High-resolution imaging of the North Anatolian Fault Zone in the broader Marmara region from near-fault seismic recordings

根据近断层地震记录对更广泛的马尔马拉地区北安纳托利亚断层带进行高分辨率成像

• 批准号: 341428181
• 负责人: Professor Dr. Marco Bohnhoff
• 金额: --
• 依托单位: Institute of Geophysics
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/341428181?language=en
• 关键词: resolution; imaging; North; Anatolian; Fault

The North Anatolian Fault Zone (NAFZ) is the most active plate-bounding strike-slip fault in Europe and has produced numerous large devastating earthquakes in historic times. A series of large earthquakes starting in 1912 has activated the entire 1200km-long fault zone except for the Marmara section that is located in direct vicinity to the 15-million population center of Istanbul and currently overdue for a M>7 event.We aim at imaging the horizontal and vertical structures, identify and investigate bimaterial interfaces and low-velocity damage at the NAFZ in NW Turkey using Fault Zone Head Waves along with trapped and reflected waves, direct body waves and near-fault anisotropy. The results will substantially contribute to an improved seismic hazard assessment for this key region based on refined determination of the relevant fault-zone structure and physics along the NAFZ. We will also apply a recently introduced passive imaging technique that allows making use of converted phases and their inversion together with synthetic waveforms. Our study will focus on three key sections of the NAFZ in the Marmara region, (1) the Princes Island segment below the eastern Sea of Marmara where the ICDP-driven GONAF observatory has recently been implemented, (2) the Ganos fault further to the west that last ruptured in a M7.4 earthquake in 1912, and (3) the combined Izmit-Düzce rupture that produced two consecutive M>7 earthquakes in 1999. We will make use of extensively seismic waveform recordings that are either already available (Princes Islands segment, Izmit-Düzce) or will be acquired in the frame of a scheduled field campaign (Ganos).The high-resolution fault-zone images to be obtained in the here proposed study are expected to contribute to fundamental aspects of earthquake and fault dynamics on the NAFZ, including the mode and propagation direction of earthquake ruptures, triggering and effective constitutive laws. In particular the results will also provide a detailed characterization and subsequent seismic hazard for the easternmost portion of the Marmara section of the NAFZ that is expected to produce a major (M>7) earthquake in the near future.

北安那托利亚断裂带（NAFZ）是欧洲最活跃的板块边界走滑断裂带，在历史上曾发生过许多毁灭性的大地震。从1912年开始的一系列大地震已经激活了整个1200公里长的断裂带，但马尔马拉部分除外。马尔马拉部分位于紧邻1500万人口的伊斯坦布尔中心，目前早该发生1870年的地震。我们的目标是利用断裂带头波、捕获波和反射波、直接体波和近断层各向异性，对土耳其西北部NAFZ的水平和垂直结构进行成像，识别和研究双材料界面和低速损伤。基于对NAFZ相关断裂带结构和物理特性的精确确定，研究结果将大大有助于改进这一关键地区的地震危险性评估。我们还将应用最近引入的被动成像技术，该技术可以利用转换相位及其反演以及合成波形。我们的研究将集中在马尔马拉地区NAFZ的三个关键部分，(1)马尔马拉海东部下方的王子岛段，最近在那里实施了icdp驱动的GONAF观测站，(2)再往西的加诺斯断层，上一次在1912年发生7.4级地震时破裂，(3)1999年连续两次发生M bbbb7级地震的izmitt - d<s:1> zce断裂。我们将广泛利用现有的地震波形记录（王子群岛段，izmitt - d<e:1> zce）或将在预定的现场活动框架内获得的地震波形记录（Ganos）。本研究获得的高分辨率断裂带图像有望为NAFZ上地震和断层动力学的基本方面做出贡献，包括地震破裂的模式和传播方向、触发和有效本构律。特别是，这些结果还将提供NAFZ马尔马拉段最东端的详细特征和随后的地震危险，预计在不久的将来会发生一次大地震（mbb70）。