Collaborative Research: Capitalizing on EarthScope Transportable Array Data to Better Characterize Induced Seismic Sequences

合作研究：利用 EarthScope 可移动阵列数据更好地表征诱发地震序列

• 批准号: 1460232
• 负责人: Deborah Kilb
• 金额: $ 24.4万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-04-15 至 2020-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1460232&HistoricalAwards=false
• 关键词: Collaborative; Research; Capitalizing; EarthScope; Transportable

The increase in the number of felt and damaging earthquakes near injection sites in Middle America has the public's attention. Given this, there is an ever-growing need to better understand how these sequences develop and to educate the public about the science of induced seismicity. The problem is that the low station density in the central and eastern United States means that many small earthquakes are not easily identified using standard analyst review techniques, and the lack of a complete catalog of small earthquakes greatly impedes induced seismicity studies. Additionally, while temporary networks are often deployed after a sequence has started producing significant or felt earthquakes, these networks miss the initiation of the induced earthquake sequence. Our solution is to use data from the EarthScope Transportable Array, to establish more complete catalogs that better describe the full characteristics (both before and after) of induced seismic sequences. To obtain a better understanding of the source physics of induced seismicity, we propose to systematically identify currently uncataloged small magnitude earthquakes located near fluid injection sites in the central and eastern US by applying a newly developed frequency domain detection algorithm and array visualization mapping techniques to transportable array data. Using newly detected events, we will build a template waveform catalog for use as subspace detectors. The detections will be used to build more complete catalogs for eight geographically dispersed basins. These enhanced catalogs will be analyzed to address the following questions: (1) Are there detectable events in basins where other catalogs show no seismicity or are some basins aseismic? (2) To what extent are the template events we identify similar in waveform characteristics and/or location to previously cataloged events? (3) Are observed rate increases consistent with the Gutenberg-Richter relation and is there a predictable change in b-value with time? (4) Do transient stresses from the passage of relatively large surface waves dynamically trigger additional induced events or otherwise change the distribution of induced seismicity? This study will more fully develop frequency domain detection algorithms and subspace detectors tuned to identify small earthquakes, and will be used to create new earthquake catalogs with magnitude of completeness levels lower (magnitude less than 2.4) than most existing catalogs. This large spatial scale analysis has the potential to provide new information about induced earthquakes and provide a quantitative measure of the ubiquity of induced seismicity in different regions.

中美洲注入点附近有感地震和破坏性地震数量的增加引起了公众的关注。鉴于此，越来越需要更好地了解这些序列如何发展并教育公众有关诱发地震活动的科学知识。问题在于，美国中部和东部的台站密度较低，这意味着使用标准分析审查技术不容易识别许多小地震，而且缺乏完整的小地震目录极大地阻碍了诱发地震活动性研究。此外，虽然通常在序列开始产生强烈地震或有感地震后部署临时网络，但这些网络会错过诱发地震序列的启动。我们的解决方案是使用来自 EarthScope 可移动阵列的数据来建立更完整的目录，以更好地描述诱发地震序列的完整特征（之前和之后）。为了更好地了解诱发地震活动的震源物理，我们建议通过应用新开发的频域检测算法和阵列可视化映射技术来系统地识别位于美国中部和东部流体注入地点附近的目前未编目的小震级地震。数组数据。使用新检测到的事件，我们将构建一个模板波形目录以用作子空间检测器。这些探测结果将用于为八个地理上分散的盆地建立更完整的目录。这些增强型目录将被分析以解决以下问题：（1）在其他目录显示无地震活动的盆地中是否存在可探测到的事件，或者某些盆地是否发生地震？ (2) 我们识别的模板事件在波形特征和/或位置方面与先前编目事件的相似程度如何？ (3) 观察到的速率增加是否与 Gutenberg-Richter 关系一致，b 值随时间的变化是否存在可预测的变化？ (4) 相对较大的表面波通过时产生的瞬态应力是否会动态触发额外的诱发事件或以其他方式改变诱发地震活动的分布？这项研究将更全面地开发频域检测算法和子空间探测器，用于识别小地震，并将用于创建新的地震目录，其完整性级别低于大多数现有目录（震级小于 2.4）。这种大空间尺度分析有可能提供有关诱发地震的新信息，并提供不同地区诱发地震活动普遍性的定量测量。