Detection of missing triggered slow events toward understanding physical characteristics of the plate interface
| Project/Area Number |
16K05537
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Solid earth and planetary physics
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| Research Institution | Kyoto University |
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Principal Investigator |
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| Project Period (FY) |
2016-04-01 – 2020-03-31
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| Project Status |
Completed (Fiscal Year 2019)
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| Budget Amount *help |
¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000)
Fiscal Year 2018: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2017: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2016: ¥2,990,000 (Direct Cost: ¥2,300,000、Indirect Cost: ¥690,000)
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| Keywords | 超低周波地震 / 動的誘発 / ベイズ推定 / 粒子フィルタ / 2016年紀伊半島沖（三重県沖）の地震 / 低周波地震 / 2017年チアパス地震 / 粒子フィルタ・スムーザ / 粒子スムーザー / 地震波干渉法 / 低周波微動 / 表面波 / 誘発 / スロー地震 / 誘発作用 |
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| Outline of Final Research Achievements |
Remote triggering of very low-frequency (VLF) earthquakes in the Nankai subduction zone by surface waves from a moderate to large, distant earthquake was examined using a new approach. The triggering of another type of tectonic slow earthquake/tremor and slow slip was previously discovered using simple signal processing techniques. A Bayesian technique was developed to detect seismic signals and estimate the maximum likelihood source parameters of VLF earthquakes that might have been remotely triggered. This approach was applied to seismograms of the 2016 Mw 5.9 off-Kii Peninsula earthquake, recorded in western Shikoku. Six VLF earthquakes with magnitudes from 3.4 to 4.3 likely occurred in the seismogenic regions of ambient low-frequency earthquakes/tremors (LFEs), and were likely triggered by the arrivals of high-amplitude surface waves. These VLF earthquakes were more sensitive to stress changes than LEEs. This is the first reported example of dynamic triggering of VLF earthquakes.
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| Academic Significance and Societal Importance of the Research Achievements |
沈み込み帯で発生するスローイベントのうち、超低周波地震だけが動的誘発されていることが見つかっていなかった。本研究により、超低周波地震も他のスローイベントと同様に動的に直接誘発される事が確認され、プレートの沈み込み帯におけるプレート境界の特徴についての理解が進み、巨大地震発生に掛かるメカニズムの解明に貢献すると考えられる。
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Report
(5 results)
Research Products
(8 results)
