Reno area earthquakes

[masaji79]

The Reno area was hit by more than 100 earthquakes in the past several days, the largest being 4.1 and 4.7. The largest since the 1950's. Now the news are telling people to prepare for a larger one. Does anyone really think that there will be a larger earthquake?

[flwxwatcher]

It wouldn't surprise me.

[HurricaneBill]

I think it could go either way.

[masaji79]

Seems like there has been a lot more activity lately on the west coast.

http://earthquake.usgs.gov/eqcenter/rec ... 2.-120.php

[lurkey]

Quakes Keep Shaking Reno; Scientists Stumped
Sandra Chereb in Reno, Nevada
Associated Press
April 30, 2008
Scientists at the University of Nevada, Reno, are scrutinizing seismic readings and studying damage at residents' homes to try to figure out what's happening beneath Earth's surface under a northwest Reno neighborhood rocked by a seemingly endless string of earthquakes.

What they can't say is whether the hundreds of temblors that have rattled the area for two months—the largest a magnitude 4.7 Friday night—are subsiding or a prelude to bigger things to come.

"You're not going to get an earthquake prediction today," John Anderson, director of Seismology Laboratory at the University of Nevada, Reno, said Tuesday during a briefing with Governor Jim Gibbons and emergency managers on the seismic activity.

Scientists are calling the swarm of temblors that began February 28 the "Mogul earthquake sequence," in reference to the neighborhood where hundreds of mostly minor earthquakes have occurred.

But the shaking is unusual, seismologists say, because the intensity of the quakes has increased over the past few weeks. Generally, earthquakes tend to occur and are followed by smaller aftershocks.

In this case, the earth's rumblings have continued unabated, with barely negligible bumps occurring often minutes apart, followed by occasional larger shakers.

It's impossible to know if the temblors are foreshocks of a bigger quake to come or aftershocks of what has been, experts said.

Day After the Day After Tomorrow?

Up until April 15, sizable quakes that could be felt were occurring about once every third day.

Then the rate increased, with about three, 2.0 or larger incidents occurring daily.

On April 24, when the first 4.2 quake was registered, "all of a sudden we were seeing 20 [of the magnitude] 2s and larger per day," said state geologist Jon Price.

Earthquake magnitudes are calculated according to ground motion recorded on seismographs. An increase in one full number—from 5.5 to 6.5, for example—means the quake's magnitude is 10 times as great.

Page 2 here

[masaji79]

Magnitude 3.9 - NEVADA
2008 June 08 17:55:19 UTC

Earthquake Details
Magnitude 3.9
Date-Time Sunday, June 08, 2008 at 17:55:19 UTC
Sunday, June 08, 2008 at 10:55:19 AM at epicenter

Location 39.552°N, 119.920°W
Depth 1.7 km (1.1 miles) set by location program
Region NEVADA
Distances 5 km (3 miles) NE (37°) from Verdi-Mogul, NV
9 km (6 miles) WNW (288°) from Reno, NV
13 km (8 miles) WSW (248°) from Sun Valley, NV
174 km (108 miles) NE (50°) from Sacramento, CA

Location Uncertainty Error estimate not available
Parameters Nph= 31, Dmin=0 km, Rmss=0 sec, Gp= 0,
M-type=local magnitude (ML), Version=2
Source Seismological Laboratory, University of Nevada, Reno

Event ID nn00248760

This event has been reviewed by a seismologist.

[lurkey]

Earthquake swarm picks up again in northern Nevada

Jun 8, 4:18 PM (ET)

By MARTIN GRIFFITH

RENO, Nev. (AP) - A months-long swarm of earthquakes picked up again Sunday as a string of minor temblors rattled Reno, causing downtown high-rises to sway and knocking items off walls and shelves.

There were no immediate reports of injuries or major property damage after about 20 minor quakes reported on the western edge of Reno over 12 hours ending about noon.

Magnitude-3.9 and 3.7 quakes struck within a couple minutes of each other shortly before 11 a.m. and were preceded by 3.2 and 3.0 quakes early Sunday, said researchers at the seismological laboratory at the University of Nevada, Reno.

Diane dePolo, a lab seismologist, said it was the strongest sequence of quakes in the past month and signaled a pickup in activity after a recent lull.

"We had a little pickup in activity on Tuesday and nothing significant until today," dePolo said. "We are monitoring them, but we can't say if it'll get better or worse. There is no way to predict earthquakes."

Seismologists had urged residents of northern Nevada's largest city to prepare for a bigger event after a 4.7 quake on April 25, the strongest in a swarm that began Feb. 28.

That quake swept store shelves clean, cracked walls in homes and dislodged rocks on hillsides, but there were no reports of injuries or widespread, major damage.

The swarm, which has produced thousands of mostly minor quakes, had prompted some residents in the densely populated quake zone to spend nights outside in campers and trucks.

"We live in earthquake country, and the threat is never over," dePolo said. "We encourage people to be prepared."

Nevada is the third most seismically active state in the U.S. behind California and Alaska. Reno's last major quake measured 6.1 on April 24, 1914.