Quake Characteristics near Canada's Coasts

加拿大海岸附近的地震特征

• 批准号: RGPIN-2019-04297
• 负责人: Zhang, Miao
• 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: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=683590
• 关键词: Quake; Characteristics; near; Canada; Coasts

Ninety percent of earthquakes (EQs) that affect Canadians happen near Canada's coasts and it is crucial to characterize these EQs from coast to coast. A large majority of these EQs occur offshore, indicating potential for tsunamis that directly threaten the coastal population of Canada. Due to the lack of broadband ocean bottom seismometers (BBOBS) in Canada so far, very limited knowledge about any of these EQs has been accumulated. For the next 5 years, I propose to study the characteristics of Canada's coastal quakes (e.g., EQs and landslides) using state-of-the-art methods and unprecedented seismic data recorded by the new BBOBS from the National Facility for Seismic Imaging (NFSI) housed at Dalhousie University. I will focus on the Queen Charlotte Fault (QCF) offshore the west coast of Canada and the western Baffin Bay offshore northeastern Canada. ******The QCF is located between the Pacific and North American tectonic plates offshore western Canada and southeast Alaska and sustains high deformation rate (>50 mm/yr). The mechanisms of strain accommodation and primary controls on brittle failure during EQ ruptures along this margin remain unknown due to the lack of modern geophysical data and advanced methods. I will take part in a comprehensive Canada-US seismic survey scheduled for 2020-2021 along ~450 km segment of the QCF that encompasses systematic variations in plate boundary obliquity. Sixty-two BBOBS will be deployed for 15 months. Small EQs will be detected and located using methods that I have developed. We will develop a state-of-the-art focal mechanism inversion method to determine relative source parameters of small EQs. Our EQs locations and focal mechanisms are anticipated to reveal spatial variations in the detailed seismic structure and deformation mechanism of the plate boundary.******Baffin Bay is situated in a zone of high EQ risk. On June 17, 2017, one of the tallest (100 m-high wave) tsunamis in recorded history devastated the remote settlement of Nuugaatsiaq in western Greenland, directly across Baffin Bay from Nunavut, Canada. I will participate in a multidisciplinary Canadian investigation of the western Baffin Bay. Using machine learning techniques, we will develop a start-of-the-art system for seismicity detection and classification using data from 30 BBOBS to be deployed in the western Baffin Bay during 2020-2021. Integrated with the results of the planned geological and archeological work, we will provide a detailed geohazard map for the study area summarizing the threat from landslides, EQs, and tsunamis. ******Source characterization is fundamental but challenging in seismology, which is especially true for focal mechanism inversion of quakes and their classification. My proposed research not only conducts scientific observation but also provides geohazard prediction. I anticipate that our results will be used by multiple organizations such as NRCan, DRDC and local governments, ultimately to the benefit of many Canadians.

90%影响加拿大人的地震(EQ)发生在加拿大海岸附近，从东海岸到西海岸描述这些EQ是至关重要的。这些EQ中的绝大多数发生在近海，表明可能发生直接威胁加拿大沿海人口的海啸。由于到目前为止，加拿大还没有宽带海底地震仪(BBOB)，人们对其中任何一个方程的了解都非常有限。在接下来的5年里，我建议使用最先进的方法和由达尔豪西大学国家地震成像设施(NFSI)新的BBOBS记录的前所未有的地震数据来研究加拿大沿海地震的特征(例如，EQ和山体滑坡)。我将重点介绍加拿大西海岸的夏洛特女王断层(QCF)和加拿大东北部的巴芬湾西部。*QCF位于太平洋和北美板块之间，位于加拿大西部和阿拉斯加东南部近海，保持着高变形速率(&gt；50毫米/年)。由于缺乏现代地球物理数据和先进的方法，该边缘EQ破裂过程中的应变调节机制和脆性破坏的主要控制机制尚不清楚。我将参加计划于2020-2021年沿着QCF约450公里段进行的加拿大-美国综合地震调查，该调查涵盖了板块边界倾角的系统变化。62个BBOB将部署15个月。将使用我开发的方法来检测和定位小均衡器。我们将开发一种最先进的震源机制反演方法来确定小等量子数的相对源参数。我们的EQ位置和震源机制预计将揭示板块边界详细的地震结构和变形机制的空间变化。*巴芬湾位于EQ风险较高的区域。2017年6月17日，有记录以来最高(100米高)的海啸之一摧毁了格陵兰西部的偏远定居点Nuugaatsiaq，该定居点与加拿大努纳武特直接隔着巴芬湾。我将参与加拿大对西部巴芬湾的多学科调查。利用机器学习技术，我们将开发一个先进的地震活动检测和分类系统，使用来自30个BBOB的数据，将于2020-2021年部署在巴芬湾西部。结合已规划的地质和考古工作成果，我们将为研究区提供详细的地质灾害图，总结滑坡、EQ和海啸的威胁。震源描述在地震学中是基本的，但也是具有挑战性的，对于地震的震源机制反演及其分类尤其如此。我提出的研究不仅可以进行科学观测，还可以提供地质灾害预测。我预计，我们的成果将被NRCan、DRDC和地方政府等多个组织使用，最终造福于许多加拿大人。