Tectonic implications of carbonate deposits on the eastern slope of the Hahajima Seamount in the collision zone between the Izu–Bonin Arc on the Philippine Sea Plate and the Ogasawara Plateau on the Pacific Plate

&#160;Although far from the Japanese main island of Honshu, the Izu-Bonin area is a very active seismic zone. It experienced two major earthquakes in the past decade: (i) the 2010 Mw 7.4 Ogasawara Islands intraplate earthquake that occurred on the 2010/12/22 in a normal-fault, in the outer-rise of the trench of the Pacific plate that subduct underneath the Philippine Sea plate, (ii) the Mw 7.9 Bonin island very-deep focus earthquake that occurred on the 2015/05/30 that was preceded by an acceleration of the seismicity at large depth. The aftershocks of the outer-rise earthquake were distributed in a NW-SE belt and formed subparallel lines along a fracture zone in the Pacific plate. The aftershocks were first located in the surroundings of the main shock rupture and migrated over the following days beyond or into the Ogasawara Plateau and the Uyeda Ridge. Due to its location in the sea and with only a few GPS and seismic stations around, it is difficult to assess the extent of the post-seismic deformation of this earthquake.In that context, the analysis of repeating earthquakes as a proxy for slip on the fault is very useful. Using ten seismic stations, we detected 130 repeating earthquakes. Their number inscreased in the next few days following the main shock and are located in the northern branch of the fault. Ten days later, another increase of repeating earthquakes occurs on the subduction interface concomitent with a displacement to the east seen by GPS stations, indicating that the outer-rise earthquake might have triggered a slow slip event on the subduction interface. The main shock was also followed by an extremely rapid migration of the seismicity at depths up to 80km showing that it perturbed the entire outer-rise structure of the slab at depth.

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Paleomagnetism of the Joban Seamount Chain: Its origin and tectonic implications for the Pacific plate

Journal of Geophysical Research Atmospheres ◽

10.1029/96jb03624 ◽

1997 ◽

Vol 102 (B3) ◽

pp. 5145-5155 ◽

Cited By ~ 3

Author(s):

Desiderius C. P. Masalu ◽

Kensaku Tamaki ◽

William W. Sager

Keyword(s):

Pacific Plate ◽

Tectonic Implications ◽

The Pacific ◽

Seamount Chain

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Configuration and structure of the Philippine Sea Plate off Boso, Japan: constraints on the shallow subduction kinematics, seismicity, and slow slip events

Earth Planets and Space ◽

10.1186/s40623-019-1090-y ◽

2019 ◽

Vol 71 (1) ◽

Cited By ~ 2

Author(s):

Aki Ito ◽

Takashi Tonegawa ◽

Naoki Uchida ◽

Yojiro Yamamoto ◽

Daisuke Suetsugu ◽

...

Keyword(s):

Receiver Function ◽

Function Analysis ◽

Philippine Sea Plate ◽

Slow Slip ◽

Low Velocity ◽

Slow Slip Events ◽

Philippine Sea ◽

Receiver Function Analysis ◽

Eastern Edge ◽

Upper Boundary

Abstract We applied tomographic inversion and receiver function analysis to seismic data from ocean-bottom seismometers and land-based stations to understand the structure and its relationship with slow slip events off Boso, Japan. First, we delineated the upper boundary of the Philippine Sea Plate based on both the velocity structure and the locations of the low-angle thrust-faulting earthquakes. The upper boundary of the Philippine Sea Plate is distorted upward by a few kilometers between 140.5 and 141.0°E. We also determined the eastern edge of the Philippine Sea Plate based on the delineated upper boundary and the results of the receiver function analysis. The eastern edge has a northwest–southeast trend between the triple junction and 141.6°E, which changes to a north–south trend north of 34.7°N. The change in the subduction direction at 1–3 Ma might have resulted in the inflection of the eastern edge of the subducted Philippine Sea Plate. Second, we compared the subduction zone structure and hypocenter locations and the area of the Boso slow slip events. Most of the low-angle thrust-faulting earthquakes identified in this study occurred outside the areas of recurrent Boso slow slip events, which indicates that the slow slip area and regular low-angle thrust earthquakes are spatially separated in the offshore area. In addition, the slow slip areas are located only at the contact zone between the crustal parts of the North American Plate and the subducting Philippine Sea Plate. The localization of the slow slip events in the crust–crust contact zone off Boso is examined for the first time in this study. Finally, we detected a relatively low-velocity region in the mantle of the Philippine Sea Plate. The low-velocity mantle can be interpreted as serpentinized peridotite, which is also found in the Philippine Sea Plate prior to subduction. The serpentinized peridotite zone remains after the subduction of the Philippine Sea Plate and is likely distributed over a wide area along the subducted slab.

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Small-scale mantle convection system and stress field under the Pacific plate

Physics of The Earth and Planetary Interiors ◽

10.1016/0031-9201(76)90095-9 ◽

1976 ◽

Vol 13 (3) ◽

pp. 212-217 ◽

Cited By ~ 16

Author(s):

Han-Shou Liu ◽

Edward S. Chang ◽

George H. Wyatt

Keyword(s):

Stress Field ◽

Mantle Convection ◽

Pacific Plate ◽

Small Scale ◽

The Pacific

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Contrasting subduction structures within the Philippine Sea plate: Hydrous oceanic crust and anhydrous volcanic arc crust

Geochemistry Geophysics Geosystems ◽

10.1002/2014gc005321 ◽

2014 ◽

Vol 15 (5) ◽

pp. 1977-1990 ◽

Cited By ~ 6

Author(s):

Ryuta Arai ◽

Takaya Iwasaki ◽

Hiroshi Sato ◽

Susumu Abe ◽

Naoshi Hirata

Keyword(s):

Oceanic Crust ◽

Philippine Sea Plate ◽

Volcanic Arc ◽

Philippine Sea

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