海原断裂带M≥6.7地震概率及其震级分布
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摘要
海原断裂是中国西部的一条重要活动走滑断裂带 ,192 0年沿该带发生的 8.5级大震形成了长达 2 30km的地表破裂带和 10m的左旋走滑位移 .近 10余年来 ,国内外学者对海原断裂开展了古地震研究 ,揭示出大量的古地震事件 ,为研究该断裂带上强震复发规律提供了重要的基础资料 .本文利用这些古地震资料 ,采用泊松模型和布朗过程时间模型 (Brownianpas sagetimemodel) ,并考虑海原断裂带 3个段落组合的不同尺度的破裂 (单段破裂、双段破裂和全带破裂 ) ,经加权分析计算得到了海原断裂带未来百年强震 (M≥ 6 .7)复发的可能性及其震级分布 .计算结果表明 ,海原断裂带未来百年M≥ 6 .7地震发生的可能性为 0 .0 35 .
The Haiyuan fault is a major strike-slip active fault in north-central China, along which Haiyuan earthquake with magnitude 8.5 occurred in 1920, and produced a 230 km long surface reupture zone with a maximum left-lateral displacement of 10 m. In recent years, some researchers have studied the paleoearthquake along the Haiyuan fault and revealed a lot of paleoearthquake events. All available information allows more reliable analysis of earthquake recurrence interval and earthquake rupture patterns along the Haiyuan fault. Based on this paleoseismological information, the recurrence probability and magnitude distribution for M≥6.7 earthquake in future 100a along the Haiyuan fault can be obtained through weighted computation, by using Poisson and Brownian passage time models and considering different rupture patterns. The result shows that the earthquake probability of M≥6.7 is about 0.035 in 100-years along the Haiyuan fault.
The Haiyuan fault is a major strike-slip active fault in north-central China, along which Haiyuan earthquake with magnitude 8.5 occurred in 1920, and produced a 230 km long surface reupture zone with a maximum left-lateral displacement of 10 m. In recent years, some researchers have studied the paleoearthquake along the Haiyuan fault and revealed a lot of paleoearthquake events. All available information allows more reliable analysis of earthquake recurrence interval and earthquake rupture patterns along the Haiyuan fault. Based on this paleoseismological information, the recurrence probability and magnitude distribution for M≥6.7 earthquake in future 100a along the Haiyuan fault can be obtained through weighted computation, by using Poisson and Brownian passage time models and considering different rupture patterns. The result shows that the earthquake probability of M≥6.7 is about 0.035 in 100-years along the Haiyuan fault.
引文
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WorkingGrouponCaliforniaEarthquakeProbabilities.2003.EarthquakeprobabilitiesintheSanFranciscoBayRegion:2002to2031[R].USGeolSurvOpenFileRept,03214
国家地震局地质研究所,宁夏地震局.1990.海原活动断裂带[M].北京:地震出版社,229～252
毛凤英,张培震.1995.古地震研究中的逐次限定方法与新疆北部主要断裂带的古地震研究[A].见:《活动断裂研究》编委会编.活动断裂研究(4)[C].北京:地震出版社,153～164
闵伟,张培震,邓起东.2000.青藏高原东北缘的区域古地震研究[J].地震学报,22(2):163～170
冉勇康,段瑞涛,邓起东.1997.海原断裂高湾子地点三维探槽的开挖与古地震研究[J].地震地质,19(2):97～107
宋方敏,汪一鹏,俞维贤,等.1998.小江活动断裂带[M].北京:地震出版社,142～169
张培震,毛凤英.1996.活动断裂定量研究与中长期强地震危险性概率评价[A].见:《活动断裂研究》编委会编.活动断裂研究(5)[C].北京:地震出版社,12～31
张培震,闵伟,邓起东.2003.海原活动断裂带的古地震与强震复发规律[J].中国科学,D辑,33(8):705～713
MatthewsMV ,EllsworthWL ,ReasenbergPA .2002.ABrownianmodelforrecurrentearthquakes[J].BullSeismSocAmer,92:2233～2250
SchwartzDP ,CoppersmithKJ .1984.Faultbehaviorandcharacteristicearthquakes:ExamplesfromtheWasatchandSanAndreasfaultzones[J].JGeophysRes,89:5681～5698
WorkingGrouponCaliforniaEarthquakeProbabilities.2003.EarthquakeprobabilitiesintheSanFranciscoBayRegion:2002to2031[R].USGeolSurvOpenFileRept,03214
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