloc

    Eos

    22 March 2018
    Susanna Falsaperla
    Marco Neri
    Giuseppe Di Grazia
    Horst Langer
    Salvatore Spampinato

    Readings from a sensor for the radioactive gas near summit craters of the Italian volcano reveal signatures of such processes as seismic rock fracturing and sloshing of groundwater and other fluids.

    1
    Mount Etna in Sicily, Italy, spews lava from a Strombolian and effusive eruption on 24 April 2012. The church Santa Maria della Provvidenza stands in the foreground in the town of Zafferana Etnea on the mountain’s eastern flank. New research from a team studying the volcano finds that variations in its radon emissions provide insights into volcanic and tectonic influences inside the mountain and, for some seismic activity, up to tens of kilometers away. Credit: Marco Neri.

    Some researchers view radon emissions as a precursor to earthquakes, especially those of high magnitude [e.g., Wang et al., 2014; Lombardi and Voltattorni, 2010], but the debate in the scientific community about the applicability of the gas to surveillance systems remains open. Yet radon “works” at Italy’s Mount Etna, one of the world’s most active volcanoes, although not specifically as a precursor to earthquakes. In a broader sense, this naturally radioactive gas from the decay of uranium in the soil, which has been analyzed at Etna in the past few years, acts as a tracer of eruptive activity and also, in some cases, of seismic-tectonic phenomena.

    To deepen the understanding of tectonic and eruptive phenomena at Etna, scientists analyzed radon escaping from the ground and compared those data with measurements gathered continuously by instrumental networks on the volcano (Figure 1). Here Etna is a boon to scientists—it’s traced by roads, making it easy to access for scientific observation.

    2
    Fig. 1. Panoramic view of the volcano as it appeared during 2008 and 2009. No image credit.

    Dense monitoring networks, managed by the Istituto Nazionale di Geofisica e Vulcanologia, Catania-Osservatorio Etneo (INGV-OE), have been continuously observing the volcano for more than 40 years. This continuous dense monitoring made the volcano the perfect open-air laboratory for deciphering how eruptive activity may influence radon emissions.

    Tower of the Philosopher

    3
    Volcanologist Marco Neri during the winter of 2008–2009 downloads data onto a laptop from the ERN1 radon sensor at the site (later buried in lava) known as the Tower of the Philosopher. Behind him, less than 1 kilometer away, ash billows from the summit craters of the volcano. Credit: Marco Neri.

    In a recently published study [Falsaperla et al., 2017], we analyzed a period of dynamic and variable volcanic activity of Etna between January 2008 and July 2009. In those 19 months, the volcano produced seismic swarms, surface ground fractures, a vigorous lava fountain, and an eruption lasting 419 days.

    In short, the volcano delivered enough diverse behaviors to test whether radon detected by a station located near the top of Etna, at an altitude of about 3,000 meters, showed any patterns that matched eruptive behavior recorded by the networks. The station is at a place formerly known as the Torre del Filosofo (Tower of the Philosopher), which in 2013 became buried below meters of lava flows that completely changed the location’s appearance.

    The network’s data are plentiful and are related to physical occurrences, such as the vibrations produced by magma movements in the feed conduits, or so-called volcanic tremor, as well as the tremor source’s localization within the volcano; isolated seismic events or swarms; and ground fractures accompanying the opening of eruptive fissures and associated explosive and effusive events. We conducted an analysis of this enormous amount of data through a statistical-mathematical approach that revealed possible correlations and, in many cases, obvious synchronicities with radon emissions.

    What Did We Discover?

    Our study revealed that essentially two processes influenced radon levels at the monitoring station. The first, easily imaginable given the location of the measuring probe less than a kilometer from the summit craters of Etna, is linked to the rise of magma in the volcano’s central conduit. Short, intense radon bursts, which researchers refer to as gas pulses, occur when a carrier gas that conveys the radon to the surface also bursts from the volcano (Figure 2). In the area in question, this carrier consists mainly of water vapor that feeds the local fumarolic activity.

    4
    Fig. 2. Volcanic processes may have influenced the flux of radon recorded by the ERN1 probe during Mount Etna’s 2008–2009 flank eruption. Variations in magmatic activity could have caused gas pulses near the feeding dike, as well as the rapid increase in radon values recorded by the ERN1 station probe. Conceptual model by the authors (2017).

    The second process is rock fracturing from an earthquake or seismic swarm. Radon rising from rock fractures is a well-known, recurrent phenomenon caused by greater permeability of the ground following earthquake-induced breakage of rock.

    Action at a Distance

    We have also discovered that the radon probe of the Torre del Filosofo was sensitive even to relatively small earthquakes taking place several kilometers away. We noted a clear synchronism between seismic swarms more than 10 kilometers away from the probe and significant variations of radon, impossible to explain by the diffusion of radon gas to rocks and toward the surface. We therefore had to find a different solution, which we identified as a sloshing phenomenon, like the lapping of waves.

    Slosh dynamics describes the movement of liquids within a container [Ibrahim, 2005]. Experimental observations prove that sloshing may occur inside the conduits of volcanoes, promoting magma oscillations [Namiki et al., 2016].

    Applied to Etna, sloshing may explain how rock shaking induced by a seismic swarm can cause oscillatory motion in the groundwater and in the magmatic fluids contained within the volcano (Figure 3). These oscillations can propagate quickly inside the mountain, reaching far greater distances than had been imagined in relatively short times. Sloshing may also be favored by flank instability affecting the eastern and southeastern sectors of the volcano, as it can produce tensile stresses both on the summit and on the rift zones, increasing the permeability of the rocks in those areas [Acocella et al., 2016].

    5
    Fig. 3. Along with volcanic triggers (Fig. 2), tectonic activity may have influenced the flux of radon recorded by the ERN1 probe during Mount Etna’s 2008–2009 flank eruption. Seismicity in the rift zone could have caused microfracturing of the rocks, changing their porosity and permeability. Resulting gas migration inside the highly fractured zone related to the rift may have led to fluctuations in radon emissions recorded by the ERN1 station. Conceptual model by the authors (2017).

    In some ways, these remote influences are an unforeseen discovery that implicitly reveals that the volcano is in a perpetually precarious balance and therefore easily disturbed. Reminiscent of a butterfly effect, even a small phenomenon occurring, for example, on the north side of Mount Etna can make its effects felt on the opposite side.

    Acknowledgments

    We are grateful to Stephen Conway for his help in the English editing of this article. This work was supported by the Mediterranean Supersite Volcanoes (MED-SUV) project, which has received funding from the European Union’s Seventh Framework Programme for research, technological development, and demonstration under grant agreement 308665.

    References

    Acocella, V., et al. (2016), Why does a mature volcano need new vents? The case of the new Southeast Crater at Etna, Front. Earth Sci., 4, 67, https://doi.org/10.3389/feart.2016.00067.

    Falsaperla, S., et al. (2017), What happens to in-soil radon activity during a long-lasting eruption? Insights from Etna by multidisciplinary data analysis, Geochem. Geophys. Geosyst., 18(6), 2,162–2,176, https://doi.org/10.1002/2017GC006825.

    Ibrahim, R. A. (2005), Liquid Sloshing Dynamics: Theory and Applications, 948 pp., Cambridge Univ. Press, Cambridge, U.K., https://doi.org/10.1017/CBO9780511536656.

    Lombardi, S., and N. Voltattorni (2010), Rn, He and CO2 soil gas geochemistry for the study of active and inactive faults, Appl. Geochem., 25, 1,206–1,220, https://doi.org/10.1016/j.apgeochem.2010.05.006.

    Namiki, A., et al. (2016), Sloshing of a bubbly magma reservoir as a mechanism of triggered eruptions, J. Volcanol. Geotherm. Res., 320, 156–171, https://doi.org/10.1016/j.jvolgeores.2016.03.010.

    Wang, X., et al. (2014), Correlations between radon in soil gas and the activity of seismogenic faults in the Tangshan area, north China, Radiat. Meas., 60, 8–14, https://doi.org/10.1016/j.radmeas.2013.11.001.
    Author Information

    Susanna Falsaperla (email: susanna.falsaperla@ingv.it), Marco Neri, Giuseppe Di Grazia, Horst Langer, and Salvatore Spampinato, Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Catania, Italy

    See the full article here .

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  • richardmitnick 2:54 pm on February 20, 2018 Permalink | Reply
    Tags: , , Vulcanology   

    From Stanford University: “Stanford scientists eavesdrop on volcanic rumblings to forecast eruptions” 

    Stanford University Name
    Stanford University

    February 16, 2018
    Adam Hadhazy

    Sound waves generated by burbling lakes of lava atop some volcanoes point to greater odds of magmatic outbursts. This finding could provide advance warning to people who live near active volcanoes.


    Low frequencies produced by volcanoes could indicate an upcoming eruption. Jeffrey Johnson/ Boise State University.

    Scientists from Stanford and Boise State University analyzed the infrasound detected by monitoring stations on the slopes of the Villarrica volcano in southern Chile, one of the most active volcanoes in the world.

    1
    An aerial view of the Villarrica Volcano in Chile. Sarah and Iain

    The distinctive sound emanates from the roiling of a lava lake inside a crater at the volcano’s peak and changes depending on the volcano’s activity.

    The study, published Feb. 14 in the journal Geophysical Research Letters, demonstrated how changes in this sound signaled a sudden rise in the lake level, along with rapid up-and-down motions of the surging lake near the crater’s rim just ahead of a major eruption in 2015. Tracking infrasound in real time and integrating it with other data, such as seismic readings and gas emission, might help alert nearby residents and tourists that a volcano is about to blow its stack, the researchers said.

    “Our results point to how infrasound could aid in forecasting volcanic eruptions,” said study co-author Leighton Watson, a graduate student in the lab of Eric Dunham, an associate professor in the Department of Geophysics of the Stanford School of Earth, Energy & Environmental Sciences and also a co-author. “Infrasound is potentially a key piece of information available to volcanologists to gauge the likelihood of an eruption hours or days ahead.”

    Sleeping giant roars awake

    Villarrica is a picturesque mountain with an altitude of 9,300 feet. The snowcapped volcano looms over a lake and across from the city of Pucón, which swells to a quarter million people in the summer tourist season. At night, residents of Pucón can often see a scarlet glow from Villarrica’s lava lake, normally hidden well below the volcano’s rim.

    The ominous serenity that had held at Villarrica since its last eruption in the mid-1980s ended in the early morning hours on March 3, 2015. An incandescent fountain of lava rocketed from the mountaintop nearly a mile into the sky, spewing ash and debris and triggering bolts of lightning from the thick heat-generated clouds enveloping the summit. Around 4,000 people evacuated the immediate area. The eruption proved short-lived, however, and with risks of mudslides and flooding from melted snow minimal, evacuees soon returned to their homes.

    Infrasound monitoring stations established at Villarrica just two months before the 2015 event and maintained by co-author Jose Palma from the University of Concepcion in Chile captured its before-and-after sonic activity. Studying these data, the research team saw that in the build-up to the eruption, the pitch of the infrasound increased, while the duration of the signal decreased. Flyovers in aircraft documented the changes in Villarrica’s lava lake, allowing researchers to explore connections between its height and the sound generation.

    Watson offered a music analogy to explain this relationship. Similar to a person blowing into a trombone, explosions from gas bubbles rising and then bursting at the surface of the lava lake create sound waves. Just as the shape of a trombone can change the pitch of the notes it produces, the geometry of the crater that holds the lava lake modulates its sounds. When the lava lake is deep down in the volcano’s crater, the sound registers at a lower pitch or frequency – “just like when a trombone is extended,” said Watson. When the lava lake rises up in the crater, potentially heralding an eruption, the pitch or frequency of the sound increases, “just like when the trombone is retracted,” said Watson.

    Warning signs

    Future research will seek to tie infrasound generation to other critical variables in volcano monitoring and eruption forecasting, such as seismicity. Ahead of an eruption, seismic activity in the form of small earthquakes and tremors almost always increases. This seismicity emanates from several miles underground as magma moves through the volcano’s “plumbing system” of fractures and conduits that connect the volcano’s opening to magma chambers in our planet’s crust. Volcanologists think that changes in lava lake levels – and their attendant infrasound – result from the injection of new magma through volcanic plumbing, increasing the odds of a violent outburst.

    In this way, the collection of infrasound should prove beneficial for forecasting purposes at “open vent” volcanoes like Villarrica, where an exposed lake or channels of lava connect the volcano’s innards to the atmosphere. Closed vent volcanoes, however, where the pooling magma remains trapped under rock until an explosive eruption occurs, do not generate the same kind of infrasound and thus pose additional forecasting challenges. An example of a closed vent volcano is Mount St. Helens in southwestern Washington state, whose eruption in 1980 remains the most lethal and destructive eruption in the history of the United States.

    “Volcanoes are complicated and there is currently no universally applicable means of predicting eruptions. In all likelihood, there never will be,” Dunham said. “Instead, we can look to the many indicators of increased volcanic activity, like seismicity, gas emissions, ground deformation, and – as we further demonstrated in this study – infrasound, in order to make robust forecasts of eruptions.”

    Other co-authors include Jeffrey Johnson and Jacob Anderson of Boise State University.

    Funding was provided by the Fulbright Scholar Program, the National Science Foundation and the Chilean volcano monitoring authorities (OVDAS/SERNAGEOMIN).

    See the full article here .

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