A 1995 earthquake near Kobe, Japan pushed government and industry to develop an earthquake early warning system (EWS) that helped save lives in the massive March 11, 2011 quake. California is only now beginning development of a similar but smaller scale system, which won’t be ready for four or five years.
The 1995 Kobe earthquake measured 6.8 M with shaking lasting 20 seconds. It claimed over 6,000 lives, collapsed over 200,000 buildings and left 300,000 homeless. The death toll captured the attention of the Japanese government and galvanized government and industry to act.
The quake’s devastation helped create the political will and economic commitment to build an extensive EWS. It is the lack of funding and the absence of a recent major California quake that has hindered development of a California EWS, according to Dr. Elizabeth Cochran, United States Geological Survey (USGS) and Caltech early warning system (EWS) project scientist.
The Japanese EWS, completed in 2007, an 1800-station automated network, provided up to 60 seconds warning to Tokyo residents, 230 miles to the south of the epicenter of the massive 9.0 M Great East Japan earthquake. That warning and ones of lesser duration for areas closer to the epicenter are credited with saving many lives, according to Japanese authorities.
At 2:46:45 p.m. local time, March 11, a seismometer located on land nearest the at-sea epicenter recorded sufficient signals to determine an alert was needed. Then, three seconds later at 2:46:48, the automated system transmitted the alert to Japan’s high-speed train network, factories, schools, TV networks, radio stations and mobile phones. Cell phones received special earthquake alert rings, high-speed trains were slowed, media broadcast warnings of an imminent large quake and workers sought cover. Notwithstanding the warnings and with severe shaking that lasted three to five minutes, the quake claimed nearly 20,000 lives.
What California seismologists are working on at this time are ways to provide comprehensive information as quickly as possible during and immediately after significant earthquakes. Dr. Tom Heaton of Cal Tech is part of a team working to develop computer algorithms that will analyze earthquake waves while the earthquake is still rupturing. This will allow a short-term warning to be broadcast to regions that are about to be shaken by seismic waves that are moving toward them.
What is planned is an eventual network of 400 monitoring stations throughout California that will use those algorithms to communicate early warnings. “The money is not there [for a 1,800-unit network],” said Cochran. “There is agreement at all levels that this needs to happen and that we need to have the technology but we’ll need $80 million over the next five years to have one in place.
“After the Kobe [Japan] earthquake, a lot went into general earthquake research and development. The last component was the early warning system,” Cochran added. Greater funding levels in California for earthquake science and an EWS are not now available. “It’s something that will happen after the earthquake,” she predicted.
Cochran explained that USGS will send warnings to a variety of recipients including state, private industry and media, which will in turn send out warnings through their own systems. A potential but unavoidable pitfall, according to Cochran, is that each organization will have the right to decide whether to communicate the data. “The companies [and state agencies] will have to decide how and when to communicate the warnings,” observed Cochran. “That is how our earthquake projects work. It’s highly individualized. Our goal is to provide the [warning] information.”