Collaborative Research: Earthquake Gates: Linking Earthquake Rupture Length to the Dynamics of Restraining Double Bends on the Altyn Tagh Fault

合作研究：地震之门：将地震破裂长度与阿尔金断层双弯抑制动力学联系起来

• 批准号: 1524743
• 负责人: Benchun Duan
• 金额: $ 16.57万
• 依托单位: Texas A&M University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-01 至 2019-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1524743&HistoricalAwards=false
• 关键词: Collaborative; Research; Earthquake; Gates; Linking

The length of a fault rupture generally controls the magnitude of a large earthquake. Unusually large, rare, and unexpected earthquakes overwhelm mitigation measures and the societal capacity to respond, leading to a cascade of disastrous effects. In order to assess the potential for such rare events, this study calibrates how effectively geometrical complexities of a fault impede earthquake rupture propagation. The project, carried out in close collaboration with Chinese researchers, integrates field observations of fault geometry and slip behavior of the Altyn Tagh fault in China, one of the longest active strike-slip faults on Earth, with numerical rupture simulations to predict the range of potential earthquake sizes along a major intracontinental strike-slip fault. The outcome of this research will be a means to assess the likelihood of rare, unusually large events. The project will advance desired societal outcomes through: (1) full participation of women and underrepresented minorities in STEM; (2) improved well-being of individuals in society through a new understanding of earthquake rupture processes; (3) development of a diverse, globally competitive STEM workforce through training of graduate and undergraduate students; and (4) increased partnerships through a strong international collaboration with Chinese scientists and international research experiences for students. The project is supported by the Tectonics Program and NSF's International Science and Engineering program.The research project will develop and apply techniques to integrate field observations of fault geometry, kinematics, and slip behavior with numerical rupture simulations to predict the range of potential earthquake sizes along the central Altyn Tagh fault over a length (800 km) that well exceeds the longest recorded continental strike-slip earthquake (420-450 km). The central Altyn Tagh fault fault is divided into segments by four restraining double bends (Aksay, Pingding Shan, Akato Tagh, and Sulamu Tagh) that are each hypothesized, based on their geometry, to stop most, but not all earthquake ruptures. Multi-cycle spontaneous dynamic rupture models show that these earthquake gates may be open or closed to a particular direction of rupture propagation depending upon fault geometry and stress conditions inherited from prior earthquakes. Prior research showed that dynamic rupture effects (resulting from seismic wave propagation from the rupture front) and interseismic stress relaxation (off-fault deformation) both contribute to geologically testable patterns of along-strike earthquake slip and cumulative slip-rate gradients. This project will apply these rupture models and geologic tests to the Pingding Shan double restraining bend, which appears to be a relatively nascent structure along the Altyn Tagh fault. A thorough field campaign will collect new slip rate, slip-per-event, fault kinematic, and structural data to constrain a multi-cycle rupture model for the Pingding Shan restraining double bend. Models will be developed that couple all four of the major restraining double bends of the central Altyn Tagh fault, and the ensemble behavior of this geologically-calibrated model system will be investigated to determine the likelihood of rare, exceptionally long earthquake ruptures.

断裂破裂的长度通常控制大地震的大小。异常大，稀有和意外的地震压倒了缓解措施和社会反应能力，导致一系列灾难性影响。为了评估这种罕见事件的潜力，本研究校准了断层的有效几何复杂性阻碍地震破裂的传播。该项目与中国研究人员密切合作，整合了中国阿尔蒂·塔格（Altyn Tagh）故障的故障几何形状和滑移行为的现场观察，这是地球上最长的活性走滑断层之一，并具有数值破裂模拟，以预测的范围沿着主要的肠内滑滑断层沿着潜在的地震大小。这项研究的结果将是评估罕见，异常事件的可能性的一种手段。该项目将通过：（1）妇女和代表性不足的少数群体在STEM中的全面参与； （2）通过对地震破裂过程的新了解，改善了社会中个人的福祉； （3）通过培训研究生和本科生来发展多样化的全球竞争性STEM劳动力； （4）通过与中国科学家的强大国际合作和为学生提供国际研究经验，增加了伙伴关系。该项目得到了构造计划和NSF的国际科学与工程计划的支持。研究项目将开发和应用技术，以将故障几何学，运动学和滑移行为与数值破裂模拟与数值破裂模拟的现场观测相结合，以预测潜在地震范围的范围。远远超过记录最长的大陆滑滑地震（420-450 km）的长度（800 km）的中央Altyn Tagh断层。中央Altyn Tagh断层通过四个限制双弯曲（Aksay，Pingding Shan，Akato Tagh和Sulamu Tagh）分为段，它们根据其几何形状，以停止大多数，但并非全部地震破裂。多周期自发的动态破裂模型表明，这些地震大门可能取决于断裂几何形状和从以前的地震遗传的压力条件，向特定的破裂传播方向开放或封闭。先前的研究表明，动态破裂效应（由破裂前沿的地震波传播产生）和跨界应力松弛（OFFOART变形）都有助于沿刺激性地震滑移和累积滑移率梯度的地质测试模式。该项目将将这些破裂模型和地质测试应用于pingding shan双限制弯曲，这似乎是沿Altyn Tagh断层的相对新生的结构。彻底的现场运动将收集新的滑动速率，每项赛道，故障运动学和结构数据，以限制用于plyding shan限制双弯曲的多周期破裂模型。将开发模型，将对中央Altyn Tagh断层的所有主要限制双弯曲的全部四个双弯曲，并且将研究该地质校准模型系统的整体行为，以确定罕见，异常长的地震破裂的可能性。