Tuesday, July 17, 2012

No. 564: Using the GPS for the prediction of an earthquake (July 17, 2012)

Geospatial Information Authority of Japan (GSI) and Tohoku University jointly developed a system to estimate the scale of an earthquake and the height of a tsunami using the global positioning system (GPS) much faster than the existing system. Based on the data on crustal movements coming from about 1,200 land GPS observation points across the country, the new system determines the variation caused by an earthquake and sends estimates to Japan Meteorological Agency in a few minutes. It will be put into operation within the year. The existing system needs data that cover as much as three hours and five hours to produce observational results.

Using the analytical approach developed by Tohoku University, the new system observes the amount and direction of crustal movements to a precision of 10 cm using data coming in every second, and figures out the variation of the fault and bedrock caused by an earthquake. Japan Meteorological Agency receives data dispatch by GSI and calculates the scale of an earthquake and tsunami using computer. GSI is improving the new system for even higher precision to start sending data to Japan Meteorological Agency within the year. Currently, the agency calculates the scale of an earthquake and the height of a tsunami using data from a seismograph. It tends to underestimate the scale of an earthquake of magnitude higher than 8.0, but the new system hardly underestimate an earthquake. In addition, because the new system can calculate the variation of the seabed, it is suitable for the measurement of a large ocean-trench earthquake. 

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