Earthquake early warning in the PNW
December 1, 2011
by John Vidale
Tuesday, it was announced that three West Coast universities, UW, Caltech, and Berkeley, will split $6M to allow a big step forward in the science and implementation of earthquake early warning.
The March 2011 earthquake in Japan, despite its tremendous costs, has shown clearly the value of a new line of defense against natural distasters. Seismometers detected the earthquake with seconds, automatic computer programs estimated the shaking that it would soon produce, and people received warning seconds to minutes before the shaking arrived.
The warnings were broadcast on TV. EEW systems have been installed or are being tested many places around the world. The figure (Allen et al., SRL, 2009) shows the status of EEW systems two years ago.
There are many ways earthquake early warning could be used on the west coast - slowing traffic, clearing vulnerable structures such as large bridges and viaducts, giving people a heads-up. Perhaps a subtle but important benefit is for people to immediately realize most bumps and noises are NOT the sound of the start of a nasty earthquake.
There is already at least one structure wired for early warning in Seattle - the Alaska Way Viaduct - whose gates will close at the beginning of strong shaking, but a more extensive system wired to seismometers closer to the faults on the coast could perform better.
Such a system would be costly - roughly $60M and $6M/yr to install and operate. With the new grant, we would build much less than the full system. So far we are still puzzling over the myriad details that would need to be done right for a reliable, accurate, widely available, and properly used system. This site has more details focused on California.