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earthquakes

Inland earthquake triggers distant tsunami

On Sept. 24, 2013, a magnitude-7.7 earthquake struck southern Pakistan, killing more than 800 people. The quake made global headlines in part due to the birth of a small island it triggered just off the coast — a mound of mud dubbed Quake Island that has since washed away. A new study has found evidence of another curious event linked to the quake: a small tsunami that appears to have been remotely triggered by a submarine landslide far from the earthquake’s inland epicenter.

26 Nov 2014

Seismic friction causes fault iridescence

Although iridescent spots on rocks in Utah’s Wasatch Fault Zone were first recognized two decades ago, scientists haven’t understood their origin, until now. New research shows that the iridescence appears on fault surfaces subjected to flash heating from friction and that the spots can provide clues to ancient seismic events. 

11 Nov 2014

Russian earthquake ruptures superfast and deep

A “superfast” magnitude-6.7 earthquake was detected off the coast of Kamchatka, Russia, in May. The earthquake, called a “supershear” quake, is one of a handful of superfast earthquakes noted by researchers over the years, but this is the first identified at such great depth.

24 Oct 2014

We're all living in the global aftershock zone

Can a large earthquake trigger another quake hundreds or even thousands of kilometers away? The answer, scientists say, appears to be yes, but when it happens is far from predictable. How does such dynamic triggering affect global earthquake hazards? Perhaps the whole world should be considered an aftershock zone.

19 Oct 2014

Remote triggering of ice quakes

On Feb. 27, 2010, a magnitude-8.8 earthquake struck the subduction zone off the coast of Chile. The resulting Rayleigh surface waves rippled around the world, triggering small earthquakes in many different tectonic settings, including Antarctica. As the surface waves moved across the white continent, a third of Antarctic seismic stations reported shaking coming from so-called “ice quakes.”

19 Oct 2014

Triggered tremor along the San Andreas Fault

The San Andreas Fault (SAF) in California is one of the most active in the U.S., but the 1,300-kilometer-long strike-slip fault seems to only be susceptible to small-scale dynamic triggering. After the magnitude-9 Tohoku quake in Japan in 2011, the SAF experienced an elevated incidence of tremor up and down its length. The tiny tremors were recorded at depths between 16 and 30 kilometers, below the fault’s seismogenic zone.

19 Oct 2014

Casting a seismic shadow

In the week or two before the magnitude-8.6 Indian Ocean earthquake in 2012, Earth was unusually quiet, with few large quakes over magnitude 5. Afterward, seismic activity all over the globe was elevated for more than a week. Then, suddenly, global seismicity dropped off precipitously: Beginning two weeks after the mainshock, no earthquakes of magnitude-6.5 or greater occurred for 95 days.

19 Oct 2014

Alaskan megathrust fault more active under Kodiak

In 1964, a magnitude-9.2 earthquake ruptured two segments of the Alaskan megathrust fault along more than 900 kilometers from Prince William Sound to Kodiak Island. Historical and paleoseismic evidence has hinted at previous events in this region in 1788 and about 1100, and now a team working on Kodiak Island has found clues of another large event that struck about 500 years ago. The find makes the recurrence interval for the tsunami-producing fault much shorter, potentially increasing the earthquake and tsunami hazard profile, not only for Alaska, but also Hawaii and California.

05 Oct 2014

The Bay Area's next 'big one' could strike as a series of quakes

Californians are bracing for when the San Andreas Fault unleashes the next “big one,” but a new study looking at the paleoseismic history of the San Francisco Bay Area suggests that accumulated stress could also be released in a series of moderate to large quakes on satellite faults, rather than by a single great event on the San Andreas.
 

14 Sep 2014

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