FN Archimer Export Format PT J TI Spatial variations in the frequency-magnitude distribution of earthquakes in the southwestern Okinawa Trough BT AF LIN, Jing-Yi SIBUET, Jean-Claude LEE, Chao-Shing HSU, Shu-Kun KLINGELHOEFER, Frauke AS 1:1,4;2:1;3:2;4:3;5:1; FF 1:PDG-DOP-DCB-GM-LGG;2:PDG-DOP-DCB-GM-LGG;3:;4:;5:PDG-DOP-DCB-GM-LGG; C1 IFREMER, Ctr Brest, F-29280 Plouzane, France. Natl Taiwan Ocean Univ, Inst Appl Geophys, Chilung 202, Taiwan. Natl Cent Univ, Inst Geophys, Chungli 32001, Taiwan. Coll France, Chaire Geodynam, F-13545 Aix En Provence 4, France. C2 IFREMER, FRANCE UNIV NATL TAIWAN OCEAN NTOU, TAIWAN UNIV NATL CENT NCU, TAIWAN COLL FRANCE, FRANCE SI BREST SE PDG-DOP-DCB-GM-LGG IN WOS Ifremer jusqu'en 2018 copubli-france copubli-int-hors-europe IF 1.188 TC 10 UR https://archimer.ifremer.fr/doc/2007/publication-3036.pdf LA English DT Article DE ;Magma chamber;Slab tear;Southern Okinawa Trough backarc basin;B Values AB The relations between the frequency of occurrence and the magnitude of earthquakes are established in the southern Okinawa Trough for 2823 relocated earthquakes recorded during a passive ocean bottom seismometer experiment. Three high b-values areas are identified: (1) for an area offshore of the Ilan Plain, south of the andesitic Kueishantao Island from a depth of 50 km to the surface, thereby confirming the subduction component of the island andesites; (2) for a body lying along the 123.3 degrees E meridian at depths ranging from 0 to 50 km that may reflect the high temperature inflow rising up from a slab tear; (3) for a third cylindrical body about 15 km in diameter beneath the Cross Backarc Volcanic Trail, at depths ranging from 0 to 15 km. This anomaly might be related to the presence of a magma chamber at the base of the crust already evidenced by tomographic and geochemical results. The high b-values are generally linked to magmatic and geothermal activities, although most of the seismicity is linked to normal faulting processes in the southern Okinawa Trough. PY 2007 PD MAY SO Earth, Planets and Space SN 1343-8832 PU TERRAPUB VL 59 IS 4 UT 000247321500005 BP 221 EP 225 ID 3036 ER EF