Accurate hypocentre determination in the seismogenic zone of the subducting Nazca Plate in northern Chile using a combined on-/offshore network
Accurate hypocentre determination in the seismogenic zone of the subducting Nazca Plate in northern Chile using a combined on-/offshore network
复制标题
DOI：
10.1046/j.1365-246x.1999.00893.x
复制
发表时间：
1999-09-01
影响因子：
2.8
通讯作者：
Asch, G
中科院分区：
文献类型：
--
作者：
Husen, S;Kissling, E;Asch, G
俯冲带的耦合板块界面--通常称为孕震区--被认为是致命地震的起源。利用1995年7月30日安托法加斯塔逆冲型地震（M-w = 8.0）余震序列的一个子集研究了智利北方孕震区的范围。为了实现可靠和精确的震源位置，我们采用了最小的1-D模型的概念，其中包括迭代的速度和震源参数的同时反演。最小的1-D模型是由车站校正，这是由近地表速度的不均匀性和个别站海拔的影响。通过重新定位矿山爆炸，这是不包括在反演中，我们得到的绝对定位误差为1公里的震中和2公里的震源深度。分辨率参数ALE和DSPR的研究证明了海上台站对海上事件定位精度的重要性。根据精确确定的震源，我们计算出的深度为46公里的下限的孕震区，这是在很好的协议与以前的研究，这一地区。对于上限，我们发现深度为20公里。我们的结果之间的上限的孕震区和表面的一个asepersion区与其他研究提出的剥离带;该结果也与安托法加斯塔弧前区的热研究。
The coupled plate interface of subduction zones-commonly called the seismogenic zone-has been recognized as the origin of fatal earthquakes. A subset of the aftershock series of the great Antofagasta thrust-type event (1995 July 30; M-w = 8.0) has been used to study the extent of the seismogenic zone in northern Chile. To achieve reliable and precise hypocentre locations we applied the concept of the minimum 1-D model, which incorporates iterative simultaneous inversion of velocity and hypocentre parameters. The minimum 1-D model is complemented by station corrections which are influenced by near-surface velocity heterogeneity and by the individual station elevations. By relocating mine blasts, which were not included in the inversion, we obtain absolute location errors of 1 km in epicentre and 2 km in focal depth. A study of the resolution parameters ALE and DSPR documents the importance of offshore stations on location accuracy for offshore events. Based on precisely determined hypocentres we calculate a depth of 46 km for the lower limit of the seismogenic zone, which is in good agreement with previous studies for this area. For the upper limit we found a depth of 20 km. Our results of an aseismic zone between the upper limit of the seismogenic zone and the surface correlates with a detachment zone proposed by other studies; the results are also in agreement with thermal studies for the Antofagasta forearc region.