scholarly journals A Possible Roll-Over Slab Geometry Under the Caroline Plate Imaged by Monte Carlo Finite-Frequency Traveltime Inversion of Teleseismic SS Phases

2021 ◽  
Vol 9 ◽  
Author(s):  
Nobuaki Fuji ◽  
Hyoihn Jang ◽  
Atsushi Nakao ◽  
YoungHee Kim ◽  
David Fernández-Blanco ◽  
...  
Keyword(s):  
Velocity Structure ◽  
Seismic Velocity ◽  
Three Dimensional ◽  
Pacific Plate ◽  
Slab Geometry ◽  
Seismic Velocity Structure ◽  
The Pacific ◽  
Two Factors ◽  
End Members ◽  
Roll Back

The shape of a subducting slab varies as a function of trench motion. Two end-members of subduction modes are geodynamically possible: roll-back mode underneath neighboring plates and roll-over mode underneath the plate itself. Whereas most of major slabs seem to roll back while the Pacific plate shows a slab piling behavior down to ∼1,000 km depth under the Mariana trench, no clear evidence of slab roll-over in nature has been reported so far. Here we show a possible roll-over slab beneath the Caroline microplate, revealed from its three-dimensional seismic velocity structure derived by analyzing teleseismic reverberating SS phases. We suggest that slab roll-over is driven by at least two factors: 1) the overall buoyancy and fragility of the Caroline microplate at the surface, induced by a thin hot mantle plume that rises from depths ≥800 km; and 2) the pushing force of the Pacific plate acting on the trailing edge of the Caroline plate.

scholarly journals Three-dimensional seismic velocity structure of Mauna Loa and Kilauea volcanoes in Hawaii from local seismic tomography

2014 ◽  
Vol 119 (5) ◽  
pp. 4377-4392 ◽  
Author(s):  
Guoqing Lin ◽  
Peter M. Shearer ◽  
Robin S. Matoza ◽  
Paul G. Okubo ◽  
Falk Amelung
Keyword(s):  
Seismic Tomography ◽  
Velocity Structure ◽  
Seismic Velocity ◽  
Three Dimensional ◽  
Seismic Velocity Structure ◽  
Mauna Loa

scholarly journals Three‐dimensional seismic velocity structure in the Sichuan basin, China

2016 ◽  
Vol 121 (2) ◽  
pp. 1007-1022 ◽  
Author(s):  
Maomao Wang ◽  
Judith Hubbard ◽  
Andreas Plesch ◽  
John H. Shaw ◽  
Lining Wang
Keyword(s):  
Sichuan Basin ◽  
Velocity Structure ◽  
Seismic Velocity ◽  
Three Dimensional ◽  
Seismic Velocity Structure ◽  
The Sichuan Basin

Three-Dimensional Seismic Velocity Structure Beneath Japanese Islands and Surroundings Based on NIED Seismic Networks Using both Inland and Offshore Events

2017 ◽  
Vol 12 (5) ◽  
pp. 844-857 ◽  
Author(s):  
Makoto Matsubara ◽  
Hiroshi Sato ◽  
Kenji Uehira ◽  
Masashi Mochizuki ◽  
Toshihiko Kanazawa ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Sea Of Japan ◽  
Velocity Structure ◽  
Seismic Velocity ◽  
The Sea Of Japan ◽  
Seismic Velocity Structure ◽  
The Pacific ◽  
The Pacific Ocean ◽  
Seismic Networks ◽  
Japanese Islands

Tomographic analysis of the seismic velocity structure beneath oceans has always been difficult because offshore events determined by onshore seismic networks have large uncertainties in depth. In order to use reliable event locations for our computations, we have developed a method to use the hypocentral depths determined by the NIED F-net with moment tensor solutions using long-period (20-50 s) waves from offshore events away from onshore seismic networks. We applied seismic tomographic method to events occurring between the years 2000 and 2015 to generate a tomographic image of the Japanese Islands and the surrounding using travel time data picked by the NIED Hi-net, hypocenteral information for onshore earthquakes from the Hi-net, and hypocenter information for offshore events from the F-net. The seismic velocity structure at depths of 30-50 km beneath the Pacific Ocean off the east coast of northeastern Japan and onshore Japan was clearly imaged using both onshore and offshore event date. The boundary between high and low P-wave velocities (Vp) is clearly seen at the Median Tectonic Line beneath southwestern Japan at depths of 10 and 20 km. We discuss how the high-Vp lower crust and low-Vp upper crust beneath central Japan and towards the Sea of Japan are responsible for the failed rift structures formed during the opening of the Sea of Japan. Due to consequent shortening, the crustal deformation has been concentrated along the failed rift zone. Resolution of shallow structures beneath the ocean is investigated using S-net data, confirming the possibility of imaging depths of 5-20 km. In future studies, application of S-net data will be useful in evaluating whether the failed rift structure, formed during the late Cretaceous to early Tertiary, continues towards the shallow regions beneath the Pacific Ocean.

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