Posted on 05/01/2008 8:04:18 AM PDT by blam
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. A quake with a magnitude of 6 can cause severe damage, while one with a magnitude of 7 can cause widespread, heavy damage.
"This is an exceptionally vigorous sequence of earthquakes," Price said.
During the past week alone, more than 500 occurrences have been recorded.
Most recently, two measuring 3.1 and 3.2 in magnitude occurred around 11 p.m. Monday. Another 3.1 was recorded at 9:15 a.m. Tuesday.
The largest so far was a 4.7 quake that was registered at 11:40 p.m. Friday. It was preceded 11 seconds earlier by a 3.3 quake, and followed 3 minutes later by one registering 3.4.
The temblors sent goods flying off shelves, cracked walls, broke glass, and collapsed part of a water flume west of Reno. There were no injuries.
They are mostly shallow, occurring just beneath the surface to within a mile or two.
"Shallow makes us believe this is absolutely not volcanic," Price said.
"Needled by Earthquakes"
Mapping of the quakes shows they are clustered around the Mogul and Somersett neighborhoods in northwest Reno, in an area about 2.5 miles (4 kilometers) long and 0.33 mile (0.5 kilometer) wide (see map of Nevada).
Craig dePolo, with the Nevada Bureau of Mines and Geology, said he understands the anxiety of residents who have lived with the persistent shaking.
"What's going on is extraordinary," he agreed. "People are being needled by little earthquakes ... for months."
"And the best we can say is we don't know what's going to happen."
DePolo, who said he's been through many earthquakes, acknowledged that he, too, is "a little nervous."
The governor and emergency managers urged residents to be prepared by strapping down water heaters or any heavy items that could fall and injure people and to have first aid and food provisions on hand.
Frank Siracusa, head of the Nevada Division of Emergency Management, said state, regional, and local agencies train constantly for disasters and have been in daily contact.
"I'd like to say we're prepared, but we can never be too prepared," he said.
The governor said he's "very concerned about the safety of the public" and stressed that residents need to be prepared to minimize risk in the event of a disaster.
Gibbons, himself a geologist, said the earth's movement is what makes the mountains and Nevada landscape special.
"I find it fascinating about our Earth and how it continually evolves over time," he said.
But with Nevada being the second most seismically active state in the continental U.S., he echoed the advice of experts who said large earthquakes are inevitable.
"At some point ... we are going to have a magnitude 6 or 7," Gibbons said.
Better a lot of small ones than one big one.
That was a great movie!!!
Apparently ALGORE does not do Rock & Roll.
Michael Moore has real estate in Reno?
"In the afternoon I joined my wife and son, who were watching the sheep, and inquired if anything new had occurred, since for two weeks we had felt strong tremors in the region. Paula replied, Yes, that she had heard noise and thunder underground. Scarcely had she finished speaking when I, myself, heard a noise, like thunder during a rainstorm, but I could not explain it, for the sky above was clear and the day was so peaceful, as it is in February. "At 4 p.m., I left my wife to set fire to a pile of branches when I noticed that a grotto, which was situated on one of the knolls of my farm, had opened ... and I saw that it was a kind of fissure that had a depth of only half a meter. I set about to ignite the branches again, when I felt a thunder, the trees trembled, and I turned to speak to Paula; and it was then I saw how, in the hole, the ground swelled out and raised itself two or two and one-half meters high, and a kind of smoke or fine dust -- gray, like ashes -- began to rise up in a portion of the crack ... Immediately more smoke began to rise, with a hiss or whistle, loud and continuous, and there was a smell of sulfur. I then became greatly frightened."
The birth of Parictin Valcano in Mexico.
It is all those super secret government underground weapons tests.
darn - "hollow" means there's probably not a bunch of creamy filling inside...like I was hoping for. yummmm....donuts......(I'd do a jpeg of Homer Simpson...but I'm too lazy)
From a political perspective best we keep in mind that Reno is the only thing that keeps Nevada a red state. It’s a solidly Republican area and offsets weakness elsewhere.
If Reno gets evacuated for any reason, we will lose Nevada’s EVs.
“Better a lot of small ones than one big one.”....
Exactly!....I say the same thing in the bathroom!
Snowing in Salt Lake City, too. Oh, and it’s May 1 here, too. ;-)
In the airy vapid voice of the local enviro-whacko....
“Giai, the earth goddess, is upset at us for the way we treat her, and she is letting us know.”
Well, atleast that is how the enviro-whacko I work with explained it.
I just came in here to say “Bush’s Fault”.
That is all.
*ping*
Though I would have usually removed my snow tires by now, I’m headed to MT, ND, SD and WY next week, so they will remain mounted for possible needed use. Al Gore is toast, stick a fork in him.
Keep your snow tires on. We are expecting between one to three FEET of snow in the next two days. (Black Hills of So. Dak.)
I thought of this, too. I wonder. . .
call the cops
Me too....I thought maybe she'd gone off her meds.
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