HR: 0830h
AN: OS51B-0852    [PDF]
TI: 3D and 2.5D Prestack Depth Migration of Hydratech OBS Data
AU: * Matthias, Z
EM: mzillmer@geomar.de
AF: GEOMAR, Wischhofstr. 1-3, Kiel, 24148 Germany
AU: Reston, T
EM: treston@geomar.de
AF: GEOMAR, Wischhofstr. 1-3, Kiel, 24148 Germany
AU: Klaeschen, D
EM: dklaeschen@geomar.de
AF: GEOMAR, Wischhofstr. 1-3, Kiel, 24148 Germany
AU: Flueh, E
EM: eflueh@geomar.de
AF: GEOMAR, Wischhofstr. 1-3, Kiel, 24148 Germany
AB: The Hydratech project investigates the amount of gas hydrate in the pore space of sediments at continental margins. Four active seismic experiments were performed at the continental slope of western Svalbard and in the Storegga area using Ocean Bottom Hydrophones (OBH) and Seismometers (OBS). Three OBH/OBS arrays with 20 instruments were deployed with a spacing of 400 metres between OBS and one line profile with 600 metres instrument spacing. The OBS array data is used for a 3D prestack depth migration, which leads to an image of the subsurface and to a velocity model. The image of the sediments has a lateral extension of 2 x 2 km and it reaches 400 metres in depth bsf. The Bottom Simulating Reflector (BSR), which marks the base of the gas hydrate stability zone, can be identified in the northern Svalbard area at a depth of 200 metres bsf. Below the BSR there is a low velocity zone of 125 metre thickness, where the P wave velocity decreases from 1800 m/s to 1200 m/s. The image of the 2D line of the Storegga area shows a thin layer of 10 metre thickness, where the P wave velocity decreases to 1000 m/s. Both low velocity zones can be explained by the presence of free gas in the sediments.
DE: 3025 Marine seismics (0935)
SC: Ocean Sciences [OS]
MN: 2003 Fall Meeting