FN Archimer Export Format
PT J
TI A joint electromagnetic and seismic study of an active pockmark within the hydrate stability field at the Vestnesa Ridge, West Svalbard margin
BT 
AF GOSWAMI, Bedanta K.
   WEITEMEYER, Karen A.
   MINSHULL, Timothy A.
   SINHA, Martin C.
   WESTBROOK, Graham
   CHABERT, Anne
   HENSTOCK, Timothy J.
   KER, Stephan
AS 1:1;2:1;3:1;4:1;5:1,2,3;6:1,4;7:1;8:3;
FF 1:;2:;3:;4:;5:;6:;7:;8:PDG-REM-GM;
C1 Univ Southampton, Ocean & Earth Sci, Natl Oceanog Ctr Southampton, Southampton, Hants, England.
   Univ Birmingham, Sch Geog Earth & Environm Sci, Birmingham, W Midlands, England.
   IFREMER, Ctr Brest, Geosci Marines, Plouzane, France.
   Fugro EMU Ltd, Southampton, Hants, England.
C2 UNIV SOUTHAMPTON, UK
   UNIV BIRMINGHAM, UK
   IFREMER, FRANCE
   FUGRO EMU LTD, UK
SI BREST
SE PDG-REM-GM-LGG
   PDG-REM-GM
IN WOS Ifremer jusqu'en 2018
   copubli-europe
IF 3.318
TC 50
UR https://archimer.ifremer.fr/doc/00283/39458/37928.pdf
LA English
DT Article
DE ;gas hydrate;Svalbard;CSEM;saturation;pockmark;Vestnesa
AB We acquired coincident marine controlled-source electromagnetic (CSEM), high-resolution seismic reflection and ocean-bottom seismometer (OBS) data over an active pockmark in the crest of the southern part of the Vestnesa Ridge, to estimate fluid composition within an underlying fluid-migration chimney. Synthetic model studies suggest resistivity obtained from CSEM data can resolve gas or hydrate saturation greater than 5% within the chimney. Acoustic chimneys imaged by seismic reflection data beneath the pockmark and on the ridge flanks, were found to be associated with high-resistivity anomalies (+2-4 m). High-velocity anomalies (+0.3 km/s), within the gas hydrate stability zone (GHSZ) and low-velocity anomalies (-0.2 km/s) underlying the GHSZ, were also observed. Joint analysis of the resistivity and velocity anomaly indicates pore saturation of up to 52% hydrate with 28% free gas, or up to 73% hydrate with 4% free gas, within the chimney beneath the pockmark assuming a non-uniform and uniform fluid distribution respectively. Similarly, we estimate up to 30% hydrate with 4% free gas or 30% hydrate with 2% free gas within the pore space of the GHSZ outside the central chimney assuming a non-uniform and uniform fluid distribution respectively. High levels of free-gas saturation in the top part of the chimney are consistent with episodic gas venting from the pockmark.
PY 2015
PD OCT
SO Journal Of Geophysical Research-solid Earth
SN 0148-0227
PU Amer Geophysical Union
VL 120
IS 10
UT 000366842400007
BP 6797
EP 6822
DI 10.1002/2015JB012344
ID 39458
ER

EF