2012 年6 月30 日新疆新源-和静MS 6. 6地震序列震源机制解

The focal-mechanism solution of the Xinyuan-Hejing MS6. 6 earthquake in Xinjiang on June 30，2012

摘要:

利用CAP 方法反演了2012 年6 月30 日新源－ 和静MS6． 6 地震序列震源机制解。反演得到MS6． 6 地震节面Ⅰ的参数为:走向299°，倾角68°，滑动角164°;节面Ⅱ的参数为:走向35°，倾角75°，滑动角23°;P 轴方位角166°，倾角5°，T 轴方位角258°，倾角26°;矩震级Mw 为6． 3;矩心深度为21km。此次地震序列破裂优势方向为NWW，倾角以60° ～ 90°为主，滑动角以± 180° ± 30°为主;P 轴方位的优势取向为近NS 向，T 轴优势取向为近EW 向。初步分析表明，主震节面Ⅰ为发震断层，是走向为NWW、近乎直立的左旋走滑断层。此次6． 6 级地震震源断错性质和主压应力方向以及序列P 轴优势方位与震源区周围构造应力场特征基本一致。

Abstract:

Using the CAP method to invert the focal-mechanism solution of the Xinyuan-Hejing MS6． 6 earthquake on June 30，2012． The result shows that the best double couple solution of the MS6． 6 event is 299°，68° and 164° for strike，dip and rake angles respectively． The other nodal planes are 35°，75° and 23°． The azimuth and dip angle of P axis are 166° and 5°，those of T axis are 258° and 26°． The moment magnitude is 6． 3． The estimated focal depth is about 21km． The predominant rupture direction of this seismic sequence is NWW． The dip angles are between 60° and 90°． The rake angles are basically ± 180° ± 30°． The predominant strike of the azimuthal angle of P axis is near NS and T axis is near EW． Preliminary analysis indicates that nodal section． One is the seismogenic fault and NWW-trend and nearly upright left-lateral strikeslip fault． The displacement property and the principal compressive stress of this MS6． 6 earthquake focus and P axis preponderant orientation of this seismic sequence agree with the tectonic stress field＇s characteristics of the focal area around．