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: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=714763
• 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.

影响加拿大人的90%的地震（EQ）发生在加拿大海岸附近，从海岸到海岸描述这些EQ至关重要。大部分这些EQ发生在近海，表明海啸的潜在可能性直接威胁到加拿大的沿海人口。由于缺乏宽带海底地震仪（BBOBS）在加拿大迄今为止，非常有限的知识，这些EQ已经积累。在接下来的5年里，我建议研究加拿大沿海地震的特征（例如，EQs和滑坡）使用最先进的方法和前所未有的地震数据记录的新BBOBS从国家设施的地震成像（NFSI）设在达尔豪西大学。我将重点介绍加拿大西海岸近海的夏洛特女王断层（QCF）和加拿大东北部近海的巴芬湾西部。 QCF位于太平洋和北美构造板块之间，加拿大西部近海和阿拉斯加东南部，并维持高变形速率（>50毫米/年）。由于缺乏现代地球物理资料和先进的方法，EQ断裂沿着该边缘的应变调节机制和脆性破坏的主要控制因素仍然未知。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，该调查包括板块边界相似性的系统变化。62个BBOBS将部署15个月。小EQ将被检测和定位使用的方法，我已经开发。我们将发展一种最先进的震源机制反演方法来确定小EQs的相对震源参数。我们的EQs位置和震源机制有望揭示板块边界详细地震结构和变形机制的空间变化。 巴芬湾位于高情商风险区。2017年6月17日，有史以来最高（100米高）的海啸摧毁了格陵兰西部的Nuugaatsiaq偏远定居点，直接穿过加拿大努纳武特的巴芬湾。我将参加加拿大对巴芬湾西部的多学科调查。利用机器学习技术，我们将开发一个最先进的地震活动性检测和分类系统，使用2020-2021年期间在巴芬湾西部部署的30个BBOBS的数据。结合计划的地质和考古工作的结果，我们将提供一个详细的地质灾害地图的研究区域总结滑坡，地震和海啸的威胁。 震源特征是地震学中的一个基本问题，但也是一个挑战，尤其是对于地震的震源机制反演和分类。我所提出的研究不仅进行科学观测，而且提供地质灾害预测。我预计，我们的研究结果将被NRCan、DRDC和地方政府等多个组织使用，最终使许多加拿大人受益。