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，历史上曾发生过多次特大破坏性地震。 1912 年开始的一系列大地震激活了整个 1200 公里长的断裂带，但马尔马拉断层除外，马尔马拉断层紧邻伊斯坦布尔 1500 万人口中心，目前早该发生 M>7 级地震。我们的目标是使用断层带头波和困波对土耳其西北部 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。 以及反射波、直接体波和近断层各向异性。基于对 NAFZ 沿线相关断层带结构和物理特性的精确确定，这些结果将极大地有助于改进该关键区域的地震危险性评估。我们还将应用最近推出的无源成像技术，该技术允许利用转换后的相位及其反转以及合成波形。我们的研究将重点关注马尔马拉地区 NAFZ 的三个关键部分，(1) 马尔马拉海东部以下的王子岛部分，ICDP 驱动的 GONAF 观测站最近在那里建成，(2) 更靠西的加诺斯断层，最后一次在 1912 年的 M7.4 地震中破裂，以及 (3) 产生了两次连续 M>7 地震的伊兹米特-迪兹杰联合破裂 我们将利用广泛的地震波形记录，这些记录要么已经可用（王子群岛部分，伊兹米特-迪兹杰），要么将在预定的现场活动框架内获取（Ganos）。这里提出的研究中获得的高分辨率断层带图像预计将有助于 NAFZ 地震和断层动力学的基本方面，包括地震的模式和传播方向。 地震破裂、触发和有效本构规律。特别是，结果还将提供 NAFZ 马尔马拉部分最东部部分的详细特征和随后的地震危险性，预计该部分将在不久的将来产生大地震（M>7）。