MAJOR CATASTROPHIC EARTHQUAKE IN SEPTEMBER 2010!!!

[xilman]

[Uncwilly]

6.6 off BC (not Baja California; British Columbia [which is no where near Columbia ]

[science_man_88]

Earthquake of 6.6 magnitude deep in Pacific Ocean south of Fiji - USGS

SINGAPORE, May 4 (Reuters) - An earthquake with a magnitude of 6.6 struck in the Pacific Ocean on Sunday deep in the ocean about 328 miles (525 km) south of Suva, Fiji, the U.S. Geological Survey said.

[kladner]

There seem to have been quite a few ~6.x quakes in the Fiji area lately.

[science_man_88]

Originally Posted by kladner

There seem to have been quite a few ~6.x quakes in the Fiji area lately.

yeah 9 of 14 significant earthquakes in the last 30 days on the USGS website are close to fiji.

[science_man_88]

Earthquake cracks walls, roads in north Thailand

The airport in Chiang Rai, a northern Thai city near the epicenter of the shallow magnitude 6.3 temblor, evacuated people from its terminal, where display signs and pieces of the ceiling fell. There was no damage to the runway or flight disruptions, airport General Manager Damrong Klongakara said.

it seems to be downgraded to a 6.0 but still is in the significant category on the USGS.

[LaurV]

I was in the car returning from work, didn't feel a breeze. When I reached home everybody was on the street in my mooban (neighborhood) including my family, and I didn't know why. They said they felt the shaking darn well...

My girls (SWMBO included) were scared and didn't want to go back into the house for a while, they played and talked with other children/people outside. I parked the car, went straight into the house, took a shower and a nap... This morning there was a small aftershock (like a big truck passing on the the street, no shaking), which again I didn't feel, I was still sleeping, SWMBO said she was in the kitchen making breakfast, and she felt the glasses vibrating a bit.

[xilman]

http://www.bbc.co.uk/news/world-latin-america-27335028

[science_man_88]

EARTHQUAKE OF 6.8 MAGNITUDE STRIKES OFF PANAMA - USGS

May 13 (Reuters) - An earthquake of 6.8 magnitude struck off the coast of Panama early on Tuesday, the U.S. Geological Survey reported.

The quake hit the sea, 132 km south of the city of David at 0635 GMT at a depth of 10km, the USGS added.

[ewmayer]

Apparently the great 1906 SF quake was historically unusual in being a one-off:

Earthquake cluster likely to strike Bay Area, scientists say

The Bay Area's Big One will still be plenty big, but it might not be just one, according to a study released Monday by U.S. Geological Survey scientists.

A flurry of mid-sized quakes is more likely to strike the Bay Area rather than a giant 1906-esque rupture, said David Schwartz, a paleoseismologist at the USGS's Menlo Park office and the lead author of the study, which appeared in June's Bulletin of the Seismological Society of America. The study marks the first comprehensive history of the Bay Area's seismicity dating to 1600.

A quake cluster isn't necessarily good news, as it could keep communities constantly cleaning up the earthquake damage, several experts said.

"It presents a very different problem in how you respond and recover from earthquakes," Schwartz said.

After the 7.8-magnitude 1906 earthquake, the 20th century was abnormally stable, he said. Therefore, an earthquake cluster is overdue, the scientists said.

"Basically, what goes in, must go out," Schwartz said. The region's seismicity stems from the clash of two massive plates in the earth's crust. The Pacific Plate is sliding northwest, while the North American Plate is moving southeast.

Since 1906, the plates have moved about 13 feet in the Bay Area. Like a compressed spring, they're ready to burst.

In the Bay Area, the plate boundary fractures into a handful of fissures, all generally trending northwest-to-southeast. The well-known San Andreas Fault, which Schwartz calls the "master fault," is accompanied by the San Gregorio Fault, the Hayward Fault, the Calaveras Fault and the Rodgers Creek Fault in the North Bay, among others.

Future quakes are expected to spread out along these faults."These faults are being stressed by the plate movements... and they all have to catch up," Schwartz said.

The various faults "talk" to each other, said Roland Burgmann, an earth scientist at UC Berkeley. "The communicating family of faults sometimes tend to rupture together as a group or shut each other off."

The 1906 earthquake was likely a fluke, the perfect alignment of conditions that allowed 300 miles of the San Andreas Fault -- from northern Mendocino County to San Juan Bautista -- to release its pent-up pressure. This massive shaking kept the area unusually calm for a century, Schwartz said.

"Eventually, there should be more clusters," Burgmann said.

The scientists based their prediction on the historical record, which shows a cluster of quakes shook the Bay Area from 1690 to 1776. At least six earthquakes, ranging from 6.3 to 7.7 magnitude, rattled the region's major faults during that period, Schwartz said.

The cumulative release of energy from the quakes roughly equals that of the 1906 earthquake, Schwartz said.

"This is a summary of a tremendous amount of work," said Greg Beroza, a Stanford seismologist who was not involved with the study.

Previously, other scientists had scoured the records kept by the Franciscan missionaries at San Francisco's Mission Dolores starting in 1776, Schwartz said. He called the Spanish missionaries "the first seismographers." They described the rumblings in their records, allowing scientists to assess the earthquake's strength by extrapolating from the amount of damage the Franciscans described.

Scientists dated the earlier quakes by digging trenches and calculating the age of charcoal or other organic materials found several feet below the surface, Schwartz said.This technique misses small or deep earthquakes, which don't break the surface.

Much as appreciate the work geologists do, I simply can't associate with them - they're such a fault-finding bunch.

[science_man_88]

Originally Posted by ewmayer

Apparently the great 1906 SF quake was historically unusual in being a one-off:

Earthquake cluster likely to strike Bay Area, scientists say

Much as appreciate the work geologists do, I simply can't associate with them - they're such a fault-finding bunch.

one thing I like about the quote:

The scientists based their prediction on the historical record, which shows a cluster of quakes shook the Bay Area from 1690 to 1776. At least six earthquakes, ranging from 6.3 to 7.7 magnitude, rattled the region's major faults during that period, Schwartz said.

The cumulative release of energy from the quakes roughly equals that of the 1906 earthquake, Schwartz said.

using these as though on the moment magnitude scale I get an average energy of roughly a 7.3 quake.