April 4, 2011
Earthquake scientists discuss West Coast earthquake early warning system
Earthquake scientists from Washington, Oregon and California are meeting this week to discuss the feasibility of establishing an earthquake early warning system for the West Coast similar to the one that gave a valuable heads-up in the recent giant quake in Japan.
Such a system would place seismic monitors in a dense arrangement in fault zones and could begin sending warnings of impending ground shaking within 5 seconds after an earthquake is detected by the nearest seismometer.
“When the Cascadia subduction zone ruptures again, this system could provide four minutes of warning, in an ideal case, that strong shaking is headed to the population centers of western Washington and Oregon,” said Bill Steele, coordinator of the University of Washington seismology laboratory. “It also could help speed tsunami warnings to coastal communities.”
The Cascadia subduction zone is capable of producing huge earthquakes such as the one in Japan, and last did so in 1700. For the Northwests more common deep earthquakes, alerts could arrive tens of seconds before the strongest shaking. People living near a shallow crustal earthquake would not get much notice, but those living some distance away would receive a small warning.
Even a warning of 30 seconds could be enough for a doctor to halt surgery, for a factory to shut down sensitive equipment, for a train to stop before it reaches a vulnerable bridge or for controllers to prevent planes from landing or taking off. That could save many lives and potentially prevent millions of dollars in damage.
The seismometer network would begin sending data on ‘P waves, non-destructive waves generated by an earthquake that travel through the Earths crust faster than do secondary waves that can cause great damage.
The scientists say the warnings likely would begin as underestimates of ground shaking but would become more accurate as long as the earthquake continues to grow.
West Coast earthquake scientists are meeting Monday and Tuesday at the University of California, Berkeley. They will explore how such a system would work, what it could accomplish and how much it might cost, said John Vidale, a UW professor of Earth and space sciences and director of the Pacific Northwest Seismic Network.
The UW is involved in planning, but also would be instrumental in improving the seismic sensor and communications network. A system likely would be established in California first, and the Pacific Northwest would be added as issues with the system are ironed out.
But scientists up and down the coast would be working together to make the system work, Vidale said.
“Wed all be sharing the data, because the faults dont stop at the state borders, or at national borders,” he said.
Steele noted that the system would have to be integrated with local emergency management efforts to be effective, because individual emergency managers have the best knowledge of actions to take in their locations.