Identifying potentially active faults in mainland British Columbia using available datasets

使用可用数据集识别不列颠哥伦比亚省大陆潜在的活动断层

• 批准号: RGPIN-2021-03031
• 负责人: Hobbs, Tiegan
• 金额: $ 1.82万
• 依托单位: University of British Columbia
• 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=751299
• 关键词: Identifying; potentially; active; faults; mainland

Many developed countries consider shallow, crustal faults in their hazard assessments, where there is evidence that faults are either active or capable. In British Columbia (BC), however, only one such crustal fault has been included in our national seismic hazard model to date. Treating the southwest BC mainland as if devoid of shallow, crustal faults is at odds with both our tectonic understanding of how subduction zone stresses are imparted to the upper crust, and the neighbouring United States (US) Geological Survey assessment which includes numerous faults extending at least to the border and presumably further north. Thus, the threat of active faults, and their secondary hazards, in the densely populated Lower Mainland region remains largely unknown. Currently, I lead the development of the National Seismic Risk Model Scenario Earthquake Catalogue (release in November 2020). This work requires knowledge of faults across Canada as well as an understanding of how those faults impact the built environment and communities. Now, we hope to extend this work to as-yet unmapped faults. We propose to use existing data to hunt for possibly active faults in the southern Coast Mountain region extending from the Strait of Georgia East to Manning Park, and from the Canada/US border North to the Pemberton Icefields - a region home to approximately 2.8 million people and assets valuing roughly 41% of Canada's gross domestic product. This research program will improve our understanding of crustal faults on the mainland by: [1] using recently collected digital elevation data to visually identify potentially active faults based on their geomorphic expression, [2] modelling their potential stress accumulation using a newly developed tectonic block model, [3] quantitatively assessing the potential physical impacts and socioeconomic consequences of ruptures using seismic risk assessment, [4] going into the field to document geologic evidence of recent displacement along prospective faults, such as volcanic dike offsets, and [5] using geodetic and other geophysical data to characterize the current deformation and activity rate of faults. Through the Earthquake Scenario Catalogue, a Fault Database we will create, and RiskProfiler.ca - a user-friendly web platform - citizens, scientists, city planners, and policy makers will be able to freely access the evidence they need to enact risk reduction strategies. We hope to `finish drawing' faults which currently only exist on the US side of the border, and identify faults which are well-suited to more detailed and expensive studies through paleoseismic trenching, campaign Global Navigation Satellite System (GNSS) with helicopter access, or high resolution Light Detection and Ranging (LiDAR). This program will contribute to the scientific community by allowing a young, female PI to train 2 new scientists, to be selected from groups currently under-represented in geosciences.

许多发达国家在其灾害评估中考虑浅层地壳断层，因为有证据表明断层是活动的或有能力活动的。然而，在不列颠哥伦比亚省（BC），迄今为止，只有一个这样的地壳断层被列入我们的国家地震危险性模型。将西南BC大陆视为没有浅层地壳断层，这与我们对俯冲带应力如何传递到上地壳的构造理解以及邻近的美国地质调查局的评估不一致，美国地质调查局的评估包括许多断层至少延伸到边界，并可能进一步向北延伸。因此，在人口稠密的低陆平原地区，活动断层及其次生灾害的威胁在很大程度上仍然是未知的。目前，我领导了国家地震风险模型情景地震目录（2020年11月发布）的开发。这项工作需要了解加拿大各地的断层，以及了解这些断层如何影响建筑环境和社区。现在，我们希望将这项工作扩展到尚未映射的断层。我们建议使用现有的数据来寻找可能在南部海岸山脉地区从格鲁吉亚海峡向东延伸到曼宁公园，并从加拿大/美国边境向北延伸到彭伯顿冰原-一个拥有约280万人口和资产的地区，价值约为加拿大国内生产总值的41%。这项研究计划将通过以下方式提高我们对大陆地壳断层的认识：[1]使用最近收集的数字高程数据，根据地貌表达直观地识别潜在的活动断层，[2]使用新开发的构造块体模型对其潜在的应力积累进行建模，[3]使用地震风险评估定量评估断裂的潜在物理影响和社会经济后果，[4]进入现场记录最近沿预期断层沿着位移的地质证据，如火山岩脉偏移，[5]使用大地测量和其他地球物理数据来表征断层的当前变形和活动速率。通过地震情景目录，我们将创建一个断层数据库，以及RiskProfiler.ca-一个用户友好的网络平台-公民，科学家，城市规划者和政策制定者将能够自由访问他们制定风险降低战略所需的证据。我们希望“完成绘制”目前只存在于美国一侧的断层，并通过古地震挖沟、配备直升机的全球导航卫星系统（GNSS）或高分辨率光探测和测距（LiDAR）来确定非常适合进行更详细和昂贵研究的断层。该计划将通过允许一名年轻的女性PI培训2名新的科学家来为科学界做出贡献，这些科学家将从目前在地球科学领域代表性不足的群体中选出。