Assessment of earthquake early warning potential from KiK-Net seismograms of 2000-2011 north and east Japan events

摘要

An earthquake early warning alert system with a high degree of accuracy and precision and measured in seconds is a necessity to save many lives in Japan, one of the most tectonically active countries of the world. In this paper, we estimate the potential value for early warning of crustal and intraslab earthquakes recorded at the KiK-Net network. The work reported here is similar to that of the early warning analysis system of California and uses new comprehensive data from northern and eastern Japan (Hokkaido and Tohoko). An attempt was also made to analyze whether the slopes of the regression lines obtained for Californian events (all are crustal events) are similar to those obtained for Hokkaido and Tohoko crustal events. We also analyzed whether there was any difference between the slopes obtained fromJapanese crustal and intraslab earthquakes. The poor correlation of the higher magnitude (> 5.5) with predominant period implied quite a limited predictability of predominant frequency. This was evident from the scattered plot obtained for higher magnitudes. These limitations led us to use a discrete wavelet transform-automated algorithm based on the bi-orthogonal construction with two and four vanishing moments for the primal and dual wavelets.