The Marmara region in Turkey is an important geological setting, both from a tectonic and a seismic hazard/risk perspective. We present a new map of crustal thickness variation across this complex region to better understand the interplay of past and present tectonic processes that have formed present‐day structure. Maps of crustal thickness are created using Ps converted phases and receiver function (RF) analysis of earthquakes recorded at all publicly available seismic stations and stations in the national monitoring network (run by AFAD Disaster and Emergency Management Authority Turkey). RFs are converted from time to depth using a local 3‐D full‐waveform tomographic model and are combined in multiphase common conversion point stacks. Direct P to S converted arrivals and associated multiples are mapped to produce continuous maps of the Moho discontinuity. Results show Moho depths ranging from 26–41 km with a regional trend of westward thinning reflecting the effects of the extensional regime in western Anatolia and the neighboring Aegean Sea. The thinnest crust is observed beneath the western end of the Sea of Marmara, attributed to transtensional basin opening. A distinct region of increased crustal thickness bounded by the West Black Sea Fault in the west, and the northern strand of the North Anatolian Fault in the south, defines the ancient crustal terrane of the Istanbul Zone. Isostatic arguments indicate that the thickened crust and lower elevation in the Istanbul Zone require it to be underlain by thicker lithosphere, a conclusion that is consistent with its hypothesized origin near the Odessa shelf.

中文翻译：

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土耳其西北部马尔马拉地区海沿岸的地壳厚度变化：现代和古代构造过程的反映

从构造和地震灾害/风险角度看，土耳其的马尔马拉地区都是重要的地质环境。我们提供了这个复杂区域内地壳厚度变化的新地图，以更好地了解形成当今结构的过去和现在的构造过程之间的相互作用。地壳厚度图是使用Ps转换的相位和接收器功能（RF）分析创建的，该分析在所有公开可用的地震台站和国家监测网络中的地震台站中记录（由AFAD灾难和紧急情况管理局土耳其管理）。使用本地3D全波形层析成像模型将RF从时间转换为深度，并组合在多相公共转换点堆栈中。直接P到S映射转换后的到达和关联的倍数以生成Moho不连续性的连续图。结果表明，莫霍面深度在26-41 km之间，并有向西变薄的区域趋势，反映了安那托利亚西部和邻近的爱琴海的扩张体制的影响。在马尔马拉海西端下方观察到最薄的地壳，这归因于张拉盆地的开放。地壳厚度增加的一个明显区域由西部的西黑海断层和南部的北安纳托利亚断层的北段界定，定义了伊斯坦布尔地区的古代地壳。等静压论证表明，伊斯坦布尔地区的地壳增厚和海拔较低，要求它被较厚的岩石圈所覆盖，