Non-volcanic seismic swarm and fluid transportation driven by subduction of the Philippine Sea slab beneath the Kii Peninsula, Japan
加藤 愛太郎*; 雑賀 敦; 武田 哲也*; 岩崎 貴哉*; 松澤 暢*
Kato, Aitaro*; Saiga, Atsushi; Takeda, Tetsuya*; Iwasaki, Takaya*; Matsuzawa, Toru*
To understand the mechanism of an intensive non-volcanic seismic swarm in the Kii Peninsula, Japan, we used a dense seismic linear array to measure fine-scale variations of seismic velocities and converted teleseismic waves. A low-velocity anomaly confined to just beneath the seismic swarm area is clearly imaged, which spatially correlates with an uplifted surface area, and a highly conductive and strong attenuative body. These results suggest that fluids such as partial melt or water are present beneath this non-volcanic seismic swarm area. It is notable that the island arc Moho below the seismic swarm area is at depths of ca. 32 km in the northern part of the seismic swarm area, and shallows to ca. 20 km towards the south, due to an upwardly raised structure of serpentinized mantle wedge. In addition, we show that hydrated oceanic crust of the subducting Philippine Sea slab is characterized by low-velocities with a high Poisson's ratio at depths shallower than 40 km. Water released from the subducting oceanic crust could cause serpentinization of the mantle wedge and infiltration into the forearc base of the overlying plate. The interaction between dehydration of the subducting oceanic crust and hydration of the mantle wedge and overlying plate exerts an important role in driving the non-volcanic seismic swarm activity in the Kii Peninsula.
使用言語 : English
掲載資料名 : Earth, Planets and Space (Internet)
: 66
ページ数 : p.86_1 - 86_8
発行年月 : 2014/08
出版社名 : Springer
特許データ :
論文URL :
キーワード : non-volcanic seismic swarm; fluid; dehydration of oceanic crust; serpentinized mantle wedge
使用施設 :
広報プレスリリース :
受委託・共同研究相手機関 :
登録番号 : AA20140301
抄録集掲載番号 : 42001057
論文投稿番号 : 14701
Accesses  (From Jun. 2, 2014)
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