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.

北安纳托利亚断裂带(NAFZ)是欧洲最活跃的板块边界走滑断层，在历史上曾发生过多次大地震。1912年开始的一系列大地震激活了整个1200公里长的断裂带，除了马尔马拉段，该段位于伊斯坦布尔1500万人口中心附近，目前M&GT；7事件早该发生。我们的目标是成像水平和垂直结构，利用断裂带头部波以及俘获和反射波、直接体波和近断层的各向异性来识别和调查土耳其西北部NAFZ的双材料界面和低速破坏。这些结果将大大有助于改进对这一关键区域的地震危险性评估，其基础是对北美自由贸易区沿线相关断裂带结构和物理特征的精确确定。我们还将应用最近引入的被动成像技术，该技术允许利用转换后的相位及其反演与合成波形一起使用。我们的研究将集中在马尔马拉地区NAFZ的三个关键部分，(1)马尔马拉东海下方的王子岛部分，最近在那里实施了由ICDP驱动的GONAF观测站，(2)更西边的Ganos断层，该断层最后一次在1912年的7.4级地震中破裂，以及(3)1999年连续两次M&GT；7地震的Izmit-Düzce组合破裂。我们将利用广泛的地震波形记录，这些记录要么是已经可用的(王子群岛段，伊兹米特-杜兹切)，要么是在预定的野外活动(Ganos)框架内获得的。在这里拟议的研究中将获得的高分辨率断裂带图像预计将有助于研究NAFZ上的地震和断层动力学的基本方面，包括地震破裂的模式和传播方向、触发和有效的本构规律。特别是，研究结果还将提供北美自由贸易区马尔马拉地段最东端的详细特征和随后的地震风险，预计该地段将在不久的将来发生一次大地震(M&GT；7)。