Knowledge Bank

Seismic interpretation is one of the first things that are done after a seismic data set has been attained and processed. This interpretation acts as a guideline to where possible drilling hazards would be located and could be used as a starting point for further research into future drilling expeditions in the area. In this thesis, I obtained a public 3-D seismic dataset from the U.S. Geological Survey National Archives of Marine Seismic Surveys that is located near the Mississippi Canyon in the northern Gulf of Mexico and that imaged a variety of near-seafloor features that had not been previously described in the scientific literature. I focused on the analysis and interpretation of three seafloor features based on their prominent amplitude anomalies and structural properties. Feature #1 contained a halo-like amplitude anomaly and is interpreted as a gas seep in which underlying salt facilitated upward fluid migration to the surface. Feature #2 has a consistent circular anomaly that was determined to be a salt diapir extruding at the seafloor. Feature #2 also contained a bottom simulating reflector which may indicate the presence of gas hydrate. Feature #3 had no amplitude anomaly but rather an elevation anomaly that is likely gas-free roof sediments overlying the same salt diapir that affected features #1 and #2. A key finding made possible by having three-dimensional seismic data is that the salt body is one continuous body, not individual bodies. The near-seafloor conditions in this study area suggest that fluid flow, gas, and salt tectonics are active in the present-day.