Earthquakes
A tsunami alert originally was issued for several countries in the region including Indonesia and Japan and for Pacific islands as far away as the Northern Marianas, but they all were later lifted, the Pacific Tsunami Warning Center said.
The center said that very small tsunami waves of 3 centimeters meters (just over an inch) were recorded along the eastern Philippine coast near Legazpi city and another nearby location.
Benito Ramos, a retired general who heads the country's disaster-response agency, said in an advisory broadcast nationwide that residents should be on the alert for aftershocks.
2012-08-31 12:47:34 UTC
2012-08-31 20:47:34 UTC+08:00 at epicenter
2012-08-31 05:47:34 UTC-07:00 system time
Nearby Cities
96km (60mi) E of Sulangan, Philippines
109km (68mi) ESE of Guiuan, Philippines
162km (101mi) ESE of Borongan, Philippines
176km (109mi) NE of Surigao, Philippines
747km (464mi) ESE of Manila, Philippines
The nearly 4,000-foot-high Little Sitkin volcano is named for the island where it resides, located in the Rat Islands in the Aleutian chain. The volcano has shown little activity since scientists have started observing it, with only three questionable eruptive events at the volcano since that time.
The most recent eruption may have come in 1900, according to the Alaska Volcano Observatory.
Still, the AVO page for Little Sitkin mentions there may have been a "cataclysmic eruption" on the island sometime after the last ice age, which ended more than 11,000 years ago.
Seismic equipment located near the volcano began detecting a "swarm of high-frequency earthquakes" at about 7:15 p.m. Wednesday, the AVO reports. The earthquakes continued through the night into Thursday, prompting the alert level at the volcano being raised. The alert level is currently at yellow, which means that the "volcano is exhibiting signs of elevated unrest above known background level." Additionally, aircraft traveling in the area are advised to exercise caution.
The volcano is located in a remote part of the Aleutians, about 35 miles northwest of the World War II outpost of Amchitka and 200 miles west of Adak.
Little Sitkin joins two other Alaska volcanoes, Iliamna and Cleveland, currently sitting at elevated alert levels.
Scientist in charge John Power says there is no direct link to the swarm of earthquakes at Little Sitkin and a cluster of quakes that shook California's Imperial County this week.
Powers says Little Sitkin is on an uninhabited island and is far from any populated areas. He says the seismic activity is unusual for Little Sitkin, which may have last erupted in the early 1900s.
Powers says the concern about an eruption would be the possible threat posed to aircraft by airborne ash.
2012-08-30 13:43:24 UTC
2012-08-30 12:43:24 UTC-01:00 at epicenter
2012-08-30 06:43:24 UTC-07:00 system time
Nearby Cities
93km (58mi) NW of Olonkinbyen, Svalbard and Jan Mayen
709km (441mi) NNE of Akureyri, Iceland
939km (583mi) NNE of Reykjavik, Iceland
942km (585mi) NNE of Kopavogur, Iceland
947km (588mi) NNE of Hafnarfjordur, Iceland
Seismologist Garry Rogers from the Pacific Geoscience Centre said the quake hit at 3:20 p.m. and was concentrated about 10 kilometres northwest of Colwood, toward Sooke Lake.
The earthquake came from about 25 kilometres underground.
"It was felt pretty much throughout the area," Rogers said. "We got reports from Sidney to Sooke to all over Greater Victoria." A 3.0-magnitude earthquake, described as minor by local experts, caused some shaking in Greater Victoria but no recorded damage Wednesday afternoon.
Source: The Victoria Times Colonist
There was scattered damage around Brawley, but officials have not yet compiled a full estimate of the costs. The Brawley City Council on Tuesday declared a local emergency, according to the Imperial Valley Press.
Hundreds of earthquakes have rattled Imperial County since Sunday morning as an earthquake swarm continued.
But experts say the swarm does not necessarily indicates a larger temblor is on the way.
Certainly, the weekend's quakes were troubling for Imperial County, which is located in one of California's most earthquake prone regions. More than 400 earthquakes have been detected since Saturday evening, according to the U.S. Geological Survey. One local family felt 15 quakes in 21/2 hours.
But for all the ground movement, experts said there is no evidence the earthquake swarms were a precursor to much larger quakes on longer, more dangerous faults. And scientists don't see any immediate signs of added pressure to the San Andreas fault, which is not far from the location of the earthquake swarm.

A baby sea turtle advances towards the ocean waters of a beach in San Diego, El Salvador, on Saturday Oct. 1, 2011.
The director of the turtle conservation program for the El Salvador Zoological Foundation says the 7.4-magnitude undersea quake sent at least three waves at least 30 feet high up the beach and destroyed thousands of nests and just-hatched turtles. It also washed up on about 150 people collecting eggs in order to protect them in special pens hundreds of feet up the beach. The waves injured three.
Program director Emilio Leon said that in the last year and a half the foundation has successfully hatched and released 700,000 turtles from four species at risk of extinction.
During an earthquake swarm, an affected area experiences a rapid-fire series of temblors that are all similarly proportioned, so that no one shock emerges as the obvious source of the rest. According to Julie Dutton, a geophysicist with the U.S. Geological Survey, diffuse clusters like these are far less common than earthquakes that arrive as one big shake followed by a series of smaller aftershocks.
Dutton estimates that the USGS records about 30 to 40 notable swarms a year, compared with 20,000 to 30,000 total earthquakes. Because swarms are rooted in the same kind of plate movements and stresses that cause more traditional quakes, she thinks that a large part of the phenomenon's apparent scarcity is based on semantics.
Swarms "are really hard to characterize," she told Life's Little Mysteries. "It's all the same mechanisms. It's just a different way of finding equilibrium in the environment."
Where did the swarm start?
The current swarm originates just outside of the small farming town of Brawley, Calif., about 30 miles (45 km) north of the state's border with Mexico. According to Dutton, swarms with magnitude ranges close to the current one arrive in that area at the rate of one or two per decade, with the most recent one hitting in 2005.
The 2005 swarm, which topped out with a 5.1-magnitude event, was surpassed by yesterday's high of 5.5, the cut-off magnitude at which seismologists expect to start seeing casualties in developed countries, according to USGS geophysicist Paul Caruso. But there have been no reported injuries from the Brawley quakes, and Caruso said Monday morning saw a considerable slowing in the area's seismic activity.









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