The shallow velocity structure across the Dead Sea Transform fault, Arava Valley, from seismic data
The shallow velocity structure across the Dead Sea Transform fault, Arava Valley, from seismic data
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地震数据显示的横跨阿拉瓦谷死海转换断层的浅层速度结构
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发表时间：
2007
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通讯作者：
Y. Bartov
中科院分区：
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作者：
T. Ryberg;M. Weber;Z. Garfunkel;Y. Bartov
[1] 将层析反演技术应用于折射 P 波的初至走时，以研究阿拉瓦断层 (AF) 附近的地壳最浅部分、死海与红海之间的死海转换 (DST) 段；层析成像反演技术被应用于折射 P 波的初至走时。一条 100 公里长的地震线以 AF 为中心并大致垂直于 AF。手动拾取来自可控震源和爆炸弹的大量 P 波走时（>280,000）并用于反演浅层 P 波速度结构。正则化反演方法（Zelt 和 Barton，1998）用于走时的层析反演。对模型和反演参数进行了广泛的测试，以得出可靠的纵波速度模型。补充棋盘测试表明，根据速度均匀性的大小，速度结构可以很好地解析到几公里的深度。该模型代表了 DST 系统整个宽度上的第一个浅 P 波速度，显示了与地表地质以及一些埋藏结构密切相关的特征。该模型进一步表明，AF 垂直向下延伸至少 3 公里。观察到的上地壳速度的变化意味着存在与大的横向断层偏移相容的简单变形。根据该模型，提出了 DST 系统的结构和动态解释。通过整合众所周知的地表地质和附近的钻孔，成功地对几个其他主要断层和与 DST 相关的浅沉积盆地的深度延伸和几何形状进行了成像。这项工作再次证实了 DST 是一个典型的转换断层系统，其主要走滑运动局限于狭窄的区域。
[1] Tomographic inversion techniques were applied to first-arrival traveltimes of refracted P waves to study the shallowest part of the crust in the vicinity of the Arava Fault (AF), the Dead Sea Transform (DST) segment between the Dead Sea and the Red Sea; tomographic inversion techniques were applied to first-arrival traveltimes of refracted P waves. A 100-km-long seismic line was centered on and oriented approximately perpendicular to the AF. A large number of P wave traveltimes from vibroseis and explosive shots (>280,000) were picked manually and used to invert for shallow P wave velocity structure. The regularized inversion approach (Zelt and Barton, 1998) was used for the tomographic inversion of the traveltimes. Extensive testing of model and inversion parameters was carried out to derive a reliable P wave velocity model. Complementary checker-board tests indicate that depending on the size of velocity homogeneities, the velocity structure is well resolved down to a depth of several kilometers. This model represents the first shallow P wave velocity across the whole width of the DST system, showing features that correlate well with surface geology and also some buried structures. The model further suggests that the AF extends vertically downward to at least 3 km. The observed variation in upper-crustal velocity implies the existence of a simple deformation compatible with a large lateral fault offset. From this model, a structural and dynamic interpretation of the DST system is then presented. The depth extension and geometry of several additional major faults and DST-associated shallow sedimentary basins were successfully imaged through the integration of the well-known surface geology and nearby boreholes. This work again confirms the DST as a typical transform fault system with a dominant strike-slip motion confined to a narrow zone.