Blake Outer Ridge Seismic Data

The data used in this study were recorded at the Blake Outer Ridge, offshore Florida and Georgia. A map of the region is shown in Figure , highlighting the area of known hydrate distribution as mapped from seismic bottom simulating reflectors (BSR). The part of the seismic line analyzed in this thesis is marked by the rectangular, and extends both from the hydrate region into an area without hydrate. The map also displays the position of six wells drilled at the Carolina and Blake Outer Ridge. Velocity information of wells 994, 995 and 997, which were several hundred meters deep and penetrated through zones of hydrate-saturated sediments, will be used later in this study. The sediments in the region are fairly uniform with no major lithological changes within several hundred meters of the seafloor. Most of the sediment consists of clay and nannofossils with small amounts of quartz. They are highly unconsolidated and are therefore characterized by large porosities.

 

map2
Figure 1 Map of the region after Matsumoto et al. (1996).

The data consists of 1050 CMP gathers with a 50 m CMP spacing recorded with a non-linear streamer. This resulted in a 100 m group spacing at the near-offset traces and a 50 m group spacing at the far offset traces. The streamer length is approximately 3.6 km.