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Journal: |
Journal of Geophysical Research 2019 No.7
clicks:223 |
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Title:
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Author:
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B. Gardonio1 , M. Campillo2 , D. Marsan3 , A. Lecointre2, M. Bouchon2 , and J. Letort2,4 |
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Adress: |
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Abstract:
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The observation of a transient slip 1 month before the rupture of the 2011 Tohoku
earthquake is a conandrum since the area was supposedly fully coupled. A better understanding of the
mechanisms at work during the preseismic phase is thus fundamental. However, the configuration of the
Pacific plate and the location of the Tohoku rupture zone 200 km from the coast make it difficult to detect
microseismic events. In this study, we use a multidimensional template matching (MDTM) technique to
detect earthquakes that are hidden in the noise. The temporal distribution of these 395 newly detected
earthquakes provides new insights on the slip history of the megathrust earthquake epicentral zone. The
detected events can be separated into two groups: 187 low-frequency detections (below 5 Hz) that well
recorded the episodes of earthquake migration prior to the Tohoku earthquake and 208 high-frequency
detections (above 10 Hz) that occurred close to the rupture zones of the M ≥ 4.8–6 earthquakes that struck
between the 9 March 2011 M7.3 foreshock and the 30 November 2010 Tohoku-Oki earthquake. The
seismic rate of these high frequency detection events starts to increase on 30 November 2010 until the
Tohoku earthquake. |
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Comment: |
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