Gas hydrate is known and inferred to occur on the Blake Ridge within the depth interval from about 185 to 450 mbsf. Based primarily on core-derived physical property data, the average sediment porosities within the gas hydrate-bearing interval on the Blake Ridge have been determined to range from about 57% to 58%. The standard and quick-look Archie relations yielded for the most part accurate gas-hydrate saturations, ranging from 0% to a maximum near 20%, within the ODP Leg 164 boreholes on the Blake Ridge. Downhole electrical resistivity log data have also been used to assess the volume of free gas beneath the gas hydrate accumulation on the Blake Ridge. The downhole log-derived gas-hydrate saturations, in combination with other reservoir data, indicate that the potential volume of gas within the log inferred gas hydrate at each drill site (Sites 994, 995, and 997) on the Blake Ridge ranges from about 670,000,000 to 1,450,000,000 m3 of gas per km2. Well log calculations from the Blake Ridge also indicate that the potential volume of gas within the log-inferred free-gas zones at each core site (Sites 994, 995, and 997) range from about 743,000,000 m3 of gas (at STP) per km2 at Site 997 to about 55,000,000 m3 of gas (at STP) per km2 at Site 995. Collectively, the volume of gas within the gas-hydrate and free-gas accumulations on the Blake Ridge may be about 57 trillion m3 of gas.