Processed multichannel seismic data across the Mariana island-arc system, acquired during the R/V Maurice Ewing survey EW0203 (2002)

The MARGINS programs in the US and Japan (of NSF and MEXT) funded an integrated seismic study (marine multi-channel seismic reflection, controlled-source wideangle reflection/refraction, and passive recording of local and teleseismic earthquakes) to provide a comprehensive velocity, attenuation, structural and stratigraphic image of the Mariana island-arc system, from the subducting Pacific Plate to the backarc, at 14-20N, 141-149E. The study included two cruises, EW0202 and EW0203. This cruise, EW0203, served as part 2 of the study, deploying Ocean Bottom Seismographs (OBSs) and shooting MCS lines over them. Its companion cruise, EW0202, concentrated on MCS profiling. The principal objectives of the study were to understand: 1) velocity and attenuation structure of the mantle, 2) large-scale flow of the mantle wedge, 3) velocity structure of the subducting oceanic crust, 4) seismic stratigraphy and structure of the forearc, arc and remnant arc, 5) the magma chamber below the volcanoes, 6) a possible double seismic zone, and 7) updip an downdip limits of the seismogenic zone. Funded by NSF grants OCE00-01798, OCE00-01956, OCE00-01938, OCE00-02878.