Understanding the deformation and processes that link ductile flow in the deep continental crust with frictional processes in the upper crustal seismogenic zone

了解将深部大陆地壳中的延性流与上地壳地震带中的摩擦过程联系起来的变形和过程

• 批准号: RGPIN-2020-05658
• 负责人: Grujic, Djordje
• 金额: $ 2.19万
• 依托单位: Dalhousie University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=750946
• 关键词: Understanding; deformation; processes; link; ductile

Subduction zones-regions of Earth's crust where one tectonic plate dives beneath another-are usually but not always associated with frequent, violent earthquakes. Occasionally, the downgoing plate slides slowly, smoothly and almost silently under the overriding plate. Canadian scientists have contributed to the research of seismic slow signals with geophysical observations of the Cascadia subduction zone. However, field observations, rock experiments and theoretical developments are also needed to advance our understanding of these newly identified fault slip phenomena. The proposed research program, with implications for future earthquakes offshore western Canada, aims to (a) expand our knowledge of mechanical processes that link mega earthquakes in the upper crust to steady and continuous slip in the lower crust via the brittle-ductile transition zone, which hosts the seismic slow signals, and (b) test a set of innovative methods to determine the ages of pre-instrumental earthquakes. (a) The importance of this research lies in the potential relationship between the fault transition zone and the parts of faults that generate destructive earthquakes. Some calculations find that the probability of a large earthquake occurring during a slow-slip event is 30-100 times greater than background probabilities. My research program involves interdisciplinary studies of exemplary exposed megathrust systems that record different stages of their development. Continental megathrust systems will be investigated via integration of observations across a range of scales and approaches, including field studies, microanalyses, thermochronology, geochronology, and numerical modelling. (b) Deformation data obtained from faulted rocks should be interpreted in the context of temporal or spatial variations in seismic processes. Thus, precise and accurate dating is crucial and entails developing innovative techniques that directly link age data to evidence of seismic slip in the rock record. This goal is achievable because of recent developments in our understanding of the physics of signals from minerals released via exposure to heat produced by seismic slip, and improvements in related analytical methods. To test the new techniques, we selected several locations where a surface earthquake rupture of known age provides access to samples suitable for attaining this goal. In addition to taking a leadership role in the discipline, Canada will benefit from this research by further understanding the processes responsible for Earth's major evolutionary steps, which can then feed into policy development for geohazard and environmental protection. Program goals will involve Canadian and international collaborators and train 2 PhD and 2 MSc graduate students, 1 PDF and undergraduates who will become knowledgeable in science communication and international and earthquake research, collaborate with world-leading research groups and gain access to world-class infrastructure.

地壳的俯冲区域 - 一个构造板在另一个构造板上俯冲在另一个层，但并不总是与频繁的，暴力的地震相关。有时，下板在覆盖板下方缓慢，平稳，几乎默默地滑动。加拿大科学家对Cascadia俯冲带的地震慢速信号进行了研究。但是，还需要进行现场观察，岩石实验和理论发展，以促进我们对这些新确定的断层滑移现象的理解。拟议的研究计划对加拿大西部的未来地震产生了影响，旨在（a）扩大我们对机械过程的了解，这些过程将上皮中的巨型地震连接到通过脆弱的延性过渡区中的下层地壳中的稳定而连续的滑移，它具有地震慢信号，以及（b）测试一组创新方法，以确定乐队前地震的年龄。 （a）这项研究的重要性在于断层过渡区与产生破坏性地震的部分之间的潜在关系。一些计算发现，在慢滑行事件中发生大地震的概率比背景概率大30-100倍。我的研究计划涉及跨学科研究，对记录其发展的不同阶段的模范暴露的巨型系统。将通过整合一系列尺度和方法的观测值，包括现场研究，微分析，热量体学，地质学学和数值建模，对大陆大陆系统进行研究。 （b）从断层岩石获得的变形数据应在地震过程中的时间或空间变化的背景下进行解释。因此，精确和准确的约会至关重要，需要开发创新的技术，这些技术将年龄数据直接连接到岩石记录中地震滑移的证据。这一目标是可以实现的，因为我们对通过暴露于地震滑移产生的热量以及相​​关分析方法的改善而对矿物质信号物理的理解的最新发展进行了实现。为了测试新技术，我们选择了几个位置，其中已知年龄的表面地震破裂提供了适用于实现此目标的样品的访问。除了在该学科中发挥领导作用外，加拿大还将通过进一步理解负责地球主要进化步骤的过程来从这项研究中受益，然后可以为地球扎华和环境保护提供政策制定。计划目标将涉及加拿大和国际合作者，并培训2位博士学位和2名MSC研究生，1名PDF和本科生，他们将在科学传播和国际和地震研究中知识渊博，与世界领先的研究小组合作，并获得世界一流的基础设施。 。