Deutsches Ozeanographisches
Datenzentrum Inventur der Sonne1-Reise SO215 (DOD-Ref-No.20110418)
Inventory of Sonne1 Cruise SO215 (DOD-Ref-No.20110418)

Plattform
Platform
Reise-Nr.
Cruise-No.
Zeitraum
Period
Projekt
Project
Arbeitsgebiet
Working area
Sonne1 SO215 25.04.2011 - 11.06.2011   Tasman Sea  

Fahrtleiter
Chief Scientist
Institut
Institute
Auslaufhafen
Port of departure
Einlaufhafen
Port of return
Stationskarte
Station map
Schiffsroute
Trackchart
Peirce Christine Durham University Auckland Townsville   

Ziel der Reise / Objectives of Cruise:

Subduction zones are dynamically evolving features that mark the sites of plate consumption and the recycling of sediment and magmatic material. The Tonga-Kermadec island arc-deep-sea trench system is an ideal study site as it is the most linear, fastest converging and most seismically active of any of the world's subduction zones, and the system has evolved over a long period of geological time (>50 Myr). The rapidity and obliqueness of convergence makes the Louisville Ridge-Tonga-Kermadec Trench an ideal locality to determine the mechanical response of the crust and lithosphere to loading and, hence, the integrated strength of the lithosphere. This is important for assessing whether the coupling between the subducting and overriding plates is 'soft' or 'hard' as well as providing constraints on rheological structure. The Tonga-Kermadec Trench collision with the Louisville Ridge is also associated with a seismic gap, especially so in shallow seismicity. This makes this also an ideal locality to test the 'Kelleher- McCann' hypothesis that bathymetric features on the subducting plate may control aspects of arc seismicity. Our scientific objectives were addressed by an integrated marine geophysical experiment that comprises simultaneous seismic reflection (MCS) and wide-angle (WA) refraction, gravity, magnetic, bathymetry and sub-seabed high-resolution imaging of the Louisville Ridge-Tonga-Kermadec Trench collision system. The acquisition geometry included: a) Profile A - a 400 km MCS/WA transect across the ridge-trench intersection, designed to determine the across-strike structure of the collision zone between the arc, across the forearc and trench, to the outer rise. Whilst also imaging the crust and uppermost mantle structure in the aseismic zone and high-curvature weak zone in the seaward wall of the trench, this profile also imaged deformation solely related to collision to allow distinction from that induced by seamount interaction with the overriding plate. b) Profile B - a 425 km MCS/WA transect across the Louisville Ridge and moat as they ride the trench outer rise, designed to determine the mode of isostatic compensation beneath the ridge at the northernmost part of the chain, and the effect of collision on the mechanical strength and flexural response of the subduction system. c) Profile C - a 725 km MCS/WA transect along the Louisville Ridge, traversing IODP drill sites. This transect extends across the Tonga-Kermadec Trench, and was designed to determine the structure of the Louisville Ridge (the pre-subduction crust), any along-ridge variation in crustal structure or underplating, how seamounts interact with the overriding plate upon their subduction, and how along-ridge variation in topography, crust and uppermost mantle structure relate to observed post-collision uplift. d) Profile D - a 350 km MCS transect designed to investigate pre-subduction crustal structure "background". e) Profile G - a 240 km MCS/WA transect designed to investigate the crustal structure of the forearc and deformation in the overriding plate. Along each WA profile ocean-bottom seismographs (OBSs) were deployed at ~10-15 km intervals, to record airgun shots from an array configured for contemporaneous MCS / WA acquisition. Gravity, magnetic and swath bathymetry data were acquired along all profiles.

Messungen / Measurements

Institut
Institute
Wissenschaftler
Scientist
Anzahl
Number
Einheit
Unit
Typ der Messungen
Type of measurements
Kommentar
Comments
Daten im DOD
Data in DOD
DURUNI Peirce Christine 1 deployment D90
Other physical oceanographic measurements
Sound velocity no
DURUNI Peirce Christine 126 deployment G26
Seismic refraction (no.of nautical miles)
Ocean-bottom seismograph (OBS) deployments no
DURUNI Peirce Christine 240 km G26
Seismic refraction (no.of nautical miles)
Profile G - wide-angle refraction seismic data - 4 component OBS no
DURUNI Peirce Christine 400 km G26
Seismic refraction (no.of nautical miles)
Profile A - wide-angle refraction seismic data - 4 component OBS no
DURUNI Peirce Christine 425 km G26
Seismic refraction (no.of nautical miles)
Profile B - wide-angle refraction seismic data - 4 component OBS no
DURUNI Peirce Christine 725 km G26
Seismic refraction (no.of nautical miles)
Profile C - wide-angle refraction seismic data - 4 component OBS no
DURUNI Peirce Christine 47 day(s) G27
Gravity measurements
Gravity - LaCoste-Romberg - Air-Sea meter, base tied pre- and post-cruise no
DURUNI Peirce Christine 3 survey G28
Magnetic measurements
Magnetics - SeaSpy no
DURUNI Peirce Christine 5 profiles G28
Magnetic measurements
Magnetics - SeaSpy no
DURUNI Peirce Christine 37 day(s) G74
Multi-beam echosounding
Atlas Parasound PS 70 no
DURUNI Peirce Christine 47 day(s) G74
Multi-beam echosounding
Swath bathymetry - Simrad EM120 no
DURUNI Peirce Christine 240 km G76
Multichannel seismic reflection
Profile G - 96 channel multichannel reflection seismic data - Sercel SEAL no
DURUNI Peirce Christine 350 km G76
Multichannel seismic reflection
Profile D - 96 channel multichannel reflection seismic data - Sercel SEAL no
DURUNI Peirce Christine 400 km G76
Multichannel seismic reflection
Profile A - 96 channel multichannel reflection seismic data - Sercel SEAL no
DURUNI Peirce Christine 425 km G76
Multichannel seismic reflection
Profile B - 96 channel multichannel reflection seismic data - Sercel SEAL no
DURUNI Peirce Christine 725 km G76
Multichannel seismic reflection
Profile C - 96 channel multichannel reflection seismic data - Sercel SEAL no
DURUNI Peirce Christine 24 deployment H13
Bathythermograph drops
Expendible bathymetric thermograph no
DURUNI Peirce Christine 1 n miles H80
Other physical measurements
Underway measurements during the whole trip such as coordinates, depth, meteorological parameter and so on yes
16.11.2019