IFREMER, R/V "Pourquoi Pas?", October 29 to November 17, 2014
Chief scientist: L. Géli (Ifremer, Brest, France)
FLOWS participants: P. Henry (Aix-Marseille University, France); M. N. Çağatay (Istanbul Technical University, Turkey); L. Gasperini (ISMAR, Bologna, Italy)
The MARSITECRUISE project will carry out instrument deployments and sampling on the offshore strand of North Anatolian Fault in the Sea of Marmara, a transform-type plate boundary that exposes the city of Istanbul to a high earthquake hazard. This research cruise is planned within MARSITE (www.marsite.eu), a EU-FP7 3-years Supersite project, coordinated by KOERI (Kandilli Observatory and Earthquake Research Institute). The MARSITE project aims at harmonizing and combining seismological, geological, geophysical, geodetic and geochemical observations performed on land and at sea to improve seismic risk assessment and management. Scientific outcomes include better knowledge of: i) the post-seismic deformation of the 1999 Izmit earthquake and the signature of previous earthquakes, ii) the slip rates and interseismic loading rates on submarine and inland active fault segments iii) the transient signals and events, which includes microseismicity and earthquake precursors, related to strain within and around the fault zone. MARSITE work program at sea is the «monitoring of seismicity and fluid activity near the fault using existing cabled and autonomous multiparameter seafloor instrumentation ».
MARSITECRUISE of R/V Pourquoi pas ? is organized in 3 legs:
- Leg-1 (3 working days with ROV Victor) will deploy 10 geodetic transponders to characterize and quantify strain along the Istanbul-Silivri fault segment. Instruments will be recovered after 12 months of deployment with Geomar R/V Poseidon and then redeployed for 3 years. A temporary Ocean Bottom Seismometers (OBS) network will also be deployed around the geodetic monitoring site.
- Leg-2 (9 working days with ROV Victor) will perform geochemical sampling at fluid emission sites: long sediment cores for pore-fluid analyses; in situ gas sampling using Ifremer's ROV-Victor equipped with the PEGAZ system; water column sampling using a CTD-Rosette. Chemical and isotopic analysis (free and dissolved gases, gas hydrates, brines and pore waters, authigenic minerals) will further our understanding of fluid sources and migration pathways in the North Anatolian Fault Zone and of their long term temporal variations. Chemical sensor testing (methane sensors and Raman instrument) will complete the programme of Leg-2.
- Leg-3 (3 working days) will acquire long (up to 30 m length) sediment cores targeting horizons that will be dated to infer fault slip rates, and recover instruments deployed around fluid emissions sites located in the North Anatolian Fault Zone comprising piezometers, OBSs, and the Bubble OBservatory (BOB), a prototype for acoustic monitoring of bubble plumes.
The MARSITECRUISE Project involves scientists from the following institutions: Ifremer; CNRS (from 6 labs: IUEM-Brest, CEREGE-Aix-en-Provence, ISTERRE-Grenoble, LOCEAN-Paris, MNHN-Paris, CRPG-Nancy); INGV (Roma); CNR-Ismar (Bologna); Geomar (Kiel); ITU (Istanbul); KOERI (Istanbul); MTA (Ankara); DEU (University of Izmir); Lamont-Doherty Earth Observatory (USA).
THE CALAQUAKE 2014 CRUISE
(ISMAR CNR, R/V CNR URANIA – May 9, Messina- May 26, Naples):
FLOWS participant: L. Gasperini, Istituto di Scienze Marine (ISMAR)
The CALAQUAKE project (The CALabrian Arc subduction complex: active faults, historical earthQUAKEs and turbidites) is designed to carry out a multiscale-multidisciplinary study of deformation processes and relationships between tectonics and sedimentation in key areas of the Ionian Sea.
The Calabrian Arc (CA) is a narrow and arcuate subduction system resulting from Africa/Eurasia plate convergence and slab rollback in the Tyrrhenian region. Shortening is taken up by thrust faults in the accretionary wedge, while transtensive deformation accounts for margin segmentation along transfer tectonics systems, which are the shallow expression of deeply rooted processes.
Eastern Sicily and southern Calabria bear a historical record of destructive earthquakes often associated with tsunamis. Despite the detailed earthquake catalogue, knowledge of source parameters is still debated, and controversial interpretations exist especially for those earthquakes that may have been generated offshore, or along faults that extend into the submerged portion of the CA subduction system.
During the cruise, we will use a multi-scale and multidisciplinary approach involving the acquisition of high-resolution geophysical data and piston cores, which has the potential to reconstruct fault dynamics and relationships between shallow deformation, deeply rooted discontinuities and fluid flow within the accretionary wedge.
Download Final cruise report
MICROB II - MSM37
RV Maria S. Merian, Las Palmas/Spain (22.3.) to Cadiz/Spain (21.4.2014)
Chief scientist: H. Villinger, University of Bremen, Germany
FLOWS participant: H. Villinger, University of Bremen, Germany
Expedition MSM37 (MICROB II) aimed to investigate North Pond. It is an isolated northeast-trending sediment pond, approximately 8 km x 15 km in aerial extent, located on the western flank of the MAR at 22° 45'N, 46° 05'W. During IODP expedition 336 in the fall of 2011 two CORKs (borehole observatories) were installed, penetrating the sedimentary cover and reaching into the basement, predominantly for sampling crustal fluids for microbial studies.
The goals of the MSM37 cruise was to recover instrumentation which was deployed during MICROB I in the spring of 2012, to pump fluids from different horizons of the borehole for microbiological investigations and to download pressure data.
We used the ROV Jason II to accomplish the technically challenging tasks. The picture on the left shows a GeoMICROBE Sled (Cowen et al. , 2012), an instrumented longterm seafloor system which pumps fluids from three different horizons at CORK 1383C, North Pond. The system is monitoring flow rate, temperature, O2, pH and redox. Options for in situ filtration and large fluid sampling exist. The in-situ sampling tools allow for sampling and filtration of large volumes of water. We recovered successfully two of the installed GeoMICROBE Sleds and two Mega-Osmosamplers and in addition we pumped fluids from the boreholes using a system installed on the ROV for in situ filtration. The data download of pressure data from three CORKs was successful and a first analysis showed that the data are of excellent quality.