FN Archimer Export Format PT J TI Melting features along the western Ryukyu slab edge (northeast Taiwan): Tomographic evidence - art. no. B12402 BT AF LIN, Jing-Yi HSU, SK SIBUET, Jean-Claude AS 1:;2:;3:; FF 1:PDG-DOP-DCB-GM-LGG;2:;3:PDG-DOP-DCB-GM-LGG; C1 IFREMER, Ctr Brest, F-29280 Plouzane, France. Natl Cent Univ, Inst Geophys, Chungli 32054, Taiwan. C2 IFREMER, FRANCE UNIV NATL CENT NCU, TAIWAN SI BREST SE PDG-DOP-DCB-GM-LGG IN WOS Ifremer jusqu'en 2018 copubli-int-hors-europe IF 2.839 TC 92 UR https://archimer.ifremer.fr/doc/00000/10898/7751.pdf LA English DT Article DE ;Ryukyu slab;Okinawa Trough;seismic tomography;melting features AB [1] Behind the sedimentary Ryukyu arc lies the Okinawa Trough, whose termination is located at the tip of the Ilan plain ( northern Taiwan), just above the Ryukyu slab edge. The present-day active volcanic front is located 80 - 100 km above the Ryukyu slab and extends from Japan to Kueishantao Island, an islet situated 10 km offshore the Ilan plain. Between December 1990 and May 1999, 3370 earthquakes recorded in northern Taiwan by 65 seismic land stations were used to determine the three-dimensional V-p and V-s velocity structures and V-p/V-s ratios. A low V-s but high V-p/V-s sausage-like body, similar to 30 km in diameter, lies within the Eurasian mantle wedge, on top of the western Ryukyu slab extremity, at depths ranging between 20 and 100 km. We suggest that the H2O-rich component formed by dehydration processes from subducting sediments, oceanic crust, and serpentinized mantle above the Ryukyu slab and along the vertical portion of the slab edge might explain the presence of the sausage-like body. A low V-s but high V-p/V-s channel rises obliquely from the sausage-like body at a depth of 40 km in direction of the andesitic Kueishantao Island. We propose that the H2O-rich component and/or melt rise up from the sausage-like body and interfere with the Okinawa Trough back arc basin magmas formed in the upper mantle/lower crust. Then magmas propagate upward within the upper brittle crust through veins and/or narrow conduits. PY 2004 PD DEC SO Journal Of Geophysical Research Solid Earth SN 0148-0227 PU Amer Geophysical Union VL 109 IS B12 UT 000225586600006 DI 10.1029/2004JB003260 ID 10898 ER EF