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earthquakes

Seattle’s landslide risk greater than thought

Landslides have been part of Seattle’s history “from a time to which the memory of man runneth not back,” wrote famed city engineer Reginald Thomson in 1897. A new study shows that landslides will also play a central role long into the future. They will be “extensive and potentially devastating, causing direct losses and impeding recovery,” reported a team in Bulletin of the Seismological Society of America.

17 Mar 2014

Benchmarks: March 27, 1964: The Good Friday Alaska Earthquake and Tsunamis

During the Cold War, many Americans lived in fear of the day their town would be shaken by an atomic bomb blast. On Good Friday 1964, some Alaskans thought that day had come. Beginning at 5:36 p.m., intense ground shaking continued for almost five minutes as the most powerful earthquake ever recorded in North America struck 22.5 kilometers beneath Prince William Sound, where the Pacific Plate is subducting beneath the North American Plate. The shaking — felt over an area of more than 1.3 million square kilometers — was so severe and long-lived that some survivors later said they first thought the Soviet Union had dropped a nuclear bomb on Anchorage, 120 kilometers northwest of the epicenter.

27 Feb 2014

Hazards abroad: Sent home

On May 19, 2012, seismologist Roger Bilham of the University of Colorado at Boulder landed at the airport in Delhi, India, on his way to Bhutan. He debarked from the plane and was met by Indian customs officials, who declared he was on the “blacklist” and not allowed entry to India, despite having a valid visa. Two hours later, he was on a plane heading back to the U.S.

15 Dec 2013

Giant quake sloshed fjords half a world away

On the morning of March 11, 2011, Leif Hus and his wife Gry Melas Hus were having breakfast in their kitchen overlooking Sognefjord in Leikanger, Norway. It was low tide on a calm and windless day with near-freezing temperatures. As they stood, coffee cups in hand, looking out the window at the fjord, they saw an unusual wave roll in. The wave continued to rise, surging over the seawall into their backyard before receding back into the fjord. Then another wave surged in, and another. As the water rose, engulfing the ladder on their dock, Leif grabbed his cell phone and started filming.

02 Dec 2013

Old photos help scientists relocate 1906 San Francisco quake rupture point

Portola Valley, just south of San Francisco, is famous for its progressive approach to geology. The town was the subject of the first geologic map of California and the first municipality in the state to hire its very own resident geologist. There’s a good reason: The section of the San Andreas Fault that produced the deadly San Francisco quake of 1906 runs right through the town. But where exactly the fault trace lies has long been a mystery. Now, in a new study, researchers have used a combination of new technology and old photographs to relocate the fault line.

25 Nov 2013

A public service announcement: Improve geologic literacy starting on the home front

In lieu of doing a "year in review" issue this year, EARTH asked our staff and some frequent contributors to write a short commentary on something that grabbed their attention in 2013. We gave everyone carte blanche. What follows is a collection of extremely varied, often very personal insights into how the planet impacted each individual. In this essay, EARTH's managing editor Megan Sever discusses how she annoys her friends and family with geologic trivia and why you should do the same.

19 Nov 2013

Slab tear explains perplexing Colombian earthquake activity

Colombia sits atop a restless intersection of tectonic plates: The Caribbean Plate is subducting along the country’s northern coast while the oceanic Nazca Plate subducts along its western edge. In between, the narrow but buoyant Isthmus of Panama continues to crash into South America like a battering ram. The complex pattern of earthquake activity produced by these disparate forces has long confounded scientists hoping to decipher the plate structure beneath Colombia.

08 Nov 2013

World's largest deep earthquake recorded

The seismology world may have a new leader in superlatives: On May 24, 2013, the largest, deep earthquake ever recorded struck beneath the Sea of Okhotsk, between the Kamchatka Peninsula and Russian mainland. Scientists are still puzzling over how such a large event could occur so deep.

30 Oct 2013

Scientists demonstrate strengths and shortcomings of method for determining ancient earthquake size

“A giant Cascadia earthquake, with its accompanying tsunami, has the potential to be the biggest natural disaster in this history of the U.S.,” says Simon Engelhart, a seismologist at the University of Rhode Island. On Jan. 26, 1700, a magnitude-9 earthquake associated with the nearby Cascadia Subduction Zone struck the Pacific Northwest.

12 Sep 2013

Alaskan volcano doesn’t just huff and puff, it screams

In March 2009, Alaska’s Mount Redoubt awoke from two decades of silence with something to say: A series of small earthquakes leading up to the eruption produced a seismic sound that staff at the U.S. Geological Survey's Alaska Volcano Observatory nicknamed “the screams.” Now, two new studies are eavesdropping on Redoubt’s inner workings and quantifying the forces needed to produce the unusual harmonic tremors.

16 Jul 2013

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