Woods Hole Coastal and Marine Science Center
The U.S. Geological Survey Gas Hydrates Project
Submarine Slope Destabilization
For decades, it has been postulated that submarine slope failures are spatially linked to the presence of gas hydrates/gas-charged sediments and temporally linked to episodes of climate change. The evidence for these linkages remains anecdotal, and increasingly the causal relationship between gas hydrates and slope failures is being questioned. More likely, gas hydrates and/or associated gas charging play a role in pre-conditioning slopes for failure. When triggered by earthquakes, oversteepening of sediments, or other factors, slopes containing gas hydrates/gas may fail. Several types of studies are required to clarify the relationships among slope failures, gas hydrates, and climate change. One of the key needs is determining whether currently-observed charging of sediments with methane gas and/or hydrate leads or lags the timing of slope failures.
Swath bathymetric map of the Cape Fear submarine slide, the largest slide on the US Atlantic coast. Data were collected on the R/V Atlantis in 2003.
Schematic showing the theoretical impact of falling sea level on the stability of methane hydrate and gas-charged submarine slopes.
USGS scientists have a long tradition of studying submarine slope failures and were among the first to note a spatial link between slope failures and gas hydrates/gas-charged sediments. USGS Gas Hydrates scientists support the USGS Hazards Mission area through field-based surveys that refine understanding of this association and through geotechnical studies that evaluate the response of sediments to dissociation of gas hydrate. In recent years, USGS Gas Hydrates Project scientists have studied the Cape Fear Slide, the Storegga Slide, and slides on the US Beaufort margin
Hornbach, M., L. Lavier, and C. Ruppel, 2007, Triggering mechanism and tsunamogenic potential of the Cape Fear Slide complex, U.S. Atlantic coastal margin, Geochem. Geophys. Geosyst., 8, Q12008 (doi:10.1029/2007GB001722
Kayen, R., and H. Lee, 1991, Pleistocene slope instability of gas hydrate-laden sediment on the Beaufort sea margin, Marine Geotechnology, 10, 125-141.
Lee, J. Y., J. C. Santamarina, and C. Ruppel, 2010, Volume change associated with formation and dissociation of hydrate in sediment, Geochem. Geophys. Geosyst., 11, Q03007, doi:10.1029/2009GC002667.
Paull, C.K., Ussler, W. III, Holbrook, W.S., Hill, T.M., Keaten, R., Haflidason, H., Johnson, J.E., Winters, W.J., and Lorenson, T.D., 2007, Origin of pockmarks and chimney structures on the flanks of the Storegga Slide, Offshore Norway, Geo-Marine Letters, DOI 10.1007/s00367-007-0088-9. )
Paull, C.K., Ussler, W. III, Holbrook, W.S., Hill, T.M., Haflidison, H., Winters, W., Lorenson, T., Aiello, I.,Johnson, J., Lundsten, E., 2010, The tail of the Storegga Slide, Sedimentology, v. 57, p. 1409-1429.
Yun, T.S., J.C. Santamarina, and C. Ruppel, 2007, Mechanical properties of sand, silt, and clay containing synthetic hydrate, Journal of Geophysical Research, 112, B04106. (doi: 10.1029/2006JB004484)