武定6.5级地震序列震源机制
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摘要
由地震Ｐ波初动符号资料，求解得到１９９５年１０月２４日武定６５级地震序列主震及２１个强余震的震源机制解。主震的两个节面走向分别为北西西向（２８２°），倾向ＮＮＥ，倾角７０°；另一个节面走向为北北东（７°），倾向Ｗ，倾角７７°；等效释放应力场主压应力方位为３２４°，仰角２４°。根据地质资料、等震线形状及余震震中分布选取ＮＮＥ（７°）向节面为主震发震断裂，该断裂面在南南东向接近水平的应力场作用下，以左旋走滑错动为主，略具张性。主震等效释放应力场主压应力方位与本区区域应力场主压应力优势方位（３２５°—３５５°）基本一致。截止到１１月１０日的强余震震源机制解绝大数与主震相似，结果较稳定，主压应力方位与主震主压应力方位之差小于２０°，断层面错动性质与主震断层面错动性质一致。余震序列震源机制结果表现为较统一稳定的特征。表明与区域应力场基本一致的主震震源应力场及发震断裂控制着整个序列的地震活动。
Unprecedentedly great deformation variation occurred at fixed point of Yongsheng seismostation and the deformation variation in WE direction was remarkably larger than that in NE direction before the Lijiang earthquake,which displays a typical earthquake example of striking varation of fixed point deformation near focla region before large earthquake with M 7 0, having imortant reference significace to researching anomaly characteristics near observation points before large earthquake in the future.
Unprecedentedly great deformation variation occurred at fixed point of Yongsheng seismostation and the deformation variation in WE direction was remarkably larger than that in NE direction before the Lijiang earthquake,which displays a typical earthquake example of striking varation of fixed point deformation near focla region before large earthquake with M 7 0, having imortant reference significace to researching anomaly characteristics near observation points before large earthquake in the future.
引文
〔1〕阚荣举等，我国西南地区现代构造应力场与现代构造活动特征的探讨。地球物理学报，1977，2〔2〕1995年云南武定65级地震灾害损失预估结果〔3〕魏柏林，余震震源机制变化的原因，地球物理学报，19801〔4〕王绍晋等，禄劝地震序列震源机制，地震研究，1985年，增刊〔5〕晏凤桐等，禄劝地震的类型分析，地震研究，1985年，增刊〔6〕陈，用震源机制一致性作为描述地震活动性的新参数，地球物理学报，1978
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