Geophysical studies of plate boundary zone processes in western North America and lithospheric structure of terrestrial planets

北美西部板块边界带过程和类地行星岩石圈结构的地球物理研究

• 批准号: 418288-2012
• 负责人: Audet, Pascal
• 金额: $ 2.26万
• 依托单位: University of Ottawa
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=634085
• 关键词: Geophysical; studies; plate; boundary; zone

Over the next five years my research program will focus on two key problems in geophysics, one in observational seismology and the other in the rheology of the lithosphere on Earth and terrestrial planets. The first project concerns the structure of the crust and mantle around major plate boundary zones and faults in western North America, from the San Andreas Fault in California to the northern Canadian Cordillera in the Yukon and Northwest Territories, and their influence on earthquake and crustal deformation. A number of different styles of earthquake, each with its own significance for seismic hazard, occur along major fault lines in this region. In addition to large destructive earthquakes (like the 1906 San Adreas earthquake or the 2011 Tohoku-Oki earthquake in Japan), these faults harbor a wide variety of slip modes, including the recently discovered "slow slip" and associated "non-volcanic tremors". Although not a direct threat, there is growing evidence that these slow slip earthquakes are associated with regular earthquake occurrence through structural properties (e.g., fluids) of the fault, as imaged using seismological data. This research aims to clarify the role played by such structural attributes in the faulting and earthquakes processes.The second project addresses a long-standing problem in solid-Earth geophysics, namely the global rheology and strength of the lithosphere of the Earth and terrestrial planets. The solid Earth's response to geological loads (e.g., ice sheets, river deltas) is determined by its rigidity, or long-term strength, which is obtained by comparing the Earth's gravitational field anomalies with the topography. Knowledge of lithospheric strength is a useful parameter to understand crustal evolution and heat transport in the Earth and planets. Following major revisions of models and techniques used to estimate this parameter, this research will focus on the application of the new methods to Earth and other terrestrial planets (e.g., Mars, Venus, Mercury) to establish a classification of planetary rheology for the inner solar system.

在接下来的五年里，我的研究计划将集中在地球物理学的两个关键问题上，一个是观测地震学，另一个是地球和类地行星岩石圈的流变学。第一个项目涉及北美西部主要板块边界带和断层周围的地壳和地幔结构，从加州的圣安德烈亚斯断层到育空地区和西北地区的北方加拿大科迪勒拉，及其对地震和地壳变形的影响。许多不同类型的地震，每一种都有其自身的地震危险性，发生在该地区的沿着主要断层线上。除了大的破坏性地震（如1906年的圣阿德里亚斯地震或2011年的日本东北冲地震），这些断层还具有各种各样的滑动模式，包括最近发现的“缓慢滑动”和相关的“非火山震颤”。虽然不是直接威胁，但越来越多的证据表明，这些缓慢滑动的地震通过结构特性（例如，流体）的断层，如使用地震数据成像。本研究旨在阐明这种结构属性在断层和地震过程中所起的作用。第二个项目解决固体地球物理学中一个长期存在的问题，即地球和类地行星岩石圈的全球流变学和强度。固体地球对地质载荷的响应（例如，冰盖、河流三角洲）是由其刚性或长期强度决定的，这是通过将地球重力场异常与地形进行比较而获得的。岩石圈强度是了解地球和行星地壳演化和热输运的一个有用参数。在对用于估计这一参数的模型和技术进行重大修订之后，这项研究将侧重于将新方法应用于地球和其他类地行星（例如，火星，金星，水星），以建立一个分类的行星流变学的内太阳系。