Earthquake sensors mapping Napa to better predict seismic damage

NAPA, Calif. (KTVU) - Come the week of September 7th, the US Geological Survey will use buried mini-explosives, to generate a swarm of almost undetectable, underground earthquakes in the city of Napa.

Though the quakes will be small, the data gathered from them will have big benefits for earthquake damage predictions.
 
Two years ago, David Graves and Elizabeth McKinne's Victorian home, near downtown Napa, was badly damaged. Though the epicenter was 10 miles south of town, the damage to central Napa was far greater than existing fault and shaking maps predicted. So, they are allowing their backyard to be used to house a couple of some 900 sensors that will be placed throughout the town about a hundred yards apart.

The sensors will gather data from a series of mini explosive generated mini quakes to produce a detailed map of the subsurface which will give scientists new insights into how earthquakes work.

"I believe that the more you know the less fear you'll have really.  I think knowledge is power." says homeowner McKinne.

The sensors are so sensitive that the mini quakes will have to be created in the dead of night when there's less vibration like traffic around and the reason for that is simple.  Even dropping a set of keys creates enough of an earthquake to overwhelm these sensors.

The US Geological Survey is partnering with UC Eastbay to set the sensors and gather the data. "Nine hundred sensors is significant for the whole Bay Area not just for this area," says Rufus Catchings, a USGS geophysicist.

"The things we're gonna find here, we're gonna be able to create a model that more accurately measures the shaking we saw; the difference between what we predicted and what we're gonna see with an updated model," says
Professor Luther Strayer, California State University Eastbay geologist.

The information can help update and improve other models in other places.

"We can look for those same type of things, anyplace, worldwide and see if those same things are happening," says geophysicist Catchings. “All of coastal California is really under threat from damage from earthquakes.  So, I think the more we know, the better prepared we can be, the less loss of life there will be, the less property damage.  It will be easier t recover and I think that's really important," says homeowner David Graves.

The first results will be released in December.