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Posts Tagged ‘earthquake’

6.4 quake shakes northern Argentina, capital

September 2, 2011 Comments off

 

BUENOS AIRES, Argentina—A magnitude-6.4 earthquake has struck north-central Argentina, shaking things up enough to make people evacuate some buildings in the capital hundreds of miles (kilometers) away.

The U.S. Geological Service says the quake’s epicenter was 80 miles (130 kilometers) southeast of Santiago del Estero, a provincial capital of 250,000 people and the 12th-largest city in Argentina.

It was centered deep underground, nearly 400 miles (600 kilometers) below the surface, where quakes generally cause less damage.

The shaking prompted people to spill out of the San Isidro courts building in Buenos Aires province Friday morning.

7.1 Quake strikes off Alaskan coast

September 2, 2011 Comments off

cnn.com

An earthquake with a preliminary magnitude of 7.1 struck Friday off the coast of Alaska, the U.S. Geological Survey reported.

The quake was initially reported to have occurred a depth of 6.2 miles, but the Geological Survey later updated its reading to say it was 22 miles deep.

The earthquake occurred 120 miles east-southeast of Atka, Alaska, in a sparsely populated part of the Aleutian Islands known as the Fox Islands. The epicenter was 1,658 miles west southwest of Anchorage, the Geological Survey said.

It prompted a brief tsunami Read more…

4.2-magnitude quake rumbles across Los Angeles

September 1, 2011 Comments off

ap

LOS ANGELES (AP) — A magnitude-4.2 earthquake and aftershocks rattled nerves across the Los Angeles region Thursday, but there were no immediate reports of damage.

The quake hit around 1:47 p.m. and was centered 24 miles northwest of downtown Los Angeles. It was followed by more than a half-dozen aftershocks up to magnitude-3. The jolt was felt widely across Los Angeles County including the San Fernando and Read more…

Strong 6.8 quake hits near East Timor

August 30, 2011 Comments off

afp

DILI, East Timor — A powerful 6.8-magnitude earthquake struck deep beneath the seabed near East Timor on Tuesday but no tsunami warning was issued, a local geophysics agency said.

The quake hit at 13:57 pm (0657 GMT) at a depth of 469 kilometres (291 miles), about 271 kilometres northeast of the capital, Dili, according to Indonesia’s geophysics agency.

“We did not issue a tsunami warning. There are no reports of damage so far,” said Novita, an official at Indonesia’s national quake centre.

“The quake was felt by the people in Timor island, but not strongly,” Read more…

Virginia quake may have exceeded nuclear plant design

August 30, 2011 Comments off

reuters

The historic earthquake that shut Dominion Resources Inc’s North Anna nuclear plant in Virginia last week may have shaken the facility more than it was designed to withstand, the U.S. nuclear regulator said on Monday.

The Nuclear Regulatory Commission said it had sent a special inspection team to the plant rocked by the 5.8-magnitude quake, after initial reviews from Dominion indicated the ground motion may have exceeded North Anna’s design parameters.

The plant cannot be restarted until the operator can show no Read more…

Papua New Guinea rattled by 6.8 quake

August 1, 2011 Comments off

afp

SYDNEY — The Pacific island nation of Papua New Guinea was jolted by a powerful 6.8-magnitude earthquake Monday, prompting a minor tsunami warning, but there were no immediate reports of damage or injuries.

The US Geological Survey said the quake occurred at a depth of 16 kilometres (10 miles), some 131 km (81 miles) east of Wewak and 706 kilometres north of the capital Port Moresby.

“No destructive widespread tsunami threat exists based on historical earthquake and tsunami data,” the Pacific Tsunami Warning Centre said.

“However, earthquakes of this size sometimes generate local tsunamis that can be destructive along coasts located within a hundred kilometers of the earthquake epicentre.

“Authorities in the region of the epicentre should be aware of this possibility and take appropriate action.”

GeoScience Australia measured the quake at 6.6 and said it would have been felt more than 800 kilometres (496 miles) away, but damage would only have been caused within a radius of 67 kilometres from the epicentre.

The PNG Geophysical Observatory said that residents of the coastal town of Wewak, home to about 18,000 people, would have been severely shaken, but early reports suggested no major damage or injuries.

“Preliminary reports we are receving indicate that no real life-threatening damage and it is not an event where a tsunami is thought to be Read more…

New Force Driving Earth’s Tectonic Plates: ‘Hot Spots’ Of Plume From Deep Earth Could Propel Plate Motions Around Globe Discover Scripps Researchers

July 7, 2011 1 comment

nanopatentsandinnovations

Bringing fresh insight into long-standing debates about how powerful geological forces shape the planet, from earthquake ruptures to mountain formations, scientists at Scripps Institution of Oceanography at UC San Diego have identified a new mechanism driving Earth’s massive tectonic plates.

Reconstruction of the Indo-Atlantic Ocean 63 million years ago, during the time of the superfast motion of India which Scripps scientists attribute to the force of the Reunion plume head. The arrows show the relative convergence rate of Africa (black arrows) and India (dark blue) relative to Eurasia before, during and after (from left to right) the period of maximum plume head force. The jagged red and brown lines northeast of India show two possible positions of the trench (the subduction zone) between India and Eurasia depending on whether the India-Eurasia collision occurred 52 million years ago or 43 million years ago.

Reconstruction of the Indo-Atlantic Ocean 63 million years ago, during the time of the superfast motion of India which Scripps scientists attribute to the force of the Reunion plume head.  The arrows show the relative convergence rate of Africa (black arrows) and India (dark blue) relative to Eurasia before, during and after (from left to right) the period of maximum plume head force. The jagged red and brown lines northeast of India show two possible positions of the trench (the subduction zone) between India and Eurasia depending on whether the India-Eurasia collision occurred 52 million years ago or 43 million years ago.

Credit: Scripps Institution of Oceanography

Scientists who study tectonic motions have known for decades that the ongoing “pull” and “push” movements of the plates are responsible for sculpting continental features around the planet. Volcanoes, for example, are generally located at areas where plates are moving apart or coming together. Scripps scientists Steve Cande and Dave Stegman have now discovered a new force that drives plate tectonics: Plumes of hot magma pushing up from Earth’s deep interior. Their research is published in the July 7 issue of the journal Nature.

Using analytical methods to track plate motions through Earth’s history, Cande and Stegman’s research provides Read more…