Downhole Instrument Orientations and Near Surface Q Analysis From the SMART2 Array Data

Abstract

Installation of the SMART2 downhole array in Da-Han Industrial School was completed in May 1992. This array contains one free surface station and three downhole accelerometers down to 200 m depth. Thirteen events recorded by this downhole array are used to study the orientations of the downhole accelerometers are N3¢XE, N91¢XE, and N75¢XE, respectively. The near surface Qvalue is calculated by using the records of three events. The result of Q(f)=9.55f^1.06 was obtained from the smoothed power spectrum ratios. The surface ground motions of two events are simulated from the observed downhole records and Q value we obtained by using the Haskell method. The results confirm the downhole instrument orientations and near surface Q value that we derived in this study.

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