川西则木河断裂带强震复发周期的初步研究

本文从地震活动性和断层活动性两方面初步研究了川西则木河断裂带上地震的复发周期。通过古地震地貌现象的研究,发现则木河断裂北段西昌一带自晚更新世以来多次发生强震,其中全新世时期至少有4次。并得出晚更新世时期,强震在原地重复的周期为2000年,全新世时期为1800年,则木河断裂带滑动速率的研究表明,晚更新世时期断层滑动速率为4.5mm/a,全新世时期为4.9mm/a,以此估计则木河断裂带上晚更新世时期,强震重复的平均周期为965—1380年,全新世时期为885—1275年。

PRELIMINARY STUDY ON THE RECURRENCE PERIOD OF STRONG EARTHQUAKES ON THE FRACTURE ZONE OF ZEMUHE, WEST OF SICHUAN

The earthquake recurrence period of Zemuhe fracture zone in the west of Sichuan was studied from both the seismic activities and fault activities. It is found that there have been a lot of strong earthquakes occurred in Xichang, north segment of Zemuhe fracture zone since Late Pleistocene epoch, and at least 4 events in Holocene epoch through the studying of geomorphic feature of paleoearthquakes, from which we got to know that the recurrence period of strong earthquakes in the primary site is about 2000 year in Late Pleistocene and 1800 year in Holocene. It is obtained by calculating the slipping rate of Zemuhe fracture zone that the fault slipping rate is 4. 5mm/a in the period of Late Pleistocene epoch and 4. 9mm/a in that of Holocene, thus we know that the average recurrence period of strong earthquakes of Zemuhe fracture zone is 965-1380 year in Late Pleistocene epoch and 885-1275 year in Holocene.