Seismotectonics of the Bitlis–Zagros Fold and Thrust Belt in Northern Iraq and Surrounding Regions from Moment Tensor Analysis
Seismotectonics of the Bitlis–Zagros Fold and Thrust Belt in Northern Iraq and Surrounding Regions from Moment Tensor Analysis
复制标题
伊拉克北部及周边地区比特利斯-扎格罗斯褶皱冲断带地震构造的矩张量分析
作者：
Wathiq Abdulnaby;Hanan Mahdi;N. Numan;H. Al
伊拉克北方是阿拉伯板块和欧亚板块之间会聚板块边界的一部分。这两个板块之间的碰撞区表现为Bitlis-Zagros褶皱和冲断带。该带是现今地震活动带中最活跃的地区之一。这项研究旨在提高我们对伊拉克北方及周边地区地震构造活动的认识。为了达到这一目标，我们使用波形矩张量反演方法来确定25个震级≥3.5的地震的震源深度、矩震级、断层面解和主应力轴方向。这些事件的地震数据是从属于坎迪利观测站和地震研究所、地震学联合研究所、欧洲地震观测站和研究设施以及伊拉克地震网的54个宽带台站收集的。使用地震学计算机程序3.30版（Herrmann和Ammon 2004）进行分析。结果表明，这些地震的震源深度一般在15 ~ 25 km之间。断层面解表明，走滑机制是研究区最主要的机制，通常具有反向分量。应力状态显示三个主要方向：南北、东北-西南和东西。这些方向与该地区的构造体制是可比的。
Northern Iraq represents part of the convergent plate boundary between the Arabian and Eurasian plates. The collision zone between these two plates is manifested by the Bitlis–Zagros Fold and Thrust Belt. This belt is one of the most seismically active regions among the present active belts. This study intends to improve our knowledge on the seismotectonic activities in northern Iraq and the surrounding areas. To reach this goal, we used the waveform moment tensor inversion method to determine the focal depths, moment magnitudes, fault plane solutions, and directions of the principal stress axes of 25 events with magnitudes ≥3.5. The seismic data of these events were collected from 54 broadband stations which belong to the Kandilli Observatory and Earthquake Research Institute, the Incorporated Research Institutions for Seismology, the Observatories and Research Facilities for European Seismology, and the Iraqi Seismological Network. Computer Programs in Seismology, version 3.30 (Herrmann and Ammon2004), was used for analysis. The results show that the focal depth of these events ranged from 15 to 25 km in general. The fault plane solutions show that the strike-slip mechanism is the most dominant mechanism in the study area, usually with a reverse component. The stress regime shows three major directions; north–south, northeast-southwest, and east–west. These directions are comparable with the tectonic regime in the region.