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Eight Seconds of Terror

By Guest PostJanuary 17, 2014Environmentandrea donnellan, aperture radar mission, better models, blind thrust fault, california, crack, crust, crustal deformation, data analyses, downtown los angeles, earth, earthquake faults, earthquake in long beach, eight seconds, geodetic imaging techniques, geophysicist, global positioning system, golden guardian, gps, isro, large earthquakes, NASA, nature magazine, northridge earthquake, periodic shakeout, plate boundary observatory, reseda, rupture, san fernando valley, synthetic, terror, uavsar

A JPL Scientist Reflects on L.A.’s Last Big Quake

Twenty years ago this week, in the predawn darkness of Jan. 17, 1994, at five seconds before 4:31 a.m. PST, the ground ruptured violently on a blind thrust fault (a crack in Earth’s crust that does not reach the surface) about 11 miles (18 kilometers) beneath Reseda, in California’s San Fernando Valley about 20 miles (31 kilometers) northwest of downtown Los Angeles. The resulting magnitude 6.7 earthquake, known as the Northridge earthquake, became the first large quake to strike directly under an urban area in the United States since the 1933 magnitude 6.4 earthquake in Long Beach, Calif. (more…)

Scientists Study Earthquake Triggers in Pacific Ocean

By Guest PostJuly 2, 2011Environmentaccretionary margins, alaska to patagonia, basalt rock, costa rica, costa rica seismogenesis project, crisp, earthquake generating region, earthquakes, eastern pacific ocean, expedition, fault, global earthquakes, integrated ocean drilling program, iodp, italy, Japan, joides resolution, kohtaro ujiie, kristin hillis, large earthquakes, marianas, masaoki uno, mass transfer, michael stipp, nankai trough seismogenic zone experiment, nantroseize, national science foundation, nsf, pacific northwest, paola vannucchi, plate boundary, rodey batiza, samples of rock and sediment, scientific drilling vessel, seafloor, seismic plate boundary, seismogenic region, subduction processes, subduction zones, subseafloor, sumatra quakes, tectonic activity, the aleutians, tohoku earthquake, understanding of the earth, university of florence, university of tsukuba

*Samples of rock, sediment from beneath the sea-floor help explain quakes like Japan’s*

New samples of rock and sediment from the depths of the eastern Pacific Ocean may help explain the cause of large, destructive earthquakes similar to the Tohoku Earthquake that struck Japan in mid-March.

Nearly 1,500 meters (almost one mile) of sediment cores collected from the ocean floor off the coast of Costa Rica reveal detailed records of some two million years of tectonic activity along a seismic plate boundary. (more…)

No Evidence for Large Triggered Earthquakes Across the Globe

By Guest PostMarch 29, 2011Environmentdamaging earthquakes, global seismic hazard, large earthquakes, m5, m7, nature geosciences, seismic wave, tom parsons

MENLO PARK, Calif. — New scientific research concludes that large earthquakes do not increase the global seismic hazard for more damaging earthquakes far from the mainshock. Although large aftershocks close to the mainshock remain highly probable following an earthquake, and small earthquakes less than magnitude 5 can be triggered at great distances, scientists at the U.S. Geological Survey and the University of Texas at El Paso found no significant increase in the rate of large earthquakes happening farther away than two to three times the length of the ruptured fault that caused the mainshock. (more…)

Tag Archives: large earthquakes

Eight Seconds of Terror

Scientists Study Earthquake Triggers in Pacific Ocean

No Evidence for Large Triggered Earthquakes Across the Globe