Bounds on the Average Recurrence Interval of Major Earthquakes Along the Haiyuan Fault In North-Central China
Bounds on the Average Recurrence Interval of Major Earthquakes Along the Haiyuan Fault In North-Central China
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DOI：
10.1785/gssrl.59.3.81
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发表时间：
1988-07
影响因子：
3.3
通讯作者：
Zhang Peizhen;P. Molnar;Zhang Weigi;Deng Qidong;W. Yipeng;B. Burchfiel;Song Fangmin;L. Royden;Jiao Decheng
中科院分区：
文献类型：
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作者：
Zhang Peizhen;P. Molnar;Zhang Weigi;Deng Qidong;W. Yipeng;B. Burchfiel;Song Fangmin;L. Royden;Jiao Decheng
在1920年发生大地震的海原断裂带上，沿着蔡园、少马阴附近的海沟中发现了地表破裂的证据。除1920年地震外，在2590 ± 190年至1525 ± 170年B. P.期间至少发生过一次断层活动，1525 ± 170年以来可能还发生过一次断层活动。陡崖崩积楔在绍马音海沟似乎记录了两个事件发生在1920年前在过去的2200-3700年，但可能有三个或更多的事件。沿海原断层沿着大地震的平均复发间隔可能超过700年，因为1920年海原地震是该地区有史以来唯一一次重大地震。用该断层的全新世滑动速率沿着为8 ± 2 mm/年，用我们以前的研究所确定的与过去大事件有关的平均偏移量8 m，则由此产生的地震复发间隔将为800 ~ 1400年。从我们的战壕和历史记录的结果是与这个范围相一致的。
Evidence of surface rupture has been found in trenches near Caiyuan and Shaomayin along the Haiyuan fault, where a great earthquake occurred in 1920. In addition to the 1920 earthquake, faulting occurred at least once between 2590 ± 190 years and 1525 ± 170 years B.P. in Caiyuan, and there probably was another event since 1525 ± 170 years B.P. The formation and later tilting of fault-related, scarp-derived colluvial wedges in the Shaomayin trench appear to record the occurrence of two pre-1920 events in the last 2200–3700 years, but there could have been three or more events. The average recurrence interval for great earthquakes along the Haiyuan fault probably exceeds 700 years, for the 1920 Haiyuan earthquake is the only major event to have been reported in this area in as many years of recorded history. Using a Holocene slip rate along this fault of 8 ± 2 mm/yr, and 8 m as the average amount of offset associated with past great events that have been determined by our previous studies, the resultant earthquake recurrence intervals would be from 800 to 1400 years. The results from our trenches and the historic record are consistent with this range.