METHOD FOR EVALUATING AMPLIFICATION CHARACTERISTIC OF GROUND AT EARTHQUAKE

摘要

PROBLEM TO BE SOLVED: To obtain a cost-reduced highly reliable method for evaluating an amplification characteristic at a strong earthquake. ;SOLUTION: Data of micro motions are stored continuously in real time for 10 units each composed of two components in the horizontal direction and a component in the vertical direction (a1). The data are transformed by FFT to a Fourier spectrum for each component (a2). Data of two horizontal components are synthesized (a3). The horizontal-vertical spectral ratio (H/V-R) is calculated (a7). The data are integrated over a suitable range of a vibration cycle, thereby obtaining a Vi value. The range of the integration is set so that the Vi value corresponds to an amplification rate of a ground obtained from strong quake records of previous earthquakes, whereby the Vi value obtained in a similar integration range at an optical point corresponds with good reliability to the amplification rate of the ground. Since the constant micro-motion can be observed at low cost, an amplification characteristic of the ground in a wide area can be evaluated easily.;COPYRIGHT: (C)1999,JPO