浅源走滑大震震源过程的某些特征

本文给出了邢台、海城、唐山三大地震的震源机制研究结果,并结合其它大震资料,对浅源走滑大震震源过程的特征作了初步探讨.这类地震的P波波形一般都较复杂,可用单断层多重破裂或复断层多重破裂作解释.地震震级愈大,其第一子震的震源持续时间和破裂长度都愈长.发生在活动频繁、贯穿性好的深大断层上的地震与发生在无明显大断层地区的地震相比较,前者的应力降和位错上升速度都比后者的偏低,而且这种差别在第一子震上表现尤其明显.

SOME CHARACTERISTICS OF SOURCE PROCESSES OF LARGE SHALLOW STRIKE-SLIP EARTHQUAKES

Source mechanisms of the Xingtai （Mar. 8, 1966）, Halicheng （Feb. 4, 1975） and Tangshan （July 28, 1976）, earthquakes were studied in this paper. By combining the results of these three events with those of other events studied earlier, we investigated the characters of source processes of large shallow strike-slip events. In general, their P waveforms are very complex caused by either the multiple-subevents on the single fault or the multiple-subevents on the, multiple-faults. A large magnitude Mw associates with a long duration and a long ruprture length of the first-sub event. It appears that the earthquakes which occurred on the more apparent and through going active faults have first-subevents with lower stress-drops and lower dislocation-rise-velocities than those not on it.