Modelling of Strong Ground Motions from 1991 Uttarkashi, India, Earthquake Using a Hybrid Technique

摘要: We present a simple and efficient hybrid technique for simulating earthquake strong ground motion. This procedure is the combination of techniques envelope function (Midorikawaet al. Tectonophysics 218:287–295, 1993) composite source model (Zenget Geophys Res Lett 21:725–728, 1994). The first step based on construction large by superposition functions smaller earthquakes. earthquakes (sub-events) varying sizes are distributed randomly, instead uniform distribution same size sub-events, fault plane. accelerogram event then obtained combining with band-limited white noise. low-cut frequency noise chosen to correspond corner target magnitude high-cut Boore’s fmax or desired simulation. Below frequency, fall-off slope 2 in accordance ω2 model. requires parameters such as area, orientation fault, hypocenter, stress drop, rupture velocity, duration, source–site distance attenuation parameter. fidelity has been demonstrated successful modeling 1991 Uttarkashi, Himalaya (Ms 7). acceptable locations sub-events plane have determined using genetic algorithm. main characteristics simulated accelerograms, comprised duration shaking, peak acceleration Fourier response spectra, are, general, good agreement those observed at most sites. At some sites accelerograms differ from ones factor 2–3. local site geology topography may cause difference, these effects not considered technique. advantage lies fact that detailed velocity-Q structures empirical Green’s required records actual time history past available. method find its application preparing wide range scenarios provides information complementary available probabilistic hazard maps.