Geology, Earthquakes & Volcanism News and Discussions

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Radar satellite data reveals 19,000 previously unknown undersea volcanoes
https://phys.org/news/2023-04-radar-sat ... known.html
by Bob Yirka , Phys.org
A team of oceanographers at the Scripps Institution of Oceanography, working with a colleague from Chungnam National University and another from the University of Hawaii, has mapped 19,000 previously unknown undersea volcanoes in the world's oceans using radar satellite data. In their paper published in the journal Earth and Space Science, the group describes how they used radar satellite data to measure seawater mounding to find and map undersea volcanoes and explains why it is important that it be done.

The ocean floor, like dry land masses, features a wide variety of terrain. And as with dry land, features that truly stand out are mountains—in the ocean they are called seamounts. And as on land, they can be created by tectonic plates pushing against one another, or by volcanos erupting. Currently, just one-fourth of the sea floor has been mapped, which means that no one knows how many seamounts exist, or where they might be. This can be a problem for submarines—twice U.S. submarines have collided with seamounts, putting such vehicles and their crew at risk. But not knowing where the seamounts are located presents another problem. It prevents oceanographers from creating models depicting the flow of oceanwater around the world.

In this new effort, the research team set themselves the task of discovering and mapping as many seamounts as possible, and to do it, they used data from radar satellites. Such satellites cannot actually see the seamounts, of course, instead they measure the altitude of the sea surface, which changes due to changes in gravitational pull related to seafloor topography; an effect known as sea mounding. In so doing, they found 19,000 previously unknown seamounts.
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Magnitude 7.3 earthquake hits Indonesia, triggers tsunami warning
REUTERS
PUBLISHED 2 HOURS AGO
UPDATED 1 HOUR AGO

https://www.theglobeandmail.com/world/a ... i-warning/

"SNIP........

A magnitude 7.3 earthquake struck west of Indonesia’s Sumatra Island on Tuesday, Indonesia’s geophysics agency (BMKG) said, triggering a tsunami warning.

The European-Mediterranean Seismological Centre (EMSC) earlier pegged the quake at 6.9 magnitude.

The quake, at 84 kilometre (52.2 miles) depth, triggered an initial tsunami warning, the country’s meteorological department added. The agency asked local authorities to immediately instruct residents of the affected area to stay away from shores.

Indonesia’s disaster mitigation agency said authorities are collecting data from the islands nearest the epicentre, off the western shore of Sumatra, spokesperson Abdul Muhari said.
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This article is slightly dated, but better late than never. (Especially since there have been no posts in this thread dated later than May 25, 2023).

Volcano Rumbles Near Mexico City, Coating Towns With Ash, Disrupting Flights
by Megan Janetsky
May 25, 2023

Introduction:
MEXICO CITY (AP) — Towering a couple of hours from one of the world’s largest cities, the Popocatepetl volcano has been coating nearby towns with ash and disrupting flights at Mexico City’s airport, the busiest in Latin America.

Hundreds of explosions have spit lava from the snow-tipped peak of the 17,797-foot Popocatepetl (puh-puh-ka-TEH-pet-tl). Approximately 25 million people live within 60 miles of the mountain. Volcanologists say that, while a massive eruption doesn’t appear imminent, eruptions are likely to continue, as they have for three decades.

What Is Happening With the Popocatepetl Volcano?

There has been a surge of activity since 1994 at the volcano affectionately known as “Popo,” which is being tracked by scientists at Mexico’s National Autonomous University (UNAM).

It has had periods of intense activity between 2000 and 2003, and again between 2012 and 2016. In 2000, that activity triggered a red alert and evacuations before the volcano calmed down again.

In the past weeks, the volcano entered another one of those periods. Spewing ash, gas and lava, authorities have increased the alert to yellow, the second level on a stoplight-style scale, but not yet to red.

Read more here: https://www.latinorebels.com/2023/05/2 ... yvolcano/
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Campi Flegrei volcano edges closer to possible eruption

by University College London
https://phys.org/news/2023-06-campi-fle ... loser.html
The Campi Flegrei volcano in southern Italy has become weaker and more prone to rupturing, making an eruption more likely, according to a new study by researchers at UCL (University College London) and Italy's National Research Institute for Geophysics and Volcanology (INGV).

The volcano, which last erupted in 1538, has been restless for more than 70 years, with two-year spikes of unrest in the 1950s, 1970s and 1980s, and a slower phase of unrest over the last decade. Tens of thousands of small earthquakes have occurred during these periods and the coastal town of Pozzuoli has been lifted by nearly 4 m (13 ft), roughly the height of a double-decker bus.

The new study, published in the journal Communications Earth & Environment, used a model of volcano fracturing, developed at UCL, to interpret the patterns of earthquakes and ground uplift, and concluded that parts of the volcano had been stretched nearly to breaking point.

Lead author Professor Christopher Kilburn (UCL Earth Sciences) said, "Our new study confirms that Campi Flegrei is moving closer to rupture. However, this does not mean an eruption is guaranteed. The rupture may open a crack through the crust, but the magma still needs to be pushing up at the right location for an eruption to occur."
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Tonga Volcano Eruption Created Highest Lightning Rates Ever Recorded On Earth

https://www.forbes.com/sites/davidbress ... 6047ff2c6f



https://universeodon.com/@JenLucPiquant ... 7890722225
New research shows that the plume emitted by the Hunga Tonga-Hunga Ha'apai volcano eruption on January 15, 2022, created the highest lightning flash rates ever recorded on Earth, more than any storm ever documented.

"The eruption of Hunga Volcano was the largest volcanic explosion since Krakatau in 1883," said atmospheric physicist Sonja Behnke, of Los Alamos National Laboratory's Electromagnetic Sciences and Cognitive Space Applications group and author on the paper. It was a phreatoplinian eruption, which occurs when a large volume of magma erupts through water. Previously, this eruption style was only known from the geological record and had never been observed with modern instrumentation according to a news statement by the American Geophysical Union.

Powerful volcanic eruptions produce ash plumes that can create huge amounts of static electricity, produced by movements and collisions between ash particles, and even their own weather systems, providing the conditions for lightning at higher altitudes than normally seen. When the undersea volcano in Tonga erupted, it created a plume that went more than 25 miles higher than typical thunderstorms. Lightning was observed at stratospheric altitudes (12 to 18 miles), where the air pressure is too low to support thunderstorm-like lightning. This fast-rising volcanic plume may have created locally higher pressures to support the environment necessary for lightning.

After reaching its maximum height, the plume expanded outward as an umbrella cloud, creating fast-moving circular ripples known as gravity waves, similar to a rock dropped in a pond. Donut-shaped rings of lightning expanded with the umbrella cloud and were as large as 174 miles in diameter. Similar "lightning holes" have been observed in thunderstorms, but never on this large of a scale.
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Lasering Lava to Forecast Volcanic Eruptions
July 5, 2023

Introduction:
(Eurekalert) University of Queensland researchers have optimised a new technique to help forecast how volcanoes will behave, which could save lives and property around the world.

Dr Teresa Ubide from UQ’s School of the Environment and a team of international collaborators have trialled a new application of the tongue-twisting approach: laser ablation inductively coupled plasma quadruple mass spectrometry.

“It’s a mouthful, but this high-resolution technique offers clearer data on what’s chemically occurring within a volcano’s magma, which is fundamental to forecasting eruption patterns and changes,” Dr Ubide said.
Conclusion:
The team is now trialling a similar technique on volcanic ash, which can be sampled more readily during a volcanic event.

“We are excited to collaborate with volcano observatories to implement the method as a monitoring tool,” Dr Ubide said.
Read more here: https://www.eurekalert.org/news-releases/994385
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