Estimated and Timely Updated Shake Mapping for Earthquake Early Warning by Interpolation of the Processed Values from Geometric Distribution of Stations

Abstract:

For the rapid reaction against the destructive earthquake hazard, the earthquake early warning system is one of the most challenging methods even though the lead times are very short as few seconds. In the operation of earthquake early warning (EEW) it is important to quickly determine which region is expected as the damaged zone using the estimated and observed information such as location of epicenter, magnitude and PGA of seismic stations. This research is about generating the estimated and timely updated PGA shake map using two different ways: one is from the estimated PGA values using attenuation relation between magnitude and epicenter distance referring to the results of EEW and the other is from the observed PGA data with updating every second from seismic stations. The timely updated shake map can be calculated on every grid of national wide area with 0.1 degree grid size using Modified Shepard interpolation with processing the observed PGA data by EEW system receiving 100 sps data from stations. The estimated shake map is also calculated on the same grids and with the same interpolation as like the observed shake map, and could be updated promptly when EEW system changes the epicenter or magnitude as gathering data. These shake maps has been under testing with operation of EEW in Korea from the early 2013 and the performance of calculation has been stable even though it has to work continuously for a long time. The realistic values should be considered by applying amplification factors at every station in the further study.