Wide-angle seismic profiling of arc-arc collision zone in the northern Izu-Ogasawara arc –KY0408 cruise–

抄録

We carried out a deep wide-angle seismic experiment using a large airgun array and total 103 ocean bottom seismographs (OBSs) in the northern Izu-Ogasawara arc area, which was conducted by R/V Kaiyo of Japan Agency for Marine-Earth Science and Technology (JAMSTEC) from July 8, 2004 to July 22 (KY04-08 cruise). Objectives of this cruise are to know a velocity structure of the arc-arc collision zone and to understand relationship between the crustal growth and the arc collision, which is one of important parameters to clarify nature of the oceanic arc growth. An airgun-OBS seismic line was set from western Sagami Bay near granitic Izu peninsula to Tori-shima along the direction of the volcanic front. We shot a large airgun array with total volume 12,000 cu. in. and recorded the seismic signals on OBSs with four components and a hydrophone streamer. In this paper, we summarize information of the seismic experiments and introduce OBS data and reflection data.