Haakon Mosby Mud Volcano: Marine Gravity Data


Contact
rkrocker [ at ] awi-bremerhaven.de

Abstract

During a recent cruise of the German R/V Polarstern, detailed investigations of the Haakon Mosby Mud Volcano (HMMV) have been carried out. In addition to bathymetric measurements and biological, geophysical and geochemical data acquisition, gravity survey lines were placed across HMMV.HMMV is located at the continental slope of the western Barents Sea between Norway and Svalbard in a water depth of 1270m. The central volcano structure has a diameter of almost 1km.The mean ship speed during the survey was 11knots. The weather was calm and is not expected to degrade the quality of the gravity measurements (wind speed 1-3Bft).Altogether gravity along approx. 400km survey lines were recorded around HMMV. Nine parallel survey lines (90km) have been placed in N-S direction in order to reduce the Eötvös effect. They cover an area of about 2.5km by 10km in E-W and N-S direction respectively. The dense line spacing is used to identify also small scale gravity variations. Additional long lines of various directions, parallel and perpendicular to the continental slope, were recorded to adjust the local gravity data to global data. However global data sets such as Sandwell and Smith predicted gravimetry or EGM96 turned out to be not adequate for comparison in detail.For data processing we extracted straight line segments from the whole data set in order to exclude data recordings during ship turns. Existing outliers were eliminated manually. The data processing included Eötvös correction, Bouguer and topographical correction. The density of the crust was determined to 2.2g/cm3 using Nettleton Method based on the recorded gravity data. Cross over differences adjustment (COD) based on 35 points resulting in a RMS of 0.56mgal.Despite the effort to extract small scale gravity variations at the center of HMMV, no significant variation of gravity anomalies have been found. However, a lower gravity value was determined around HMMV with respect to the wider surroundings.Gravity data of HMMV are presented and linked to the bathymetry.



Item Type
Conference (Poster)
Authors
Divisions
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Peer revision
Not peer-reviewed
Publication Status
Published
Event Details
EGU General Assembly 2004, Nice, FranceApril 2004..
Eprint ID
10458
Cite as
Krocker, R. , Beyer, A. , Rathlau, R. and Schenke, H. W. (2004): Haakon Mosby Mud Volcano: Marine Gravity Data , EGU General Assembly 2004, Nice, FranceApril 2004. .


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