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用全球地震台网的长周期地震仪记录到的远场体波,反演了2000年6月4日印度尼西亚苏门答腊南部Ms8.0地震的矩张量解.这个解比USGS、Harvard CMT和东京大学地震研究所得到的矩张量解更为合理.该地震矩张量的最佳双力偶分量为1.5X1021Nm,补偿线性矢量偶极分量为1.2X1020N·m,爆炸分量为-5.9X1019N·m.震源机制主要是左旋走滑,带有很小的逆冲倾滑分量.节面Ⅰ走向为199°,倾角为82°,滑动角为5°;节面Ⅱ走向为109°,倾角为85°,滑动角为172°.P轴方位角为154°,倾角为2°;T轴方位角为64°,倾角为10°;B轴方位角为256°,倾角为80°.该地震的P波显示了明显的方向性效应.P波的这种多普勒效应表明,走向199°的节面为断层面.地震是从东北向西南方向单侧破裂的,破裂传播方向几乎垂直于爪哇海沟走向.
The far-field body waves recorded by long-period seismographs of the global seismograph network are used to inverse the moment-tensor solutions of the Ms 8.0 earthquake in southern Sumatra, Indonesia, on June 4, 2000. This solution is better than that of the USGS, Harvard CMT and the University of Tokyo The moment tensor solution obtained by the Institute of Earthquake Research is more reasonable.The best dual couple component of the seismic moment tensor is 1.5X1021Nm, the compensated linear vector dipole component is 1.2X1020N · m and the explosive component is -5.9X1019N · m. The mechanism is mainly left-lateral strike slip with a small component of thrusting slip. The nodal plane Ⅰ has a strike of 199 °, a dip of 82 ° and a sliding angle of 5 °. The nodal plane II has a strike of 109 ° and a dip of 85 °, The sliding angle is 172 °, the azimuth angle of P axis is 154 °, the inclination angle is 2 °, the azimuth angle of T axis is 64 °, the inclination angle is 10 °, the azimuth angle of B axis is 256 ° and the inclination angle is 80 °. Showing a significant directional effect.The Doppler effect of P wave shows that the nodal plane with an angle of 199 ° is fault plane.The earthquakes are unilateral ruptured from northeast to southwest and the propagation direction of rupture is almost perpendicular to the direction of Java trench .