Abstract The Qeshm earthquake with magnitude Mw 6.0 occurred on November 27, 2005, on a southern island in Iran and was followed by many aftershocks. We analyzed the aftershock waveforms and the first arrival traveltimes to calculate the 3D velocity model. The tomographic procedure was conducted in three different depth ranges from the subsurface to a depth of 17 km beneath Qeshm Island. The subsurface was probed by the Rayleigh wave tomographic method. The waveforms were filtered in the period range of 0.6 to 6 s, the dispersion curves were calculated for the selected signals, and a 2D tomography procedure was then performed. The resulting group dispersion measurement maps were inverted to obtain the shear wave velocity model to a depth of 5 km. However, the first arrival traveltimes were applied to obtain the VP and VP/VS models using the SIMULPS program in the depth range of 5 to 14 km, while depths ranging from 14 to 17 km were considered by the event interferometric approach. All appropriate interevent empirical Green's functions (EGFs) were extracted in the 4 different slices/depths, and the Rayleigh wave tomography processing was then repeated for these layers at the period of 1.2 s. Our results demonstrate that analysis of the interevent EGFs can yield useful information from depths for which a velocity model cannot be obtained via classic techniques. In addition to the Qeshm Fault, which appears as a stretched low-velocity anomaly, the Hormuz salt and evaporites may be other sources with low velocity. Although finding a direct relation between faulting and folding and/or any other mechanism of folding is difficult on Qeshm Island, the role of the Hormuz salt in generating them is undeniable. The rise of the Hormuz salt and evaporites, which appear as a low-velocity (weak) zone, can directly affect crustal layering (lower sedimentary cover and basement), fault dip and anticline formation and deformation at depths to 14 km. According to the effect of these tectonic features, folding and secondary faults, the soft sedimentary thickness varies between 2 and 3 km.

中文翻译：

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来自表面波、初至和干涉干涉测量断层扫描方法的格什姆岛（SE Zagros）下的高分辨率上地壳速度结构

摘要 2005 年 11 月 27 日，伊朗南部岛屿格什姆发生 6.0 级地震，随后发生多次余震。我们分析了余震波形和初至走时来计算 3D 速度模型。断层扫描程序在三个不同的深度范围内进行，从地下到格什姆岛下方 17 公里的深度。通过瑞利波层析成像方法探测地下。在 0.6 到 6 s 的周期范围内对波形进行滤波，计算所选信号的色散曲线，然后执行 2D 断层扫描程序。将得到的组色散测量图倒置以获得 5 公里深度的剪切波速度模型。然而，使用 SIMULPS 程序在 5 到 14 公里的深度范围内应用初到走时来获得 VP 和 VP/VS 模型，而事件干涉法考虑了 14 到 17 公里的深度。在 4 个不同的切片/深度中提取所有适当的事件间经验格林函数 (EGF)，然后以 1.2 秒的周期对这些层重复瑞利波断层扫描处理。我们的结果表明，对事件间 EGF 的分析可以从无法通过经典技术获得速度模型的深度产生有用的信息。除了表现为拉长的低速异常的格什姆断层外，霍尔木兹盐和蒸发岩可能是其他低速源。尽管在格什姆岛上很难找到断层和折叠和/或任何其他折叠机制之间的直接关系，但不可否认霍尔木兹盐在生成它们中的作用。霍尔木兹盐分和蒸发岩的上升表现为低速（弱）带，可直接影响地壳分层（下层沉积盖层和基底）、断层倾角和背斜形成以及深度达 14 公里的变形。根据这些构造特征、褶皱和次生断层的影响，软沉积厚度在 2 至 3 公里之间。断层倾角和背斜形成和变形深度达 14 公里。根据这些构造特征、褶皱和次生断层的影响，软沉积厚度在 2 至 3 公里之间。断层倾角和背斜形成和变形深度达 14 公里。根据这些构造特征、褶皱和次生断层的影响，软沉积厚度在 2 至 3 公里之间。