From temblor: “Kīlauea starts new eruptive cycle with a lava show”

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From temblor

December 22, 2020 [Just tonight at temblor]

Megan Sever (@megansever4)

Kīlauea Volcano on the Big Island of Hawaii reawakened on Dec. 20 with a flourish, fountaining lava in its summit crater. Temblor talks with volcanologist Michael Poland about what the eruption means.

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On Dec. 20 at 9:30 p.m. local time, lava started flowing out of the walls of the Halema’uma’u crater at Kīlauea’s summit for the first time in more than two years. This photo was taken just before 5 a.m. on Dec 21. The main lava fountain height is about 18 meters (59 feet). Credit: USGS.

At 9:30 p.m. local time on Dec. 20, Kīlauea Volcano erupted for the first time since 2018. After seismicity ramped up about starting at approximately 8:30 p.m., lava broke out of the walls of Kīlauea’s summit crater, Halema’uma’u. The fresh lava vaporized the crater’s water lake, swapping it for a new lava lake on the crater floor. Fountains initially flowed out of three vents in the crater wall, filling the crater at a rate of several meters per hour. Don’t worry: Rates have slowed to about 1 meter, or approximately 3 feet, per hour and as of the morning of Dec. 22, the lava lake was still more than 480 meters, or approximately 1,600 feet below the crater rim. And even if the lava lake does eventually overflow, it will flow onto the summit caldera floor.

The volcano’s last eruption ended in 2018, after consistently erupting for 35 years. While much of that lengthy eruption had been fairly safe, with effusive lava flows at the ocean front and bubbling lava lakes in the Pu’u ‘Ō’ō cone and the summit, the increased activity in 2018 spectacularly disrupted life on the Big Island. From May through August 2018, Kīlauea erupted as much lava as it normally produces in 10 to 20 years. It opened up a couple of dozen new fissures, shot lava fountains more than 80 meters (260 feet) into the air, buried roads and destroyed some 700 homes. Then, it stopped.

At the end of the 2018 eruption, scientists thought that the magma reservoir that had been feeding the eruption had emptied like a deflated balloon, explaining why the eruption stopped. “We had speculated that the volume of magma that was in that reservoir was actually about what was erupted,” says volcanologist Michael Poland of the U.S. Geological Survey. But subsequent studies have suggested the massive eruption actually only drained a small fraction of the total volume of the reservoir, he says.

Kīlauea is one of the most active volcanoes on Earth and also one of the best instrumented. As such, scientists — and the world, thanks to the Hawaiian Volcano Observatory webcams — can see what’s happening at the volcano in real time.

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Scientists are continuously monitoring Kīlauea’s eruption. Credit: USGS.

On Dec. 21, Megan Sever spoke with Poland for Temblor Earthquake News about what Kīlauea’s latest rumblings mean for the volcano.

MS: Is this a continuation of 2018 eruption — was it not really finished? Or is this new?

MP: This is a new phase of activity. It’s clear that [after the 2018 eruption], we entered a different style of eruptive activity.

It’s quite exciting, because we’re seeing the volcano come back to life. And all of the datasets we can collect are going to tell us now about how the system at depth has changed since 2018. Is this stuff that’s coming out of the ground now brand new? Is it really fresh from the mantle, which might be suggested by the inflation? Is it maybe a mix of old and new? Or is it all old stuff? When we can look at the gas, the samples that we’re able to collect from spatter and Pele’s hair, and the deformation signals, I think we’re going to see a really neat story that allows us to look into the magma chamber and try to understand what happened over the two years that Kīlauea was dormant.

MS: Was it really dormant since 2018?

MP: It wasn’t quiet, but it wasn’t erupting. In about October 2018, we started seeing repeated deflation-inflation (DI) events. That’s where the summit deflates over the course of a day or two, and then suddenly inflates again. It’s a very small amount of deformation — you only see DI events on sensitive tiltmeters. But we had always tracked that back to the magma chamber that’s about a mile or so deep beneath the summit. Seeing these DI events start up again was a sign that the magma chamber wasn’t empty. There was still something in there that was able to change pressure.

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Hundreds of earthquakes struck the Big Island in just the last month, indicating that magma was moving at depth — a potential sign of an impending eruption. Credit: Temblor.

MS: Were there precursory signs of the current eruption?

MP: We knew very soon after the end of the 2018 activity that magma was still there. It just took a little while to pump up the system. We suspect that as soon as the 2018 eruption stopped, the volcano started to refill from beneath. By early 2019, it reached the point where it could pressurize the reservoir and push the ground up. In the last couple of months, we’ve really seen an increase in the rate of inflation of the volcano and also in the seismicity beneath the summit.

So it’s clear that things were really becoming pressurized. That’s going to culminate in either an intrusion … or an eruption. We had the intrusion on December 2. And then we had the eruption on December 20.

MS: Was this expected?

MP: Something like this was expected. It’s difficult to know the timing, of course. But we had seen Kīlauea inflating and refilling with magma since early 2019. So we knew that the system was recharging.

MS: What do we know about the magma chambers below Kīlauea?

MP: We know that there are at least two chambers and maybe three. There’s one that’s kind of ambiguous; it’s hard to tell how important and permanent it is. But there’s one reservoir that’s about 3 to 5 kilometers [approximately 2 to 3 miles] or so beneath the south part of the caldera. And then there’s a shallower reservoir that’s maybe 1 to 2 kilometers [approximately 0.6 to 1.25 miles] beneath the more central part of the caldera. And that’s the one that collapsed and drained in 2018. We believe they’re connected, but the connection is somewhat complex and difficult to work out.

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This schematic illustrates scientists’ understanding of the basic plumbing system below Kīlauea. Scientists think fresh magma is supplied from the mantle. Credit: Michael Poland, USGS.

MS:Does the magma just sit in these chambers and periodically erupt, then eventually fill up and erupt again? Where does Kīlauea’s lava come from?

MP: The ultimate source of Kīlauea’s magma is the mantle. There’s a melting anomaly that is feeding these volcanoes. But then some of it also is resident in the volcanoes. Some magma comes into the volcano and it sort of sits around and percolates and gets old. But some of the other magma is going to be very fresh. Looking at the composition of this stuff, we can get a sense of what we presume is fresh stuff coming in from the mantle. That should have a primitive, young signature in terms of its chemistry.
I’m very curious to see the proportion of new material versus old that erupted. I’m sure we’re seeing an influx of new stuff into the chamber — the inflation suggests that — but how much stuff does it have to mix with on the way up?

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Scientists — and the world, thanks to the Hawaiian Volcano Observatory webcams, which show the summit lava lake, as seen here in thermal imaging with a raft of cooler lava on top of fresh, hot magma — can see what’s happening at the volcano in real time. Credit: HVO.

MS: How do you determine the age of the erupted material without sampling the lava? I imagine sampling would be rather difficult right now!

MP: The lava samples are coming to us, because there’s Pele’s hair and [other volcanic] glasses that are coming off the eruption. We can just go and collect these samples on the ground outside of the eruption area. There will also be gas emissions. Really fresh magma is going to have a lot of gas in it because [the magma] won’t have sat around for a while and lost its gas. So the gas emission measurements will be important. And we can also look at where the deformation is coming from. It’s almost certainly the shallow magma body, but we may see other areas that were activated.

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Aerial view of the Kīlauea summit on Dec. 21, showing the two fissures pouring lava into the growing lava lake. As of the morning of Dec. 22, the lava lake had already filled 134 meters (440 feet) of the bottom of Halema’uma’u crater in the summit caldera. Credit: M. Patrick, USGS.

MS: How do we know if one of the rift zones is going to reactivate along with the summit?

MP: Well, we don’t know that any will. Traditionally, over the last few hundred years anyway, the bulk of the activity at Kīlauea has focused at the summit.

We sort of got used to the East Rift Zone [erupting], because starting in the 1950s, the rift zone was really active with lots of little eruptions and then the long one starting in 1983. But for the entirety of the 1800s, almost all of the eruptive activity was at summit. And even during the period of frequent rift zone eruptions in the 1950s through the early 1980s, there were many eruptions at the summit. So, a summit eruption is normal for Kīlauea. In fact, this one seems, at least at first, to be very similar to others that have lasted hours to days and pour lava into Halema’uma’u crater.

MS: Do we have any sense of whether this might be a days-long eruption or a years-long one? Is there anything in the signals that would give you any idea?

MP: Initially, we can look at the deformation. Ever since this eruption started, the volcano has been deflating, so it’s losing pressure. That depressurization is a sign that there’s more [magma] coming out than there is going into the magma chamber. If that continues, the volcano won’t be able to sustain the eruption anymore, because it will have dropped below some pressure threshold and it won’t be able to push the magma up the pipe anymore. We don’t know where that breakeven point is, but it’s a sign that this is probably not going to be a super long-term eruption.

Rather, what seems more likely is that we will get into a situation of cyclicity, typical of Kīlauea, where we would see inflation and then an eruption lasting hours to days. And it might be in the East Rift Zone or the summit. Then after it sort of bled off that pressure and deflated, it would go quiet for a while and begin to pressurize, inflate and pop again.

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One of the primary ways researchers know something is happening at depth is watching the data from tiltmeters. These tiltmeter data from the last month show pressure building at Kīlauea’s summit and then quickly deflating once it erupted on Dec. 20 (blue line). The green line shows very little occurring at the East Rift Zone. Credit: USGS.

MS: Are we seeing any evidence of magma moving throughout the system and possible eruptions in the East Rift Zone or elsewhere?

MP: There had been some evidence that the East Rift Zone was refilling, especially soon after the 2018 eruption ended. But after that initial activity, all the signals of recharge activity moved to the summit. We still struggle to understand what that East Rift Zone inflation signal was. But so far, it doesn’t look like anywhere else has been reactivated.

MS: Wasn’t the biggest recent earthquake, the magnitude-4.4, in the East Rift Zone? Can you explain that in terms of the summit eruption?

MP: Yeah, that’s interesting. The magnitude-4.4 appears to be on the large fault that underlies Kīlauea’s south flank. That fault is one of the reasons that there’s this southward motion of the entire volcano. It’s sort of sliding on the interface between the volcano and the underlying oceanic plate. And if you push that fault with a dike intrusion in the East Rift Zone, you tend to see strong earthquakes soon thereafter. In 2018, when that huge dike intruded into the East Rift Zone, it was followed by a magnitude- 6.9 earthquake. Similar situations occurred in 2011 and 2007.

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The 2020 eruption lies 15 kilometers from the magnitude-4.4 earthquake, the largest so far in this eruptive sequence. Credit: Temblor.

MS: Are the earthquakes causing the intrusions or the intrusions causing the earthquakes?

MP: We’ve seen it go both ways: that a dike intrusion in the East Rift Zone can push the South Flank Fault to break, and the South Flank Fault, moving away from the island, can pull open the rift zone. So they have this this interesting chicken-and-egg feedback going where they can activate one another.

What makes this case interesting is this was a summit eruption. I’m not familiar with summit eruptions commonly triggering felt seismicity right on the south flank. That may be that just because I haven’t studied that particular sort of thing. But I’m curious about the release. It makes you scratch your head a bit.

It’s also possible that it’s entirely coincidental. Although it seems to me a bit too coincidental. It feels like the summit pressurized, maybe pushed the South Flank Fault a bit, and it broke, causing this moderate earthquake.

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This map from 2010 shows the general south-southeast motion of Kīlauea along the South Flank Fault, at the interface between the volcano and the underlying oceanic plate. Continues GPS sites (arrows) show the motion. Credit: Michael Poland, USGS.

MS: Do you expect the seismicity to continue?

MP: As the volcano depressurizes, the seismicity will likely decay. But seismicity and deformation go hand in hand. That’s something that’s difficult to admit because deformation researchers and seismic researchers like to compete with each other, all in good fun. But deformation and seismicity are both a consequence of the same thing: When you’re pressurizing the system, you’re inflating [it] and you’re stressing the rock and causing little cracks. As we see the volcano begin to relax and de-stress, we should see a decrease in earthquake activity as well.

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Just a couple of days ago, a water lake filled the bottom of the Halema’uma’u crater. Now, a glowing lava lake does, filling the skies with gases and fog. Credit: USGS.

MS: What are you watching for and excited or interested to see going forward?

MP: My specialty is in volcano deformation, so I naturally gravitate to that. I’m very excited about what we’re going to see deformation-wise because it tells you where the magma is and where it has gone. You can look at these signals and say, “I can see storage areas located in this place or that place. And the eruption came from this storage area, not that one.” Looking back at another time when the summit was very active in the 1960s, we saw evidence of deformation all over the place. But it was difficult to resolve because the tools at the time could only take measurements in a few places, and they weren’t continuous. Well, now we have continuous GPS; we have synoptic views from radar satellites. We will see the summit in a way that hasn’t been possible, with this new technology that’s going to be like turning the light on in a dark room. Suddenly, it’ll all start to come into focus. I’m excited about all the things that are going to be possible and all the things we’re going be able to see. I’m also super interested in the chemistry of the material that’s coming out, because it’s going to tell you something about where it came from and how long it’s been sitting around.

MS: So much for Earth giving us a break, huh?

MP: Yeah, 2020 wasn’t going to let us off the hook that easily.

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Volcanologist Michael Poland, shown here at Yellowstone in 2019, spoke with Temblor Earthquake News about what Kīlauea’s latest rumblings mean for the volcano. Credit: USGS.

See the full article here .


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Stem Education Coalition

Earthquake Alert

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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.

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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
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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