2000年6月4日印度尼西亚苏门答腊南部M_s8.0地震的震源机制
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摘要
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.
Moment tensor solution of the June 4, 2000 southern Sumatra, Indonesia, Ms8. 0 earthquake is estimated from teleseismic body waves recorded by long period seismograph stations of the global seismic network. This solution is more reasonable than those reported by USGS, Harvard CMT and ERI of University of Tokyo. The double-couple component of this earthquake is 1. 5X1021 N·m, the compensated linear vector dipole component is 1.2X1020 N·m, and the explosion component is?5. 9X1019 N·m. The focal mechanism is mainly left-lateral strike-slip, with a small thrust component. Nodal plane I: The strike is 199°, the dip, 82°, and the rake, 5°; Nodal plane II: The strike is 109°, the dip, 85°, and the rake, 172°. Paxis: The azimuth is 154° and the plunge, 2°; T axis: The azimuth is 64° and the plunge, 10°; Baxis: The azimuth is 256° and plunge, 80°. The P-wave forms recorded at different stations show prominent directivity. The directivity shows that the Nodal plane I is the fault plane, and that the earthquake ruptured unilaterally from the northeast to the southwest, nearly perpendicular to the strike of the Java trench.
Moment tensor solution of the June 4, 2000 southern Sumatra, Indonesia, Ms8. 0 earthquake is estimated from teleseismic body waves recorded by long period seismograph stations of the global seismic network. This solution is more reasonable than those reported by USGS, Harvard CMT and ERI of University of Tokyo. The double-couple component of this earthquake is 1. 5X1021 N·m, the compensated linear vector dipole component is 1.2X1020 N·m, and the explosion component is?5. 9X1019 N·m. The focal mechanism is mainly left-lateral strike-slip, with a small thrust component. Nodal plane I: The strike is 199°, the dip, 82°, and the rake, 5°; Nodal plane II: The strike is 109°, the dip, 85°, and the rake, 172°. Paxis: The azimuth is 154° and the plunge, 2°; T axis: The azimuth is 64° and the plunge, 10°; Baxis: The azimuth is 256° and plunge, 80°. The P-wave forms recorded at different stations show prominent directivity. The directivity shows that the Nodal plane I is the fault plane, and that the earthquake ruptured unilaterally from the northeast to the southwest, nearly perpendicular to the strike of the Java trench.
引文
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许力生,陈运泰.1999.1997年中国西藏玛尼Ms7.9地震的时空破裂过程[J].地震学报,21（5）:449～459
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Chen Y T, Xu L S, Li X, et al. 1996. Source process of the 1990 Gonghe, China, earthquake and tectonic stress field in thenortheastern Qinghai-Xizang (Tibetan) plateau[J]. Pure Appl Geophys, 146: 697-715
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Fauzi, McCaffrey R, Wark D, et al. 1996. Lateral variation in slab orientation beneath Toba Caldera, northern Sumatra[J]. GeophysRes Lett, 23: 443-446
Fitch T J. 1972. Plate convergence, transcurrent faults, and internal deformation adjacent to Southeast Asia and the Western Pacific[J].J Geophys Res, 77: 4 432-4 460
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Kennett B LN, Engdahl E R. 1991. Travel times for global earthquake location and phase identification[J]. Geophys J Int, 105: 429-465
Langston C A, Helmberger D V. 1975. A procedure for modeling shallow dislocation sources[J]. Geophys J R astr Soc, 42: 117-130
Newcomb K R, McCann W R. 1987. Seismic history and seismotectonics of the Suda Arc[J]. J Geophys Res, 92: 421-439
Pan T C, Megawati K, Brownjohn J M W, et al. 2001. The Bengkulu, southern Sumatra, earthquake of 4 June 2000(Mw=7. 7): Anotherwarning to remote metropolitan areas[J]. Seism Res Lett, 72:171-185
Tregoning P, Brunner F K, Bock Y, et al. 1994. First geodetic measurement of convergence across the Java Trench[J]. Geophys ResLett, 21: 2135-2138
Zachariasen J, Sieh K, Taylor F W, et al. 1999. Submergence and uplift associated with the giant 1833 Sumatran subductionearthquake: Evidence from coral microatolls[J]. J Geophys Res, 104: 895-919
许力生,陈运泰.1999.1997年中国西藏玛尼Ms7.9地震的时空破裂过程[J].地震学报,21（5）:449～459
Aki K, Richards P G. 1980. Quantitative Seismology. Theory and Methods[M]. San Francisco: W. H. Freeman and Co, 28-119
Chen Y T, Xu L S, Li X, et al. 1996. Source process of the 1990 Gonghe, China, earthquake and tectonic stress field in thenortheastern Qinghai-Xizang (Tibetan) plateau[J]. Pure Appl Geophys, 146: 697-715
Chen Y T, Xu L S. 2000. A time domain inversion technique for the tempo-spatial distribution of slip on a finite fault plane withapplications to recent large earthquakes in Tibetan Plateau[J]. Geophys J Int, 143: 407-416
Fauzi, McCaffrey R, Wark D, et al. 1996. Lateral variation in slab orientation beneath Toba Caldera, northern Sumatra[J]. GeophysRes Lett, 23: 443-446
Fitch T J. 1972. Plate convergence, transcurrent faults, and internal deformation adjacent to Southeast Asia and the Western Pacific[J].J Geophys Res, 77: 4 432-4 460
Katili J A, Hehuwat F. 1967. On the occurrence of large transcurrent earthquakes in Sumatra, Indonesia[J]. Osaka Univ J Geosci, 10:5-7
Kennett B L N, Kerry N J. 1979. Seismic waves in a stratified half space[J]. Geophys J R astr Soc, 57: 557-583
Kennett B L N. 1980. Seismic waves in a stratified half space-II. Theoretical seismograms[J]. Geophys J R astr Soc, 61 : 1-10
Kennett B LN, Engdahl E R. 1991. Travel times for global earthquake location and phase identification[J]. Geophys J Int, 105: 429-465
Langston C A, Helmberger D V. 1975. A procedure for modeling shallow dislocation sources[J]. Geophys J R astr Soc, 42: 117-130
Newcomb K R, McCann W R. 1987. Seismic history and seismotectonics of the Suda Arc[J]. J Geophys Res, 92: 421-439
Pan T C, Megawati K, Brownjohn J M W, et al. 2001. The Bengkulu, southern Sumatra, earthquake of 4 June 2000(Mw=7. 7): Anotherwarning to remote metropolitan areas[J]. Seism Res Lett, 72:171-185
Tregoning P, Brunner F K, Bock Y, et al. 1994. First geodetic measurement of convergence across the Java Trench[J]. Geophys ResLett, 21: 2135-2138
Zachariasen J, Sieh K, Taylor F W, et al. 1999. Submergence and uplift associated with the giant 1833 Sumatran subductionearthquake: Evidence from coral microatolls[J]. J Geophys Res, 104: 895-919
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