Volcanos / Volcanoes

hunck

Antediluvian
Joined
Jul 13, 2011
Messages
5,507
Reaction score
7,554
Points
284
Location
Hobbs End
Awakening volcanic region in Iceland

Reykjanes peninsula’s last active period started in 10th century and lasted 300 years

Since 21 January, the Reykjanes peninsula south-west of Iceland’s capital, Reykjavik, has experienced more than 8,000 earthquakes and about 10cm of land uplift due to magma intrusions underground.

“It seems that after being relatively inactive for many centuries, this region is waking up,” said Dave McGarvie, a volcanologist at Lancaster University.

the region last erupted about 800 years ago (though there have been more recent eruptions offshore). Geological evidence shows the area is fed by five volcanic systems, which seem to come to life in a coordinated way roughly every 1,000 years.

The last period of volcanic activity on the peninsula began in the 10th century and continued until the 13th. Unlike typical Icelandic volcanoes, which tend to wake for a few years and then die down, when this region gets going it appears to splutter on and off for up to 300 years, producing eruptive episodes (locally known as “fires”) lasting a few decades. Long thin cracks known as fissures extend up to five miles (8km), producing fountains of lava, usually without large amounts of ash or explosive activity.

The most recent “fires” occurred between 1210 and 1240 and covered about 50 sq km of land in lava. At least six separate eruptions occurred, each lasting weeks to months, interspersed with gaps of up to 12 years with no activity.
 

Sharon Hill

Complicated biological machine
Joined
Dec 16, 2014
Messages
724
Reaction score
1,438
Points
139
Location
Pennsylvania, USA
This weekend, lots of people were sharing the old video of Anak Krakatau erupting 2 years ago with the new story that it had a recent ash eruption. End Times comments ensued. But this Iceland story is much more gut-churning. I should try to get there soon for a visit. I may not get the chance in 10 years or so.
 

Tribble

Killjoy Boffin
Joined
Apr 21, 2015
Messages
2,990
Reaction score
6,836
Points
209
Awakening volcanic region in Iceland

Reykjanes peninsula’s last active period started in 10th century and lasted 300 years
If Iceland does pop and, bad case scenario, throws up a load of ash on a regular basis for years (yes I know the article said it didn't last time), that could be a nail in the coffin for much of European air travel.
Ferry and rail companies would do ok, though.
 

EnolaGaia

I knew the job was dangerous when I took it ...
Staff member
Joined
Jul 19, 2004
Messages
19,259
Reaction score
25,963
Points
309
Location
Out of Bounds
'World's largest volcano discovered beneath Pacific
Scientists say that they have discovered the single largest volcano in the world, a dead colossus deep beneath the Pacific waves.
A team writing in the journal Nature Geoscience says the 310,000 sq km (119,000 sq mi) Tamu Massif is comparable in size to Mars' vast Olympus Mons volcano ...
The Tamu Massif was subsequently "disqualified" as the world's largest volcano because it was determined to be a set of multiple volcanos (see earlier post).

This meant Mauna Loa once again held the title. Now a much bigger volcanic structure has been identified and measured in the Pacific.
The World's Largest Shield Volcano Isn't What We Thought It Was

Beneath the cyan and cerulean waters of the Northwestern Hawaiian Islands lurks a leviathan. Its true extent has been hidden for many years, but no more. What geologists have found is a marvel - the biggest, hottest known volcano in the world.

Startlingly, it's more than twice the size of the previous record holder, Mauna Loa on the Island of Hawai'i. ...

The new record-breaker spreads across around 148,000 cubic kilometres (35,507 cubic miles) beneath the waves of the Papahānaumokuākea Marine National Monument, compared to Mauna Loa's 74,000.

Only relatively small rocky pinnacles known as the Gardner Pinnacles break the surface, giving the volcano its name - Pūhāhonu, the Hawai'ian word for 'turtle rising for breath'.

"We are sharing with the science community and the public that we should be calling this volcano by the name the Hawaiians have given to it, rather than the western name for the two rocky small islands that are the only above sea level remnants of this once majestic volcano," said geologist Michael Garcia of the University of Hawai'i at Manoa.

Back in the 1970s, low-resolution bathymetric data suggested Pūhāhonu was around 54,000 cubic kilometres in size, then thought to be the largest volcano before a more extensive survey of Mauna Loa revealed its true size.

Pūhāhonu only regains its crown after extensive surveys of the region added high-resolution bathymetric and multibeam sonar data to our existing understanding of the northwest Hawaiian Ridge, from which the volcano rises. ...
FULL STORY: https://www.sciencealert.com/the-world-s-largest-volcano-isn-t-what-we-thought-it-was
 

EnolaGaia

I knew the job was dangerous when I took it ...
Staff member
Joined
Jul 19, 2004
Messages
19,259
Reaction score
25,963
Points
309
Location
Out of Bounds
New research suggests active volcanism may still be occurring in northern Europe.
Volcanism Under the Heart of Northern Europe: New Evidence From Thousands of GPS Antennas

Scientists have discovered new evidence for active volcanism next door to some of the most densely populated areas of Europe. The study ‘crowd-sourced’ GPS monitoring data from antennae across western Europe to track subtle movements in the Earth’s surface, thought to be caused by a rising subsurface mantle plume. The work is published in Geophysical Journal International.

The Eifel region lies roughly between the cities of Aachen, Trier, and Koblenz, in west-central Germany. It is home to many ancient volcanic features, including the circular lakes known as ‘maars’.

These are the remnants of violent volcanic eruptions, such as the one which created Laacher See, the largest lake in the area. The explosion that created this is thought to have occurred around 13,000 years ago, with a similar explosive power to the cataclysmic Mount Pinatubo eruption in 1991.

The mantle plume that likely fed this ancient activity is thought to still be present, extending up to 400km down into the Earth. However, whether or not it is still active is unknown: “Most scientists had assumed that volcanic activity in the Eifel was a thing of the past,” said Prof. Corné Kreemer, lead author of the new study. “But connecting the dots, it seems clear that something is brewing underneath the heart of northwest Europe.” ...

The new results complement those of a previous study in Geophysical Journal International that found seismic evidence of magma moving underneath the Laacher See. Both studies point towards the Eifel being an active volcanic system.

The implication of this study is that there may not only be an increased volcanic risk, but also a long-term seismic risk in this part of Europe. ...
FULL STORY: https://scitechdaily.com/volcanism-...-new-evidence-from-thousands-of-gps-antennas/
 

hunck

Antediluvian
Joined
Jul 13, 2011
Messages
5,507
Reaction score
7,554
Points
284
Location
Hobbs End
Ancient Tree Rings Could Pin Down Date of Massive Thera Volcano Eruption

By comparing tree rings from around the world, a tentative date of 1560 B.C. arrived at.

Since the inception of the UArizona Laboratory of Tree-Ring Research in 1937, an assortment of tree ring samples from all over the world accumulated in less-than-ideal conditions beneath Arizona Stadium. But since the completion of the university’s upgraded Bryant Bannister Tree Ring Building in 2013, the curation team, led by Peter Brewer, has been relocating, organizing and preserving samples for future research.

“This is the collection that founded the field of tree ring research, and it’s by far the world’s largest,” Brewer said. “Researchers come from all over to use our collection.”

“It’s just crammed full of the remains of ancient forests and archaeological sites, which no longer exist, and it contains wood samples that were fundamental in the growth of the discipline of dendrochronology,” Pearson said.

Pearson, a University of Arizona assistant professor of dendrochronology and anthropology, is lead author of a paper, published in the Proceedings of the National Academy of Sciences, in which she and her colleagues have used a new hybrid approach to assign calendar dates to a sequence of tree rings, which spans the period during which Thera erupted, to within one year of a calendar date. This allows them to present new evidence that could support an eruption date around 1560 B.C.
Full details at link.
 
Top