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タイトル: | Dynamic Earthquake Triggering in Southern California in High Resolution: Intensity, Time Decay, and Regional Variability |
著者: | Miyazawa, Masatoshi https://orcid.org/0000-0002-3319-1216 (unconfirmed) Brodsky, Emily E. Guo, Huiyun |
著者名の別形: | 宮澤, 理稔 |
キーワード: | aftershock equivalent magnitude delayed triggering dynamic triggering triggering intensity |
発行日: | Jun-2021 |
出版者: | American Geophysical Union (AGU) |
誌名: | AGU Advances |
巻: | 2 |
号: | 2 |
論文番号: | e2020AV000309 |
抄録: | Earthquake triggering by seismic waves has been recognized as a phenomenon for nearly 30 years. However, our ability to study dynamic triggering has been limited by our ability to capture the triggering stresses accurately and record the resultant earthquakes. Here we use full waveforms from a dense seismic network and a modern, high‐resolution seismic catalog to measure triggering in Southern California from 2008 to 2017 based on interevent time ratios. We find that the fractional seismicity rate change, which we term triggering intensity or triggerability, as a function of peak strain change for the period of ∼20 s due to distant earthquakes is monotonically increasing and compatible with earlier measurements made with a disjoint data set from 1984 to 2008. A triggering strain of 1 microstrain is equivalent to the local productivity generated by an M1.8 earthquakes. This result implies that a prediction of seismicity rate changes can be made based on recorded ground shaking using the same formalism as currently used for aftershock prediction. For a teleseismic event, this small level of triggering occurs throughout the region and thus aggregates to a regional effect. We find that the triggering rate decays after the triggerer follows an Omori‐Utsu law, but at a much slower rate than a typical aftershock sequence. The slow decay rate suggests that an ancillary process such as creep or fluid flow must be part of dynamic triggering. The prevalence of triggering in areas of creep or fluid involvement reinforces this inference. A triggering cascade of secondary earthquakes is insufficient to explain the data. |
記述: | 遠地地震によって誘発される地震活動の特徴を解明 --地震ビッグデータ解析を通じて--. 京都大学プレスリリース. 2021-05-06. |
著作権等: | © 2021. The Authors. This is an open access article under the terms of the Creative Commons Attribution 4.0 International Public License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. |
URI: | http://hdl.handle.net/2433/262768 |
DOI(出版社版): | 10.1029/2020AV000309 |
関連リンク: | https://www.kyoto-u.ac.jp/ja/research-news/2021-05-06 |
出現コレクション: | 学術雑誌掲載論文等 |
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