title: Trial of multidisciplinary observation at an expandable sub-marine cabled station "off-hatsushima island observatory" in sagami bay, Japan.
abstract: Sagami Bay is an active tectonic area in Japan. In 1993, a real-time deep sea floor observatory was deployed at 1,175 m depth about 7 km off Hatsushima Island, Sagami Bay to monitor seismic activities and other geophysical phenomena. Video cameras monitored biological activities associated with tectonic activities. The observation system was renovated completely in 2000. An ocean bottom electromagnetic meter (OBEM), an ocean bottom differential pressure gauge (DPG) system, and an ocean bottom gravity meter (OBG) were installed January 2005; operations began in February of that year. An earthquake (M5.4) in April 2006, generated a submarine landslide that reached the Hatsushima Observatory, moving some sensors. The video camera took movies of mudflows; OBEM and other sensors detected distinctive changes occurring with the mudflow. Although the DPG and OBG were recovered in January 2008, the OBEM continues to obtain data.
authors.affiliation: Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15, Natsushima-cho, Yokosuka, Kanagawa, 237-0061, Japan; E-Mails:  mitsuzawak@jamstec.go.jp  (K.M.);  tgoto@tansa.kumst.kyoto-u.ac.jp  (T.G.);  iwaser@jamstec.go.jp  (R.I.);  araki@jamstec.go.jp  (E.A.);  asakawa@jamstec.go.jp  (K.A.).
authors.forename: Takafumi
authors.initials: T
authors.lastname: Kasaya
authors.forename: Kyohiko
authors.initials: K
authors.lastname: Mitsuzawa
authors.forename: Tada-Nori
authors.initials: TN
authors.lastname: Goto
authors.forename: Ryoichi
authors.initials: R
authors.lastname: Iwase
authors.forename: Keizo
authors.initials: K
authors.lastname: Sayanagi
authors.forename: Eiichiro
authors.initials: E
authors.lastname: Araki
authors.forename: Kenichi
authors.initials: K
authors.lastname: Asakawa
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Mikada
authors.forename: Tomoki
authors.initials: T
authors.lastname: Watanabe
authors.forename: Ichiro
authors.initials: I
authors.lastname: Takahashi
authors.forename: Toshiyasu
authors.initials: T
authors.lastname: Nagao