SEGJ Technical Conference

Potential application of microtremor exploration using array with a reference station

Abstract Applicability of microtremor explorations using an array with a reference station to estimation of S-wave velocity profile is investigated in this study. Simultaneous observation of microtremors at a reference station was conducted together with observation in an array. We first calculated cross correlation between the reference station and the stations in the array using seismic interferometric processing of 4000-hour data. Semblance analysis of the cross correlations at the stations in the array was conducted to estimate phase velocity for fundamental and higher-mode Rayleigh waves. The phase velocity is similar to those from conventional data processing at periods less than 2 seconds, while the phase velocity estimated in this method is lower at periods longer than 2 seconds. We also examined variations of the phase velocity with decreasing data duration. The phase velocity at period of 2 second from 6-hour records is similar to those from 4000-hour records indicating a potential applicability of the method in practical exploration work.