Massive Earthquakes Make Volcanoes Sink
volcanos from space

View gallery

The biggest earthquakes also move mountains.

The massive earthquakes that struck Japan and Chile in 2011 and 2010, respectively, sank several big volcanoes by up to 6 inches (15 centimeters), two new studies report.

This is the first time scientists have seen a string of volcanoes drop after an earthquake. Even though the mountains are on opposite sides of the Pacific Ocean, their descents look remarkably similar. The two teams have different explanations for why the volcanoes sank, according to the studies, published today (June 30) in the journal Nature Geoscience. However, both groups agree it's likely scientists will discover more examples of drooping volcanoes after big earthquakes, and find a single mechanism that controls the process.

"It's amazing, the parallels between them," said Matthew Pritchard, a geophysicist at Cornell University in Ithaca, N.Y., and lead author of one of the studies. "I think it makes a really strong case that this is a ubiquitous process."

Into the deep

Researchers as far back as Charles Darwin have noticed that volcanoes sometimes blow their top after earthquakes. And colossal earthquakes, such as the magnitude-9.0 2011 Japan earthquake and the magnitude-8.8 2010 Chile temblor, can trigger small tremors at volcanoes thousands of miles away. But pinning down a direct link between earthquakes and eruptions has eluded scientists. [7 Craziest Ways Japan's Earthquake Affected Earth]

After the Chile and Japan quakes, the research teams behind the two new studies (each group working independently), set out to track signs of coming eruptions. But instead of finding bulging volcanoes — a hint that magma is rising underground — the teams only discovered sagging mountains, or no changes at all. No signs of eruptions appeared in the scores of volcanoes in the two countries.

Instead, volcanoes and massive caldera complexes similar to those at Yellowstone National Park — areas as large as 9 by 18 miles (15 by 30 kilometers) — dropped by 2 to 6 inches (5 to 15 cm). Each area was shaped like a long oval, lined up parallel to the offshore earthquake fault that was located between 200 to 300 km (about 125 to 185 miles ) away. Satellite data revealed the changes to both teams.

"Even without visible eruptions, large earthquakes affect volcanoes," Youichiro Takada, a geophysicist at Kyoto University in Japan and lead author of one of the studies, said in an email interview.

Competing causes

Pritchard and his colleagues, who studied the Chilean earthquake, think the seismic shaking uncorked fissures and fractures that released pent-up hydrothermal fluids at the volcanoes, akin to shaking a soda bottle and then opening the top. As the fluids escaped, the ground settled and sank.

But Takada's group, who studied the Japan quake, thinks magma chambers under the volcanoes sank more than the surrounding region. The hot rock is weaker and deforms more in response to the crustal changes caused by the massive quake.

Their data, which is more precisely timed than the Chile group's thanks to Japan's dense GPS monitoring network, also shows the volcanoes dropped as soon as the earthquake struck.

Further work will tell which model is right, or even if they're both wrong, said Sigurjon Jonsson, a geophysicist at the King Abdullah University of Science and Technology in Saudi Arabia who was not involved in the study.

"The observations in Japan and Chile are so similar that I'm certain that they are caused by the same mechanism (and maybe more than one), instead of two different ones in the two different countries," Jonsson said in an email interview.

Both teams plan to comb through the satellite record for evidence of past sinking after earthquakes of varying sizes, and watch volcanoes during future quakes and catch any changes. 

The studies also offer further evidence of why some earthquakes trigger eruptions and some don't, Pritchard said.

"Basically, the volcanic system has to be primed and ready to go for the earthquake to tip it over the edge," Pritchard said. "If, by chance, no volcanoes are close to that point, no volcanic eruptions are triggered [after an earthquake]," he said.

Email Becky Oskin or follow her @beckyoskin. Follow us @OAPlanet, Facebook & Google+. Original article on LiveScience's OurAmazingPlanet.

Copyright 2013 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.
View Comments (264)

Recommended for You

  • David Cassidy prepares to auction Florida mansion

    FORT LAUDERDALE, Fla. (AP) — Like many of his baby boomer peers with grown children and debts to settle, one-time heartthrob David Cassidy is looking to downsize.

    Associated Press40 mins ago
  • Luggage piece found on French island near possible MH370 debris

    Part of a bag was found Thursday on the French Indian Ocean island of La Reunion not far from plane debris which has fuelled speculation it may be from missing flight MH370. "The piece of luggage was here since yesterday but nobody really paid attention," said Johnny Begue, a member of a local…

  • Family Pet-Sitter Helps Herself To Homeowner's Possessions

    DEAR ABBY: A trusted and beloved family member who takes care of my cats -- and therefore has a key to my house -- has been stealing things like cleaning supplies, knickknacks, family pictures, etc. Most of them have little monetary value. But imagine my surprise when I spotted some of my missing…

    Dear Abby
  • Turkey onslaught on Kurds, after IS attack, fuels anger

    DIYARBAKIR, Turkey (AP) — Just when it seemed Turkey was getting serious about the fight against IS, it has turned its military focus to pounding its old foe: the Kurdish rebels.

    Associated Press5 mins ago
  • An American Dentist Killed Zimbabwe’s Famous Lion

    Cecil the lion, a famous black-maned resident of Zimbabwe’s Hwange National Park, died at the hands of an American dentist, conservationists claim. “Mr. Palmer shot Cecil with a bow and arrow but this shot didn't kill him,” Johnny Rodrigues, chairman of the Zimbabwe Conservation Task Force, said in…
  • Chicago man cleared after 17 years in prison shot dead

    CHICAGO (AP) — A Chicago man who served 17 years in prison for murder before being cleared of the crime has been shot and killed almost three years after being released from prison, police said Wednesday.

    Associated Press
  • Russia reassures Israel over Iran nuclear deal

    Russian President Vladimir Putin told Israeli Prime Minister Benjamin Netanyahu on Thursday that the deal on Iran's nuclear program would improve security in the Middle East and guaranteed that Tehran would not acquire nuclear arms. Israel plans to lobby the U.S. Congress not to approve the…

  • View

    Creeping vines, abandoned village (20 photos)

    Just a handful of people still live in a village on Shengshan Island east of Shanghai that was once home to more than 2,000 fishermen. Every day hundreds of tourists visit Houtouwan, making their way on narrow footpaths past tumbledown houses overtaken by vegetation. The remote village, on one of…

    Yahoo News
  • Colorado theater shooter's dad saw wide-eyed smirk before

    CENTENNIAL, Colo. (AP) — James Holmes came home on winter break from graduate school looking haggard and making odd facial expressions, but his father didn't suspect at the time that he was descending into mental illness.

    Associated Press
  • Dashcam catches off-duty cop threatening to put 'hole in head' of driver

    Technically Incorrect: A Massachusetts driver makes a wrong turn. What happens next, all filmed on his dashcam, has led to an investigation. And yes, it's now on YouTube.

  • Hidden Security Cameras Are Shocking Surprise For Daughter

    DEAR ABBY: I'm a 19-year-old woman in college who still lives with my parents. I found out something several weeks ago that's bothering me, and I need advice badly. Years ago, after a robbery, my parents installed security cameras outside our house. I knew about them because they were visible. But…

    Dear Abby
  • Goat's head nearly severed in brutal knife attack in Idaho

    A small goat was nearly decapitated and another goat died from a "heinous" knife attack on the animals in a fenced and locked site where they had been placed to graze on weeds in northern Idaho, a police spokeswoman said on Wednesday. A third goat is being treated for a knife wound in its back from…

  • Jon Stewart signing off 'Daily Show' fake newscast for real

    NEW YORK (AP) — After more than 16 years and nearly 2,600 telecasts, Jon Stewart can feel proud of his scads of Emmys and his pair of Peabody Awards, his cultural gravitas (he hung with the Prez, both on and off the air!), even his reprobate status at Fox News.

    Associated Press
  • At least '18 dead' in IS attack on Kurd-held Syria town

    At least 18 people were killed Thursday when Islamic State group jihadists attacked a town in northern Syria recently captured by Kurdish forces, a monitor said. The Syrian Observatory for Human Rights monitor said several IS fighters infiltrated Sarrin, in Aleppo province, and attacked a school…

  • China to prosecute former top officer for graft

    China will prosecute a former top military officer for corruption, the government said on Thursday, the second senior officer to be investigated, as President Xi Jinping widens his campaign against deep-rooted graft in the country. Guo Boxiong, 73, was a vice chairman of the powerful Central…

  • Killer deal: Amazon will pay you $10 to buy a $30 Google Chromecast

    Google’s little Chromecast dongle is pretty awesome. The device plugs into the HDMI port on any HDTV or monitor and instantly gives users access to movies, TV shows, videos, music, photos and more that can be streamed from any Android device. Best of all, perhaps, the Chromecast is wonderfully…

    BGR News
  • The Latest: Police: Hate crime not ruled out over MLK flags

    ATLANTA (AP) — The latest on the investigation into Confederate flags found at the Ebenezer Baptist Church near the Martin Luther King Jr. Center in Atlanta:

    Associated Press
  • View

    Photos of the day - July 29, 2015 (20 photos)

    The full moon rises over the illuminated Kazan Kremlin with the Qol Sharif mosque illuminated in Kazan, the capital of Tatarstan, Indian dancers paint their body like tigers as they perform a Tiger dance during the International day of the Tiger in Calcutta and a diver performs with fish as part of…

    Yahoo News