关键词: 地震观测, 震中烈度, 地震波衰减, 浅源地震, 三峡地区

Abstract: From the near-field observation of microearthquakes and available data,it can be found that the amplitude of displacement decreases with the epicentral distances. The analysis of S-wave spectrum in the digital records indicates that the Goner frequenty is as high as up to 21.9 Hz, with its maximal power spectrum ranging form 0.5-26 Hz, and that the distribution of seismic intensity,epcentral intensity and the longth of major axis of isoseismic line shows certain dispersion,which results from the effect of the near-field surface. Study of these characteristic effect in question can provide a base of earthquake-proof/resisting engineering for economic construction.

Key words: seismological observation, Eqicentral intensity, seismic wave attenuation, Shallow earthquake, Sanxia area