Geology, Earthquakes & Volcanism News and Discussions

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Geologists Have Closely Analyzed Two Bizarre 'Blobs' Detected Deep Inside Earth
by Carly Cassella
March 11, 2022

https://www.sciencealert.com/two-weird- ... -different

Introduction:

(Science Alert) Earth's interior is not a uniform stack of layers. Deep in its thick middle layer lie two colossal blobs of thermo-chemical material.

To this day, scientists still don't know where both of these colossal structures came from or why they have such different heights, but a new set of geodynamic models has landed on a possible answer to the latter mystery.

These hidden reservoirs are located on opposite sides of the world, and judging from the deep propagation of seismic waves, the blob under the African continent is more than twice as high as the one under the Pacific ocean.

After running hundreds of simulations, the authors of the new study think the blob under the African continent is less dense and less stable than its Pacific counterpart, and that's why it's so much taller.

"Our calculations found that the initial volume of the blobs does not affect their height," explains geologist Qian Yuan from Arizona State University.

[erowind]

[wjfox]

Magnitude 7.3 earthquake hits northern Japan, triggering tsunami alerts

23 mins ago

A magnitude 7.3 earthquake was recorded off the coast of Fukushima and Miyagi, Japan, on Wednesday, tripping tsunami alerts in the northeastern regions, according to the country's meteorological agency.

The big picture: The earthquake struck just days after the 11th anniversary of the 9.0 magnitude earthquake and tsunami that devastated Fukushima and triggered a nuclear crisis.

https://www.axios.com/earthquake-japan- ... 9ed5a.html

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This Could Be Why the Massive Volcanic Eruption in Tonga Was So Explosive
by David Nield
March 31, 2022

https://www.sciencealert.com/this-could ... -explosive

Introduction:

(Science Alert) By any measure you want to use, the Hunga Tonga-Hunga Ha'apai volcano eruption in January 2022 was a massive eruption.

It produced a swirling plume of gas, dust and ash that reached 58 kilometers (36 miles) into the sky, atmospheric waves that traveled around the globe several times, and tsunamis in the Caribbean on the other side of the world.

A newly published study now suggests why the scale of this volcanic blast was so huge: a smaller eruption the day before, priming the volcano for a bigger explosion by sinking its main vent under the surface of the ocean.

That meant molten rock was spewing out straight into seawater, vaporizing it along the way and intensifying the eruption. The vaporizing seawater caused the lava to fragment into tiny bits of ash, the researchers suggest.

Combined with ice crystals in the upper atmosphere, the roiling cloud of material built static charges that drove a dramatic period of lightning. The frenzy of electrical activity was so intense, in fact, it represented 80 percent of Earth's lightning strikes in its most active hour.

The research paper is available at this link: https://www.sciencedirect.com/science/a ... 7022000227

[Xyls]

Largest earthquake in history happened in Chile 3,800 years ago, study finds

Yikes... if something like this were to play out today...

https://www.ctvnews.ca/sci-tech/largest ... -1.5867024

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Deep Lake Cores of Ancient Lake Cahuilla Could Help Define Southern San Andreas Fault History
April 22, 2022

https://www.eurekalert.org/news-releases/950625

Introduction:

(EurekAlert) Sediment cores from the ancient Lake Cahuilla at Coachella in southern California could help seismologists determine whether lake filling events are connected to earthquakes on the Southern San Andreas Fault, according to a presentation at the Seismological Society of America’s Annual Meeting.

Lake Cahuilla was a prehistoric lake in California and northern Mexico that covered more than 2000 square miles in the Coachella and Imperial valleys, in the same region as the Southern San Andreas Fault. Today’s Salton Sea occupies part of the original lake footprint.

Sediment layers in two cores, dated with a technique called single-grain luminescence, now extend the lake level history back to about 7000 years, from the previous record of about 2000 years, said Sourav Saha of the Kentucky Geological Survey, University of Kentucky.

Recent paleoseismology studies along the Southern San Andreas Fault suggest that the last seven major ruptures on the fault have occurred at intervals between 116 to 221 years. However, the most recent earthquake in the Lake Cahuilla region occurred about 300 years ago, at the last time the lake was filled. “One of our goals is to see whether there is any relationship between fluctuations in the lake and the activation of the Southern San Andreas Fault,” Saha said.

Some geophysicists think that past fault ruptures might be linked to stages of lake filling, he explained. The increase in pore pressure that could result from lake filling “would most likely reactivate smaller normal faults along the Salton Sea stepover zone, and Coulomb stress models indicate that if you reactivate those extensional faults, it is very likely that you don’t need much to reactivate the Southern San Andreas Fault.”

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What Can Deep Diamonds Tell Us About Deep Earthquakes?
April 22, 2022

https://www.eurekalert.org/news-releases/950624

Introduction:

(EurekAlert) Diamonds that formed deep in the Earth could help seismologists answer a decades-old question: do fluids play a role in generating earthquakes at depths where high pressure should keep brittle failure from happening?

Fluid-assisted faulting in subducted slabs 300 to 700 kilometers deep, in the transition zone between upper and lower mantle, is one process that might explain deep earthquakes. But good evidence for water or other fluids associated with these slabs based on samples was scarce until recently, according to Steven Shirey of the Carnegie Institution for Science.

Now, studies of diamonds that formed in the transition zone provide evidence of fluids carried by subducted slabs. Along with new subduction zone modeling, these diamonds make it clear that fluids can’t be ignored in the story of deep earthquake generation, Shirey said at the Seismological Society of America’s Annual Meeting.

Not all deep earthquakes have to involve water, but modeling by Shirey and his colleagues suggests that some subducting slabs remain cold enough to hold on to and transport water all the way to the bottom of the transition zone. Deep earthquakes, occurring 500 to 700 kilometers below the Earth’s surface, seem to only happen in these slabs that can transport water or that can carry carbonate deep enough to trigger melting, they found.

At that depth, water or carbonate fluids could be triggering the earthquakes, or the earthquakes could be triggering fluid release—or both things could be happening, Shirey said.

[wjfox]

Tonga eruption was 'record atmospheric explosion'

17 minutes ago

The eruption of the Tonga volcano in January has been confirmed as the biggest explosion ever recorded in the atmosphere by modern instrumentation.

It was far bigger than any 20th Century volcanic event, or indeed any atom bomb test conducted after WWII.

The assessment comes in a pair of scholarly papers in the journal Science that have reviewed all the data.

Of recent history, it's likely only the Krakatoa eruption of 1883 rivalled the atmospheric disturbance produced.

That catastrophic event in Indonesia is thought to have claimed more than 30,000 lives. Fortunately, the 15 January climactic eruption of the underwater volcano at Hunga Tonga-Hunga Ha'apai (HTHH) in the south Pacific resulted in very few deaths, even though it too produced large tsunamis.

https://www.bbc.co.uk/news/science-environment-61452860

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While this article (see below) is slightly dated, it was recently cited by Erowind in the chat room, and I do not recall seeing it in this forum before.

Study Confirms that Tonga Volcano Eruption Unlikely to Cool Earth
by Elizabeth Howell
March 01, 2022

(Space.com) The Hunga Tonga volcanic eruption that shook the South Pacific Ocean in January will not affect Earth's climate despite sending clouds of ash dozens of miles high into the atmosphere, a new study confirmed.

Powerful volcanic eruptions, such as the one that ripped apart the uninhabited Polynesian island of Hunga Tonga-Hunga Ha'apai on Jan. 15, sometimes cause short-term cooling of the planet. But this won't be the case of the recent mega-eruption, in spite of the fact that it spewed volcanic ash into record altitudes of more than 25 miles (40 kilometers).

The new study confirms previous estimates, stating that the cooling effect of Hunga Tonga could range from just 0.014 degrees Fahrenheit (0.004 degrees Celsius) in the northern hemisphere and up to 0.018 degrees F (0.01 degrees C) in the southern hemisphere, which is even less than some of the previous estimates expected.

Read more here: https://www.space.com/tonga-volcano-eru ... prediction

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[weatheriscool]

How the world's most active volcano was born

by Silvia Dropulich, Monash University
https://phys.org/news/2022-05-world-volcano-born.html

A new international study led by Monash University has described for the first time what may have triggered the birth of Kilauea, one of the most active volcanoes in Hawaii.

Located along the south eastern shore of Hawaii, Kilauea is estimated to be between 210,000 and 280,000 years old and to have emerged above sea level approximately 100,000 years ago.

In a study published today in Nature Communications lead author Dr. Laura Miller, from the School of Earth, Atmosphere and Environment at Monash University shows for the first time that Hawaiian volcanoes were born from magmas that evolved in an unusually deep (>90 km) magma chamber.

A magma chamber is a large pool of liquid rock beneath the surface of the Earth.

"We obtained some of the very first volcanic products erupted by Kilauea," said Dr. Miller.

"We explored the formation of these samples through experimental work, which involved melting synthetic rocks at high temperatures (> 1100 ˚C) and pressures (> 3 GPa), and by using a new method for modeling their rare earth element concentrations

"We found that the samples could only be formed by the crystallization and removal (fractional crystallization) of garnet."

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Volcano Erupts in Russia's Kamchatka Peninsula
May 28, 2022

Entire article less location map:

(Kyodo News) A large-scale volcanic eruption occurred Saturday in the Russia's far eastern Kamchatka Peninsula, but the Japanese weather agency said no tsunami was observed to have hit Japan.

The Japan Meteorological Agency said that following the eruption at around 5:10 p.m., smoke plumes spewed from Bezymianny and extended over 15 kilometers high.

Since Tuesday, Bezymianny has been experiencing eruptions continuously.

Source: https://english.kyodonews.net/news/2022 ... japan.html

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Antarctica's only active volcano shows how CO2 allows volcanoes to form persistent lava lakes at the surface
https://phys.org/news/2022-05-antarctic ... stent.html
by University of Utah

Antarctica has long been a land of mystery and heroic feats made famous by the explorations of James Ross, Roald Amundsen, Robert Scott and Ernest Shackleton. A key piece of the puzzle for understanding global continental evolution, Antarctica contains examples that define the spectrum of Earth's volcanic processes. Now, a joint University of Utah and University of Canterbury New Zealand study shows how CO2 deep underground helps magma avoid being trapped deep in the Earth and allows it to reach and pool at the surface.

The study, published in Nature Communications "expands our understanding of the sources and transport of diverse types of magma and volatile gases to the surface," says Phil Wannamaker, the study's second author and a geophysicist at the University of Utah's Energy & Geoscience Institute.

"Mount Erebus is an example of a CO2-dominated rift volcano, a complement to the more widely known arc volcanoes of the Pacific Rim and elsewhere, dominated by H2O," adds New Zealand co-investigator Graham Hill, the study's lead author.

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Great timing and supercomputer upgrade lead to successful forecast of volcanic eruption

by University of Illinois at Urbana-Champaign
https://phys.org/news/2022-06-great-sup ... ption.html

In the fall of 2017, geology professor Patricia Gregg and her team had just set up a new volcanic forecasting modeling program on the Blue Waters and iForge supercomputers. Simultaneously, another team was monitoring activity at the Sierra Negra volcano in the Galapagos Islands, Ecuador. One of the scientists on the Ecuador project, Dennis Geist of Colgate University, contacted Gregg, and what happened next was the fortuitous forecast of the June 2018 Sierra Negra eruption five months before it occurred.

Initially developed on an iMac computer, the new modeling approach had already garnered attention for successfully recreating the unexpected eruption of Alaska's Okmok volcano in 2008. Gregg's team, based out of the University of Illinois Urbana-Champaign and the National Center for Supercomputing Applications, wanted to test the model's new high-performance computing upgrade, and Geist's Sierra Negra observations showed signs of an imminent eruption.

"Sierra Negra is a well-behaved volcano," said Gregg, the lead author of a new report of the successful effort. "Meaning that, before eruptions in the past, the volcano has shown all the telltale signs of an eruption that we would expect to see like groundswell, gas release and increased seismic activity. This characteristic made Sierra Negra a great test case for our upgraded model."

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New Evidence Suggests Earth’s Inner Core Oscillates
by David Wells
June 10, 2022

Introduction:

(Courthouse News) — Researchers from the University of Southern California released a study Friday that suggests that the inner core of the Earth oscillates, which could explain the variation in the length of a day.

The findings, published in the journal Science Advances, detail how this new model of Earth’s inner core differs from earlier accepted models.

The previous models suggested that Earth’s inner core rotated, meaning moved in a circle. This new research conducted by seismologist John Vidale of USC Dornsife and researcher Wei Wang suggests that the inner core moves back and forth in oscillation.

“From our findings, we can see the Earth’s surface shifts compared to its inner core, as people have asserted for 20 years,” Vidale said in a statement. “However, our latest observations show that the inner core spun slightly slower from 1969-71 and then moved the other direction from 1971-74. We also note that the length of day grew and shrank as would be predicted.”

The data point to the inner core of earth oscillating instead of rotating.

Read more here: https://www.courthousenews.com/new-evi ... cillates/

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Second, stronger earthquake recorded in two days in Georgia
Source: WGXA Macon

For the second time in two days, an earthquake has been recorded in Georgia.

The second earthquake, recorded at 4:05 a.m. Saturday, was centered in eastern Georgia near the city of Stillmore in Emanuel County.

According to the U.S. Geological Survey, the earthquake had a magnitude of 3.9 and was less than a half-mile under the earth's surface. That shallow depth likely allowed many people in the region to feel light shaking.

Hundreds of people have reported feeling the earthquake through the U.S.G.S. website.

Read more: https://www.msn.com/en-us/news/world/se ... ar-AAYBSfN

[wjfox]

Afghan earthquake: 1,000 people killed and 1,500 wounded, official says

By Frances Mao & Matthew Davis & Leo Sands
BBC News

24 minutes ago

A powerful earthquake has killed one thousand people and left hundreds more injured in Afghanistan, a Taliban official has told the BBC.

Pictures show landslides and ruined mud-built homes in eastern Paktika province, where rescuers have been scrambling to treat the injured.

Taliban leader Hibatullah Akhundzada said hundreds of houses were destroyed and the death toll was likely to rise.

It is the deadliest earthquake to strike Afghanistan in two decades.

The head of information for Paktika province, Mohammad Amin Hazifi, told the BBC that 1,000 people had died and 1,500 are injured.

https://www.bbc.co.uk/news/world-asia-61890804

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^^^IFL Science also had an article on this event. Although largely duplicative of the BBC report, it includes information not included in the BBC article. For example, it features some Twitter feeds on the subject: https://www.iflscience.com/over-1-000-k ... ises-64163

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Seismic waves from earthquakes reveal changes in the Earth's outer core
https://phys.org/news/2022-06-seismic-e ... outer.html
by Suzanne Irby, Virginia Tech

In May 1997, a large earthquake shook the Kermadec Islands region in the South Pacific Ocean. A little over 20 years later, in September 2018, a second big earthquake hit the same location, its waves of seismic energy emanating from the same region.

Though the earthquakes occurred two decades apart, because they occurred in the same region, they'd be expected to send seismic waves through the Earth's layers at the same speed, said Ying Zhou, a geoscientist with the Department of Geosciences in the Virginia Tech College of Science.

But in data recorded at four of more than 150 Global Seismographic Network stations that log seismic vibrations in real time, Zhou found an anomaly among the twin events: During the 2018 earthquake, a set of seismic waves known as SKS waves traveled about one second faster than their counterparts had in 1997.

According to Zhou, whose findings were recently published in Communications Earth & Environment, that one-second discrepancy in SKS wave travel time gives us an important and unprecedented glimpse of what's happening deeper in the Earth's interior, in its outer core.

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While a previous news story cited in this thread mentioned that the Tonga volcano was an extremely powerful atmospheric event, the study reported upon below shows that it was extremely powerful by other methods of measurement as well.

Tonga Volcano Eruption was Among the Most Powerful ever Observed, Triggering Atmospheric Gravity Waves That Reached the Edge of Space
June 30, 2022

Introduction:

(EurekAlert) The eruption of the Hunga Tonga-Hunga Ha’apai submarine volcano in January 2022 was one of the most explosive volcanic events of the modern era, a new study has confirmed.

Led by researchers from the University of Bath and published today in Nature, the study combines extensive satellite data with ground-level observations to show that the eruption was unique in observed science in both its magnitude and speed, and in the range of the fast-moving gravity and atmospheric waves it created.

Following a series of smaller events beginning in December 2021, Hunga Tonga erupted on 15 January this year, producing a vertical plume that extended more than 50km (30 miles) above the surface of the earth. Heat released from water and hot ash in the plume remained the biggest source of gravity waves on earth for the next 12 hours. The eruption also produced ripple-like gravity waves that satellite observations show extended across the Pacific basin.

The eruption also triggered waves in our atmosphere that reverberated around the planet at least six times and reached close to their theoretical maximum speeds – the fastest ever seen within our atmosphere, at 320m per second or 720 miles per hour.

The fact that a single event dominated such a large region is described by the paper’s authors as unique in the observational record, and one that will help scientists improve future atmospheric weather and climate models.

Read more here: https://www.eurekalert.org/news-releases/957419