Elucidating the Mechanics of Tsunami Generating Earthquake Rupture with Long Period Seismology

用长周期地震学阐明海啸引发地震破裂的机制

• 批准号: 1850831
• 负责人: Miaki Ishii
• 金额: $ 29.06万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-05-01 至 2021-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1850831&HistoricalAwards=false
• 关键词: Elucidating; Mechanics; Tsunami; Generating; Earthquake

Submarine earthquakes are capable of generating uncharacteristically large tsunamis, and drastically increase the hazard facing most of the world's population, which currently lives along the coastlines. Current techniques used to study submarine earthquakes are expensive and cannot be applied to most earthquakes of interest. The lack of observations has hindered the understanding of whether an earthquake will displace the seafloor and increase the likelihood of generating a significant tsunami. The theory developed in this project will provide a new fundamental tool for the study of submarine earthquakes with significant scientific and societal implications. A new framework will be developed that overcomes previous theoretical limitations and allows us to develop an easily utilized, inexpensive tool which will allow for the detection of slip on the seafloor from distant recordings of ground motion alone. This tool will then be used to examine giant earthquakes in the last 15 years that produced devastating tsunamis, as well as recent moderate-size earthquakes from around the world. By studying a large number of earthquakes with the newly developed tool, a better understanding will be obtained of why some earthquakes displace the seafloor while others do not. This project could provide an improvement for tsunami hazard assessment. The project supports the training of a postdoctoral investigator.The first component of this project will establish the theoretical and observational framework required to distinguish events for which slip reached and did not reach the surface. This theory will provide a simple seismological diagnostic tool, and has the added benefit of complementing numerical models, seafloor instrumentation, drilling, or marine surveys. The second component of this project will provide the necessary observations required to determine the physical mechanisms controlling submarine surface rupture by applying the diagnostic to long-period seismic data from a large number of events recorded by the Global Seismographic Network. The new framework will be validated using the large amount of shallow slip that was measured to have occurred during the 2011 Tohoku-Oki Earthquake. To what extent this type of shallow slip is observed in giant megathrust earthquakes, such as the 2010 and 2015 Chile and the 2004 and 2010 Sumatra tsunami earthquakes, as well as recent moderate-size earthquakes will be determined. Using the outcome of the survey of large and moderate-size earthquakes, an attempt will be made to determine the properties of fault zones (e.g., presence of accretionary wedge, subducted sediment thickness, fault dip-angle, etc.) that govern the rupture of the shallowest part of plate boundary.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

海底地震能够产生非特征的海啸，并大大增加了目前居住在海岸线上的世界大部分人口面临的危险。用于研究潜艇地震的当前技术很昂贵，不能应用于大多数感兴趣的地震。缺乏观察结果阻碍了对地震是否会置换海底并增加产生重要海啸的可能性的理解。该项目中开发的理论将为研究具有重大科学和社会意义的海底地震提供新的基本工具。将开发一个新的框架，以克服以前的理论局限性，并使我们能够开发出一种易于使用的，廉价的工具，该工具将允许单独从地面运动的遥远记录中检测到海底上的滑移。 然后，该工具将用于检查过去15年中巨大的地震，这些地震产生了毁灭性的海啸，以及最近来自世界各地的中等大小的地震。通过使用新开发的工具研究大量地震，可以更好地理解为什么有些地震置换了海底，而另一些地震则没有。 该项目可以改善海啸危害评估。 该项目支持博士后研究者的培训。该项目的第一个组成部分将建立理论和观察框架，以区分该事件的到达且未达到表面的事件。该理论将提供一个简单的地震诊断工具，并具有补充数值模型，海底仪器，钻探或海洋调查的额外好处。该项目的第二个组成部分将提供必要的观察结果，以确定控制海底表面破裂的物理机制，通过将诊断施加到全球地震学网络记录的大量事件中的长周期地震数据中。新框架将使用在2011年Tohoku-Oki地震期间进行的大量浅层滑动进行验证。在巨大的大型地震中观察到这种浅层滑移在多大程度上，例如2010年和2015年智利以及2004年和2010年苏门答腊海啸地震，以及最近的中等大小地震。利用对大型和中等大小的地震的调查的结果，将尝试确定断层区域的特性（例如，存在积聚楔，俯冲楔，俯冲的沉积物厚度，倾角倾角等），以控制板界的浅薄部分。该奖项反映了NSF的Infortional of Suthorial of STURD的范围，这是由NSF的构建范围进行了评估，并且是由NSF的构建范围进行了评估。影响审查标准。