Plattform Platform	Reise-Nr. Cruise-No.	Zeitraum Period	Projekt Project	Arbeitsgebiet Working area
Sonne1	SO222	08.06.2012 - 19.07.2012		Japan Sea

Fahrtleiter Chief Scientist	Institut Institute	Auslaufhafen Port of departure	Einlaufhafen Port of return	Stationskarte Station map	Schiffsroute Trackchart
Kopf Achim	Universitat Bremen, Zentrum fur Marine Umweltwissenschaften	Hong Kong	Pusan

Ziel der Reise / Objectives of Cruise:

Abstract Approximately 90% of the seismic moment on Earth is released in often devastating subduction zone earthquakes (EQs). In the Integrated Ocean Drilling Program (IODP), the study of seismogenesis along an active convergent margin plays a key role in the form of a multi-expedition effort named "NanTroSEIZE" (Nankai Trough Seismogenic Zone Experiment). To date, eight expeditions (IODP Expeditions 314-316, 319, 322, 326, 332-333) drilled 12 sites along a transect from the incoming plate across the frontal accretionary prism to the forearc basin. Two holes are currently equippe dwith long-term instruments (C0002, C0010). The project Sonne SO222 MEMO, MeBo drilling & in situ long-term Monitoring offshore Japan (Nankai Trough Accretionary Prism), aims to extend the long-term monitoring efforts to active mud volcanoes in the northern Kumano Basin. These features carry gas hydrates and deep-seated fluids, most likely tapping into the seismogenic zone at a depth of several km below seafloor, and are also overlying an area of high strains and a locked plate boundary-thrust. Cruise SO222 sampled both mud volcanoes and background sediments and installed long-term monitoring devices in key locations. The main results of the two legs SO222A and SO222B include: - The discovery of 5 new, previously not reported mud volcanoes, so that there are 13 MVs in the Kumano Basin now; - Gas hydrate presence in many of the features; - Enigmatic pore fluid signatures with high B, Li and Sr, but low Mg in the pore waters, suggesting deep-seated fluid origin; - Successful installation of of 4 MeBo borehole observatories in a total of six holes drilled in appx. 2 km water depth; - Successful installation of six CAT flowmeters on the most active mud volcanoes in the Kumano field; - Successful operation on so-called MeBoCORK observatories with ROV Quest; - Recovery of gravity and MeBo cores as well as TV grab that contain a suite of clasts in the mud breccias that span the range from soft to hard rocks and cover all grain size classes of sedimentary rocks, but also comprise magmatic materials and deformed rocks; - Gas composition attests a biogenic origin for the majority of the mud domes visited; - Heat flow data attest active flow in at least some of the mud domes; however, - No active venting was neither observed by acoustic techniques nor by direct observation with ROV or TV-grab.

Messungen / Measurements

Verankerungen / Moorings