Volcanoes

volcanoes

Surprise quake at Mount Fuji triggered by rising gases

On March 15, 2011, four days after the magnitude-9 Tohoku megathrust earthquake and tsunami struck Japan, a magnitude-5.9 earthquake shook the southern flank of Mount Fuji. Seismicity has been rare at the volcano since its last eruption in 1707, leading many researchers to suspect that the Fuji quake — which hit about 300 kilometers southwest of the megaquake — was remotely triggered by the Tohoku event. In a new study, scientists looking at the volcano’s underlying structure and plumbing have offered a potential mechanism for how Tohoku’s shaking could have touched off the Fuji earthquake: through rising gas-rich fluids released from the magma chamber beneath the volcano.

27 May 2016

King Oraefajokull

The Öraefajökull Volcano boasts Iceland’s highest peak — 2,109 meters above sea level — and has the reputation of being Iceland’s largest and most violent volcano. Major eruptions in 1362 and 1727 were among the most explosive in the island’s history, and both were accompanied by catastrophic glacial floods. After the 1362 event, the Icelandic word öraefi, originally meaning “area without a harbor,” was rechristened to mean “wasteland.”

29 Mar 2016

Where fire freezes: All eyes, ears and instruments on Iceland's volatile volcanoes

With examples of every type of volcano on Earth — each with its own eruptive pattern — Iceland presents a special challenge to volcanologists, but also serves as an ideal natural laboratory for studying how volcanic processes evolve.

29 Mar 2016

Eerily quiet Katla

Katla Volcano is located near the southern tip of Iceland, under the Mýrdals­jökull Ice Cap. Ashfall deposits found as far away as Norway and Denmark indicate that Katla erupted at least 20 times between A.D. 930 and the last eruption in 1918. Its present dormancy is the longest-known quiet period in the volcano’s history.

29 Mar 2016

Hekla the heckler

Hekla is one of Iceland’s most active volcanoes, erupting more than 25 times since its first recorded eruption in 1104. The most recent eruptions in 1970, 1980, 1981, 1991 and 2000 have allowed geoscientists to create a detailed eruption profile for the volcano.

29 Mar 2016

Impact or eruptions: Are both to blame in the great end-Cretaceous whodunit?

Few episodes in geologic history are as widely recognized — and debated — as the end-Cretaceous extinction. For several decades, the Chicxulub impact has been the primary suspect. But new research suggests the impact wasn’t solely responsible for the extinctions; widespread volcanism in India seemed to play a role as well.

25 Jan 2016

Modeling 'magma mush' could reveal volcanic histories

Volcanic eruptions can spew large amounts of molten rock and ash, putting nearby communities as well as aircraft at risk. Gas emissions and earthquakes sometimes offer clues of when an eruption will occur, but the internal workings of volcanoes are largely unobservable. In a recent study, researchers illuminated these internal processes with a computer simulation that models the flow of the part-liquid, part-solid “magma mush” beneath volcanoes.

18 Dec 2015

Opalescent pools shimmer beneath Santorini

With its bright blue waters and dramatic cliffside villas, Santorini, Greece, is an idyllic vacation destination, but lurking beneath the Aegean waves lay the remains of one of the most active volcanoes in human history. Because of its eruptive past and proximity to population centers, the Santorini Caldera is closely monitored, but a recent expedition revealed something never before seen there or anywhere else: shimmering opalescent pools of carbon dioxide sequestered on the seafloor.
 
15 Nov 2015

Campi Flegrei makes its own concrete caprock

In the 1980s, Tiziana Vanorio was a teenager living in the Italian port city of Pozzuoli west of Naples when the  Campi Flegrei volcanic complex that underlies the town and its harbor began to stir. Between 1982 and 1984, the caldera swelled more than 2 meters — the most rapid volcanic uplift ever measured anywhere. The rising seafloor shallowed Pozzuoli’s harbor so that ships could no longer enter. The uplift was followed by a magnitude-4 earthquake and thousands of microquakes that prompted the evacuation of 40,000 residents. Thereafter, the seismicity waned and the residents returned home, but geologists were left with a puzzle: How did the caldera withstand such extreme strain and deformation for so long without rupturing? 
 
16 Oct 2015

Ancient floods degassed Lake Kivu

The deep, cold waters of Lake Kivu — a stratified volcanic lake in the East African Rift Valley on the border of Rwanda and the Democratic Republic of the Congo — hold 300 cubic kilometers of carbon dioxide gas and 60 cubic kilometers of methane, which seep from magmatic sources below the lake. An overturning of the thermally stratified waters could release those deadly gases onto a population of nearly 2 million.
 
16 Sep 2015

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