Taiwan, Japan scientists claim breakthrough in earthquake warning (Roundup)

Apr 6, 2009, 9:31 GMT

   Taipei - Taiwanese and Japanese scientists have made a breakthrough in earthquake early warnings, allowing the public to be alerted 10 to 30 seconds before a major quake causes destruction, a newspaper said Monday.

   The breakthrough was achieved by Wu Yih-min, associate professor in the Department of Geosciences of the National Taiwan University, and Professor Hiroo Kanamori at Seismological Laboratory at the California Institute of Technology, the China Times said.

   It can give people more time to seek safety, as currently the quickest alert Taiwan's Seismological Observation Centre can give is 30 seconds after a quake has struck, it added.

   'Our research is to give the early warning as early as possible so that people can take precaution. Currently seismologists still cannot predict an earthquake, but we hope our research can help seismologists of future generations to predict earthquakes,' he told the German Press Agency dpa.

   According to Wu, after an earthquake has occurred, it sends out P-waves and S-waves. P-waves are the less destructive vertical waves, while S-waves are devastating horizontal waves.

   As P-waves travel 1.73 times faster than S-waves, Wu worked out the correlation between the P-waves and the magnitude of the quake, which means that by analyzing the characteristics of P-waves, he can gauge the destructive force of the quake.

   Wu and Kanamori's study, which began in 1999, is financed by the Taiwan's National Science Council and Seismological Observation Centre. They tested the method at the South California earthquake monitoring network in 2007 and have been testing it at the Pacific Tsunami Warning Centre in Hawaii since 2008.

   Tests in California showed that after an earthquake, four to six monitoring stations recorded features of the P-wave within seven seconds after the quake had struck. Adding the time of computer transmission, a warning could be sent out 10 seconds before a quake starts to cause damage.

   The China Times said that Wu and Kanamori's method can prevent or cut property damage or loss of life because 10 seconds is enough time for someone to switch off a gas stove, for a bullet train to slow down or for a nuclear power plant's reactors to be shut.

   Currently the quickest earthquake early warning in the world is issued by Japan's Meteorological Agency, which - by using the Nowcast early-warning method - can issue the alert three to four seconds after an earthquake has occurred.

   Taiwan's Seismological Observation Centre can measure earthquake magnitude no sooner than 18 seconds after the quake begins. Measuring the magnitude and sending out the warning takes at least 30 seconds.

   Wu and Kanamori plan to develop a beeper-like gadget, called a Mems Sensor, so that people can receive early warnings from the Seismological Observation Centre after a strong quake has struck.

   Wu and Kanamori published their paper, Development of an Earthquake Early Warning System Using Real-Time Strong Motion Signals, in the Swiss journal Sensors in 2008, and the research has attracted attention from many countries.

   Taiwan's Seismological Observation Centre said it will not adopt Wu's method until the accuracy of his earthquake early-warning system can be proven, the China Times said.

   The centre uses the more conservative front-detection method which takes longer to issue a warning but provides more accurate data.

   Taiwan sits on the circum-Pacific seismic belt and experiences about 18,500 earthquakes each year. Of these, only some 1,000 quakes can be felt by human beings.

   On September 21, 1999, an earthquake measuring 7.3 on the Richter scale struck in Taichung County, central Taiwan, killing 2,400 people and injuring more than 10,000 people.