The scientific party of Ocean Drilling Program (ODP) Leg 195 would like to thank all those who gave invaluable help and support to make the drilling expedition and observatory installations in the western Pacific Ocean an outstanding success. We are particularly grateful to the crew of the JOIDES Resolution, under the supervision of Captain Tom Hardy and Drilling Superintendent Wayne Malone, and Laboratory Officer Roy Davis and his staff of marine technicians for their hard work.

The operations of Leg 195 were carefully planned and conducted with the expert guidance of ODP Operations Manager Mike Storms and Operations Engineer Derryl Schroeder. Their expertise and advice contributed enormously to the success of challenging instrument emplacement and coring operations in three very difficult settings: the throat of an active serpentinite mud volcano in the Mariana forearc, in extremely deep water in the middle of the Philippine Sea, and in very strong currents just hours out of port.

Site survey data were critical for a successful drilling operation in the Mariana forearc area. These data are based on the results of two expeditions with the research vessels Thomas Thompson and Moana Wave. The site survey cruises were supported by the National Science Foudation and a site augmentation grant from the United States Science Support Program. We are particularly indebted to the Oregon State University coring facility for its superb support in the cheerful person of Chris Moser, to Bruce Appelgate and the Hawaii Mapping Research Group personnel for their expert assistance in the mapping efforts, and to Greg Moore for supervision of the seismic data collection, processing, and interpretation.

We thank the Earthquake Research Institute, the University of Tokyo, the Deep Sea Research Department, and the Japan Marine Science and Technology Center for their support. The borehole seismometer installation is partly supported by the Ocean Hemisphere Network Project from the Ministry of Education, Culture, Sports, Science, and Technology of Japan and is conducted as part of the International Ocean Network project.

The Leg 195 science party expresses its gratitude to the JOIDES planning structure and all governmental and academic institutions that provided the financial and logistical support to plan and conduct this remarkable expedition. Finally, we appreciate the skills and cheerful cooperation of the ODP Publication Services staff in preparing this volume.