摘要
利用地面垂直形变测量资料研究了1990年4月26日青海共和Ms6.9地震的震源机制。通过反演得出这次地震是由逆冲倾滑为主的断层错动引起的。该断层走向102°,倾向SW,倾角46°,长40km,宽9km,断层上部边界至地面的垂直距离3km,下部边界至地面的垂直距离10km。逆冲倾滑错距79cm,伴以错距5cm的左旋走向滑动。这是一次低应力降(3.8MPa)的板内地震,应变降为5.7×10^(-5),地震矩9.8×10^(18)N°m,能量释放5.0×10^(14)J。由反演得到的共和地震的震源机制与等震线的形态、余震的空间分布以及共和盆地断层交汇的特征总体上是一致的。
The focal mechanism of the Gonghe Ms 6.9 earthquake of Qinghai, China in April 26,1990 is inverted using leveling data. It is obtained through inversion that this earthquake is caused by a amainly reverse dip-slipping fault. The fault strikes 102°, dips to SW and dip angle is 46°. The fault length and width are 40 and 9km respectively. The upper bound of the fault is 3km underneath the groundsurface and the lower bound, 10km. The reverse dip-slip and the left-lateral strike-slip components of the dislocation are 79 and 5cm respectively. This is a low stress drop (3. 8 MPa) intraplate earthquake, with strain drop estimated to be 5.7×10^(-5). The seismic moment is 9.8×10^(18)N·m, and the energy release is 5.0×10^(14) J. This focal mechanism is generally consistent with overall distribution of isoseismals, aftershock seismicity and geometry of intersecting faults structure in the Gonghe basin.
出处
《地壳形变与地震》
CSCD
1992年第4期1-11,共11页
Crustal Deformation and Earthquake
关键词
地震
震源机制
水准测量
青藏高原
focal mechanism, leveling survey, Gonghe earthquake, inversion, intraplate earthquake, Qinghai-Tibetan Plateau
