Geology, Earthquakes & Volcanism News and Discussions

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The supervolcano is reportedly inching towards a possible eruption.

https://www.thrillist.com/news/nation/c ... arthquakes

Since it's better to be safe than sorry—especially when the historical track record is not so great—Italy is officially making evacuation plans for the possible future eruption of the Campi Flegrei supervolcano, which is located roughly 12 miles outside of Naples. That the volcano is inching towards a possible eruption (the first one since 1538) isn't a new development. The volcano, the crust of which is reportedly weakening, has been experiencing small earthquakes for a while now, and as Thrillist previously reported, in April alone it counted more than 600 quakes. In the last month, the number of earthquakes spiked to 1,100.

While scientists claim that the eruption is "not at all guaranteed" and while this isn't the first time the volcano has teased a potential outburst, the Italian government announced this week it is choosing to be careful and make evacuation plans. Just in case, lest the Pompeii disaster be repeated! According to officials, the mass evacuation would affect tens of thousands of people living around the volcanic area, Euronews reports. If you include all the nearby towns, the combined population that would be impacted surpasses half a million.

The plan also calls for new precautionary measures, including checking the strength of buildings after all the aforementioned small earthquakes. Per the Italian government, such measures would be discussed at a cabinet meeting. Additionally, Civil Protection Minister Nello Musumeci said that further resources are expected to be directed towards the local civil protection (so that it can better assist in case of an emergency) and to fund an awareness campaign.

However, there's no need to stress for now. On top of the eruption not being certain at all, people living in the area shouldn't worry about being evacuated anytime soon. According to Musumeci, evacuations would only happen in the event of "extreme necessity." If an eruption did happen, people would be immediately evacuated outside of the area via either private or public transport within three days.

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Why We Need To Pay Attention To The San Andreas Fault
by Tom Hale
October 13, 2023

Introduction:

(IFL Science) The San Andreas Fault carves through the Californias at the point where the Pacific Plate stands toe-to-toe with the North American Plate. The boundaries between tectonic plates are often hotbeds of earthquake activity, and this 1,200-kilometer (750-mile) fault line is no different. However, the San Andreas Fault is especially worrying for geologists, not to mention the millions of people who live along its course.

A rupture in the San Andreas Fault was the cause of the 1906 San Francisco earthquake, which killed some 3,000 people and destroyed the vast majority of the city, leaving half the population homeless.

This was certainly not a one-off event. In 1857, a rupture of the San Andreas Fault in central and southern California triggered the Fort Tejon earthquake, which clocked in at around 7.9 magnitude. Just a few people were killed, but it’s often reported as one of the greatest earthquakes ever recorded in the US.

Earthquakes are tricky to predict with certainty. However, by studying historical records and computer modeling, geologists estimate that the San Andreas Fault likely causes significant earthquakes every couple of centuries. It’s not a matter of “if” another earthquake will strike the area, but “when.”

“Based on models taking into account the long-term rate of slip on the San Andreas fault and the amount of offset that occurred on the fault in 1906, the best guess is that 1906-type earthquakes occur at intervals of about 200 years. Because of the time needed to accumulate slip equal to a 20-foot [6-meter] offset, there is only a small chance (about 2 percent) that such an earthquake could occur in the next 30 years,” the United States Geological Survey (USGS) website reads.

Read more here: https://www.iflscience.com/why-we-need ... -71115

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California Supervolcano is Cooling Off but May Still Cause Quakes
October 18, 2023

Introduction:

(Eurekalert) Since the 1980s, researchers have observed significant periods of unrest in a region of California's Eastern Sierra Nevada mountains characterized by swarms of earthquakes as well as the ground inflating and rising by almost half an inch per year during these periods. The activity is concerning because the area, called the Long Valley Caldera, sits atop a massive dormant supervolcano. Seven hundred and sixty thousand years ago, the Long Valley Caldera was formed in a violent eruption that sent 650 cubic kilometers of ash into the air—a volume that could cover the entire Los Angeles area in a layer of sediment 1 kilometer thick.

What is behind the increased activity in the last few decades? Could it be that the area is preparing to erupt again? Or could the uptick in activity actually be a sign that the risk of a massive eruption is decreasing?

To answer these questions, Caltech researchers have created the most detailed underground images to date of the Long Valley Caldera, reaching depths up to 10 kilometers within the Earth's crust. These high-resolution images reveal the structure of the earth beneath the caldera and show that the recent seismic activity is a result of fluids and gases being released as the area cools off and settles down.

The work was conducted in the laboratory of Zhongwen Zhan (PhD '14), professor of geophysics. A paper describing the research appears in the journal Science Advances on October 18.

"We don't think the region is gearing up for another supervolcanic eruption, but the cooling process may release enough gas and liquid to cause earthquakes and small eruptions," says Zhan.

Read more of the Eurekalert article here: https://www.eurekalert.org/news-releases/1005226

For a presentation of the research as pubished in ScienceAdvances: https://www.science.org/doi/10.1126/sciadv.adi9878

[weatheriscool]

Lava studies suggest Earth's core is leaking
By Michael Irving
October 23, 2023

Scientists from Caltech and Woods Hole Oceanographic Institution (WHOI) have found evidence that Earth’s core is leaking. High levels of a particular isotope of helium were found in lava flows in Canada, which the team proposes originated in the planet’s core.

Although we seem content to waste it by blowing it into balloons, helium is relatively rare on Earth. Why? Your first instinct is probably right – it literally floats into the upper atmosphere and usually escapes into space. There are however some reserves of the stuff deep underground, in the Earth’s mantle and core, which is a relic from when the planet was forming from a nebula that also birthed the Sun.

https://newatlas.com/science/earth-core ... lium-lava/

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Bits of Theia Might be in Earth’s Mantle
by David Dickinson
Updated November 2, 2023

Introduction:

(Sky & Telescope) Qian Yuan (Arizona State University) and colleagues have now published the work described below, showing that bits of Theia (the giant impactor that helped create the Moon) survived for billions of years as two huge, dense blobs within Earth's mantle. In the November 2nd Nature, the team published updated work that includes significant additional computer modeling of both the impact itself and the motions within Earth's mantle to make that case.

Yuan points out that, according to the simulations, the collision didn't melt Earth's whole mantle."The lower half of Earth's mantle is mostly solid, and it captures an amount of Theia's mantle (about 2% of Earth's whole mass)," he says, adding that this amount is consistent with the blobs found in the mantle. "Thus, both the ancient planetary evidence and current Earth observation agree with each other that the two blobs likely originated from the impactor Theia."

Researchers out of Arizona State University (ASU) made their case in a great piece of planetary forensics presented at the virtual 52nd Lunar and Planetary Science Conference. Their study posits that the large Theia impactor that struck Earth early on in its history, leading to the Moon's formation, might have left large, dense masses deep in our planet’s mantle today. The study will appear in Geophysical Research Letters.

Read more here: https://skyandtelescope.org/astronomy- ... s-mantle/


An artist's conception of Theia hitting the Earth.
NASA / JPL-Caltech

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Violent Eruptions Still Continuing Off the Coast of Iwoto Island
by Tairiku Kurosawa
November 4, 2023

Introduction:

(Asahi Shimbun) Eruptions from an undersea volcano continued spewing plumes of smoke and ash Nov. 3 around a new islet taking shape off the coast of distant Iwoto island (formerly known as Iwojima) in the Pacific Ocean.

The volcanic activity is occurring in the Ogasawara island chain, some 1,200 kilometers south of Tokyo.

Along with the cooling magma thrown up by the eruptions, pumice started creating a small hill on the emerging islet.

“(The activity) has shifted to one of continuous eruptions,” said Setsuya Nakada, professor emeritus of volcanic geology at the University of Tokyo, who was aboard an Asahi Shimbun plane that flew over the islet on Nov. 3.

“It will likely move to one in which lava starts spewing out,” he said.

Read more here: https://www.asahi.com/ajw/articles/15048458

[raklian]

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Recording the first daily measurements of Earth's rotation shifts
https://phys.org/news/2023-11-daily-ear ... hifts.html
by Technical University Munich

Researchers at the Technical University of Munich (TUM) have succeeded in measuring the Earth's rotation more exactly than ever before. The ring laser at the Geodetic Observatory Wettzell can now be used to capture data at a quality level unsurpassed anywhere in the world. The measurements will be used to determine the Earth's position in space, benefit climate research, and make climate models more reliable.

Care to take a quick step down to the basement and see how fast the Earth has been turning in the last few hours? Now you can at the Geodetic Observatory Wettzell. TUM researchers have improved the ring laser there so that it can provide daily current data, which until now has not been possible at comparable quality levels.

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Iceland Girds for Feared Volcanic Eruption
Mie Olsen
November 14, 2023

Introduction:

COPENHAGEN, Denmark (Courthouse News) — Iceland has been holding its breath since a series of earthquakes hit its southwestern Reykjanes Peninsula last week, leading to fears of seismic activity around the volcanic mountain Thorbjörn.

Iceland’s Meteorological Office has categorized the volcano as showing "heightened unrest with increased likelihood of eruption." On Monday alone, over 900 earthquakes were detected in the active area between the towns of Sundhnúkur and Grindavík.

A 9-mile-long corridor with magma reaching up to 800 meters (2,625 feet) below ground appeared and has caused fear that the movement could lead to a series of dangerous eruptions, which generally happen when the molten or semi-molten rock reaches the surface and explodes as burning lava. However, in Iceland there is also a risk of underwater explosions.

Bill McGuire, a volcanologist and emeritus professor of geophysical and climate hazards at University College London, estimated on Monday that an eruption over the next days is still highly likely.

He said that on land, an eruption would most likely “be dominated by spectacular lava ‘fountaining’ and the production of lava flows,” while “if magma breaks the surface at the southern end of the fracture, it could erupt beneath the sea, which would be a more explosive event.”

Read more here: https://www.courthousenews.com/iceland ... ruption/

[wjfox]

Iceland volcano: Peninsula faces 'decades' of instability

8 hours ago

Iceland's south-western peninsula could face decades of volcanic instability, warns the Icelandic Met Office (IMO).

Earthquakes and fears of an impending eruption have led to the evacuation of the small fishing town of Grindavik.

After an 800-year hiatus, eruptions on the Reykjanes Peninsula began again in 2021, which may mark a new "eruptive cycle", the IMO's Matthew Roberts says.

"We expect to see volcanic eruptions along the peninsula, not just repeatedly in the same location."

This instability, he adds, could last decades.

https://www.bbc.co.uk/news/world-europe-67429872

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[Time_Traveller]

Cornwall shaken by 2.7 magnitude earthquake

1 hour ago

An earthquake has shaken parts of Cornwall, with people saying it felt like an explosion or avalanche.

Seismologists at the British Geological Survey recorded the 2.7 magnitude quake at 00:50 GMT.

Its epicentre was in the Mounts Bay area in south Cornwall, with people woken up by a loud bang from St Just in north Cornwall to Redruth.

Experts said the tremor was within what is expected for the area and is among hundreds in the UK every year.

Linda Dwan, from Mousehole in south Cornwall, said: "There was a rumbling, like thunder and the house shook for about two or three seconds.

https://www.bbc.co.uk/news/articles/c724le759lro.amp

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Indonesia's Mount Merapi Eruption Leaves 11 Climbers Dead and Several Missing
Updated December 3, 2023

Introduction:

(The National) Eleven climbers have been found dead in Indonesia a day after the eruption of Mount Merapi, with rescuers searching for at least 12 others reportedly missing.

The 2,891-metre-high Mount Merapi, on the island of Sumatra, erupted on Sunday, shooting ash plumes as high as 3km and raining debris over nearby villages.

Local and national agency officials raised the number of hikers believed to be on the mountain to 75.

“There are 26 people who have not been evacuated. We have found 14 of them – three were found alive and 11 were found dead,” AFP quoted Abdul Malik, the head of Padang Search and Rescue Agency, as saying a day after the eruption.

A small eruption on Monday led the search being suspended, said Jodi Haryawan, spokesman for the search and rescue team.

Read more here: https://www.thenationalnews.com/world/ ... issing/

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Challenging assumptions: The 8.5-year rhythm of Earth's inner core
https://phys.org/news/2023-12-assumptio ... -core.html
by Tejasri Gururaj , Phys.org

Researchers from China have confirmed the existence of an approximately 8.5-year Inner Core Wobble (ICW) in both polar motion and length-of-day variations, revealing a static tilt of about 0.17 degrees between the Earth's inner core and mantle, challenging traditional assumptions and providing insights into the Earth's internal dynamics and density distribution.

The findings of the study are published in Nature Communications.

The Earth's inner core is a solid, dense sphere composed primarily of iron and nickel. Located beneath the liquid outer core, it spans a radius of about 1,200 kilometers (746 miles). This region plays a crucial role in Earth's geophysical processes, influencing the planet's magnetic field and contributing to the overall dynamics of the Earth's interior.

Understanding the properties and behavior of the inner core is essential for unraveling mysteries related to Earth's structure, seismic activity, and magnetic field.

The ICW refers to the wobbling motion of the Earth's inner core around its rotation axis. This phenomenon is characterized by a periodic oscillation of the inner core's figure axis.

A new study has confirmed that the ICW of Earth has a periodic motion with a cycle lasting approximately 8.5 years. This wobbling motion has been observed in measurements of polar motion, the Earth's rotational axis' periodic movement and length-of-day variations (ΔLOD), and the changes in Earth's rotational speed.

[weatheriscool]

Iceland volcano erupts after weeks of quake activity

Source: Reuters

OSLO, Dec 18 (Reuters) - The Reykjanes volcano in southwest Iceland erupted on Monday, spewing lava and smoke into the air, after weeks of intense earthquake activity, the country's Meteorological Office said.

Fearing a significant outbreak on the Reykjanes peninsula, authorities last month evacuated the nearly 4,000 inhabitants of the fishing town of Grindavik and closed the nearby Blue Lagoon geothermal spa.

Read more: https://www.reuters.com/world/europe/ic ... 023-12-18/

[raklian]

Iceland volcano erupts after weeks of quake activity

Source: Reuters

OSLO, Dec 18 (Reuters) - The Reykjanes volcano in southwest Iceland erupted on Monday, spewing lava and smoke into the air, after weeks of intense earthquake activity, the country's Meteorological Office said.

Fearing a significant outbreak on the Reykjanes peninsula, authorities last month evacuated the nearly 4,000 inhabitants of the fishing town of Grindavik and closed the nearby Blue Lagoon geothermal spa.

Read more: https://www.reuters.com/world/europe/ic ... 023-12-18/