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Saturday, 25 May 2013

Earth events - 24 May

Shallow 5.7 magnitude northern California earthquake felt across two states


24 May, 2013

An earthquake in far northeastern California did not injure anyone but did cause moderate damage, including to a water tank that supplies hundreds of homes with drinking water, local authorities said Friday.

Plumas County Sheriff Greg Hagwood said the magnitude-5.7 quake sent items tumbling from grocery store shelves and downed chimneys when it hit at 8:47 p.m. Thursday.

The U.S. Geological Survey's National Earthquake Center said the temblor was centered near Greenville, about 25 miles southwest of Susanville, and was felt as far away as San Francisco and in two other states. It was followed by multiple aftershocks, including a magnitude 4.9 quake that struck early Friday morning.

About 300 people were affected by the damaged water system, Hagwood said.

"Without question, it's the strongest quake I've ever felt here. It was very unsettling and it lasted long enough to create a measure of anxiety," Hagwood said. "The supermarkets and stores had a lot of things come off the shelves."

Pacific Gas & Electric said about 660 customers lost power on the southwestern edge of Lake Almanor at about 9:39 p.m. Thursday.

Susan Shephard and her husband Alan Shephard, who run the Quail Lodge at Lake Almanor near Greenville very close to the epicenter, said they were watching "The Hunger Games" on TV when the whole building started shaking.

"All of a sudden things started falling off the shelves, mirrors fell off the wall, vases fell down to the floor, everything started crashing," Shephard told the Redding Record-Searchlight. "It felt like the end of our world."

The Susanville Fire Department said it had received no reports of damage, and a Plumas County Sheriff's Office dispatcher said calls were flooding into its office but no reports of damage.

Thousands of people reported feeling the quake, as far away as the San Francisco Bay area and across the borders into Oregon and Nevada, according to the USGS website.

KCRA-TV in Sacramento reported that the Plumas County temblor was felt in downtown Sacramento, about 145 miles south of the epicenter.

People in Yuba and Sutter Counties, south of Plumas, said they felt a rolling quake, according to the Marysville Appeal-Democrat.

"People in the area felt a strong jolt, but it was not enough to generate serious damage, based on early field reports," said Rafael Abreu, a geophysicist with the U.S. Geological Survey's National Earthquake Center in Golden, Colo.


Deep 8.3 magnitude earthquake strikes Sea of Okhotsk in Russia’s Far East
A magnitude 8.2 earthquake struck off Russia's eastern coast on Friday, briefly prompting a tsunami scare but causing no casualties or substantial damage, Russian emergency authorities said.


24 May, 2013

The epicentre of the quake was located at a depth of 385 miles in the Sea of Okhotsk, 244 miles west of the nearest city, Petropavlovsk-Kamchatsky, the U.S. Geological Survey said.

The quake was felt in Petropavlovsk-Kamchatsky, the main city on the Kamchatka peninsula and home to a nuclear submarine base, and on Sakhalin island, where Russia's largest liquefied natural gas project is located.

Regional emergency authorities issued a tsunami warning for Sakhalin and the Kurile islands, advising residents of dangerous areas to seek high ground, but lifted the warning several minutes later.

Residents of northern Japan felt the quake but there was no tsunami warning from Japan's meteorological agency.

Pacific Plate turbulence increases

At 103 million square kilometers, the Pacific plate is the largest of the tectonic plates and consequently the most violent. Geological forces are tearing at the integrity and stability of this large lithospheric cross-section of the planet. As I reported several days ago, seismic tension was mounting along the Pacific tectonic plate. The cascading series of earthquakes over the last 24 hours are yet one more indication that dynamic geological change is accelerating within the interior of the planet. These processes of change will have profound implications for the entire Ring of Fire and all subduction zones located within this region.


Chirinkotan Volcano erupts in Kuril Islands of Far East Russia


The remote volcano in the northern Kuriles is probably in eruption, the latest SVERT report and satellite images suggest. A plume of gas and steam, and possibly some minor amounts ash was seen with the MODIS sensor onboard the NASA Terra satellite this morning.

Satellite data also indicate that activity had likely already started in early May, because a small thermal anomaly can be traced back on archive pictures to 7 May. One should take into account that frequent dense cloud cover often prevents such observations, so activity could have started earlier than that.

It is not known what kind of activity is occurring at the volcano. Possibilities include some minor explosive (strombolian ?) activity at the summit, or lava flows that might be reaching the sea and produce the steam plume observed.

The last eruption of the volcano was (probably) in 2004.




Eruption continues in Mexico




Mexico’s Popocatepetl volcano unleashed another wave of powerful exhalations and explosions in the early hours of Thursday (May 23), officials reported. Hundreds of individual exhalations reaching up to 2.5 km (1.5 miles) of smoke and ash spewed out of Popocatepetl in the latest escalation in activity. An explosion at 02:54 local time (06:54 GMT) also sent fragments out over 1.5 kilometers (0.9 miles), Mexico’s National Centre for Disaster Prevention reported. -WSBRADIO



Alert level raised on Chile’s Copahue volcano to orange after ash emissions


SERNAGEOMIN has raised the alert level to orange. Since May 15, a progressive increase in seismic activity as well emissions of gas and now some ash have been observed.

Both earthquakes related to rock fracturing and fluid movements have picked up in numbers and possibly indicate a new magmatic intrusion on its way.

This scenario is confirmed by the start of small ash emissions and glow at the crater which is visible at night. The plume of gas and ash could be seen from space by the MODIS sensor, streching about 100 km to the southeast.

Copahue volcano had already experienced a first increase of activity in December, and a second one in January. No eruption followed and alert was lowered to green in April before returning to yellow again soon after.

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