open access

https://hdl.handle.net/2115/67742

Space geodetic observations of repeating slow slip events beneath the Bonin Islands

英語

Intra-plate processes

2017-09-01

Oxford University Press

Geophysical journal international

210(3)

1494-1502

The Pacific Plate subducts beneath the Philippine Sea Plate along the Izu-Bonin Trench. We investigated crustal movements at the Bonin Islands, using Global Navigation Satellite System and geodetic Very Long Baseline Interferometry data to reveal how the two plates converge in this subduction zone. These islands are located similar to 100 km from the trench, just at the middle between the volcanic arc and the trench, making these islands suitable for detecting signatures of episodic deformation such as slow slip events (SSEs). During 2007-2016, we found five SSEs repeating quasi-periodically with similar displacement patterns. In estimating their fault parameters, we assumed that the fault lies on the prescribed plate boundary, and optimized the size, shape and position of the fault and dislocation vectors. Average fault slip was similar to 5 cm, and the average moment magnitude was similar to 6.9. We also found one SSE occurred in 2008 updip of the repeating SSE in response to an M6 class interplate earthquake. In spite of the frequent occurrence of SSEs, there is no evidence for long-term strain accumulation in the Bonin Islands that may lead to future megathrust earthquakes. Plate convergence in Mariana-type subduction zones may occur, to a large extent, episodically as repeating SSEs.

学術雑誌論文

Version of Record

This article has been accepted for publication in Geophysical Journal International ©: 2017 Deasy Arisa and Kosuke Heki Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

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