Some Seattleites putting seismometers in their basements

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by GLENN FARLEY / KING 5 News

Bio | Email | Follow: @GlennFarley

KING5.com

Posted on February 11, 2010 at 4:03 PM

Updated Thursday, Feb 11 at 7:00 PM

SEATTLE - The word went out in mid-December: Want seismometer in your house? And people signed up.

More than 1,000 homeowners, businesses and even government agencies volunteered to host a seismometer.

A seismometer is a device that records ground shaking. When a dump truck drives past your house, the seismometer will probably pick it up. But it's really about recording earthquakes, and that motion is recorded as a squiggly line. The more shaking, the taller the line.

There are already hundreds of seismometers that record different ranges of motion around the region. About 300 of them are part of the Pacific Northwest Seismic Network or PNSN, headquartered at the University of Washington in Seattle. But according to PNSN, that's not really enough of the monitors for all the things they want to study, especially in the densely populated Interstate 5 corridor. 

"To capture that, we really need to densify the actual measurements of ground motion we can receive." says U.W. seismologist Bill Steele.

Now comes Netquake, which is building out a grid of seismometers in Seattle, Bellevue, Everett and Tacoma and eventually will be up and down Western Washington and into the Portland Oregon area.

If funding keeps coming it could total out to some 900 instruments. Each seismometer costs about $4,000, but it's seen as a lower cost alternative to the more traditional way of doing things because it's recruiting people to be almost passive volunteers. Sixty volunteers were selected in this the first phase.

The idea is that the host of the seismometer doesn't need to do much other than allow the seismometer access the homes Wi-Fi network to "talk" to computers in the Seismo Lab at the University of Washington, and allow it to hook into the power grid.

When the seismometer indicates its backup batteries are getting low, it phones in and a new battery is automatically sent out to the volunteer, who plugs it in at much less cost than sending a team of experts to the home to install a new battery.

Each seismometer in Netquake will help form a grid about 1 kilometer or six-tenths of a mile apart. The first installations began last week. In the years ahead, the network is expected to grow even denser.

As the network is built out, scientists will get a sharper and sharper picture of the earth, and our vulnerabilities depending on where we live.

Smaller earthquakes, say magnitude 3 or 4, won't bring down houses, but they do provide a rich cache of data to show more accurately the different soil types and how different soils will react in a large quake. For example, could some of that soil liquefy and turn spongy with severe shaking? Could a basin of softer soil between ridges of rock amplify the shaking for a house sitting on that soft soil?

These are the questions Netquake is supposed to help answer, as well as provide highly accurate shaking maps to first responders to determine hot spots - places with the worst damage and more injuries.

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