The Makran subduction zone has produced M 8+ earthquakes and subsequent tsunamis in historic times, hence indicating high risk for the coastal regions of southern Iran, Pakistan, and neighboring countries. Besides this, the Makran subduction zone is an end-member subduction zone featuring extreme properties, with one of the largest sediment inputs and the widest accretionary wedge on Earth. While surface geology and shallow structure of the offshore wedge have been relatively well studied, primary information on the deeper structure of the onshore part is largely absent. We present three crustal-scale, trench-perpendicular, deep seismic sounding profiles crossing the subaerial part of the accretionary wedge of the western Makran subduction zone in Iran. P-wave travel-time tomography based on a Monte Carlo Markov chain algorithm as well as the migration of automatic line drawings of wide-angle reflections reveal the crustal structure of the wedge and geometry of the subducting oceanic plate at high resolution. The images shed light on the accretionary processes, in particular the generation of continental crust by basal accretion, and provide vital basic information for hazard assessment and tsunami modeling.

中文翻译：

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地壳规模增生复合体的解剖：伊朗西部马克兰俯冲带陆上西部地震测深的见解

马克兰俯冲带在历史时期曾发生过M 8+级地震和随后的海啸，因此表明伊朗南部沿海地区，巴基斯坦和邻国的风险很高。除此之外，Makran俯冲带是具有极端性质的端部俯冲带，具有最大的泥沙输入量和地球上最大的增生楔形物之一。虽然对海上楔形的表层地质和浅层结构已经进行了比较充分的研究，但基本上缺少有关陆上部分较深结构的主要信息。我们提出了三个跨伊朗深部Makran俯冲带增生楔的海底部分的地壳尺度，垂直于沟槽的深地震测剖面。基于蒙特卡洛马尔科夫链算法的P波行进时间层析成像以及广角反射的自动线图的偏移显示了高分辨率的俯冲海洋板块的地壳结构和俯冲海洋板块的几何形状。这些图像揭示了增生过程，尤其是基底增生产生的大陆壳，为灾害评估和海啸建模提供了重要的基本信息。