Analysis of phase property of earthquakes observed by vertical instrument arrays at JAEA Oarai site

Sugino, Hideharu*; Onizawa, Kunio 

Regression models of group delay time have been established by analyzing Earthquake Observation database obtained from Vertical Instrument Arrays at the Oarai Research and Development Center of Japan Atomic Energy Agency. It is known that the mean value and standard deviation of group delay time obtained by differentiating the Fourier phase spectrum show the center of gravity position and continuous time in earthquake time history. Therefore the regression model of the mean value and standard deviation of group delay time was made as function of the magnitude and the epicentral distance. This model includes the source and propagation of earthquake around the site. It is expected that the development of seismic motion prediction method considering the site's phase property by using this regression model.