landslides. Furthermore, the scientific study aimed to develop new safety techniques guarding against any hazardous conditions created by gas hydrate drilling and pipeline construction and give insights into drilling and production technology with regard to a new industrial development. In late 1999 and early 2000, the Japan Ministry of Economy, Trade and Industry (METI, formerly known as the Japan Ministry of International Trade and Industry, MITI) commissioned six exploration wells that were successfully drilled at a water depth of 945 meters in the eastern Nankai Trough region, 50 km off the coast near Tokyo Bay, to characterize the natural gas hydrate deposits and investigate their overall commercial potential. Two wells were drilled in order to develop an appropriate casing program. The third well was drilled to 3,000 meters below sea-level in order to analyze the composition of the different strata and assess the contained gas. Seismic data showed a well-defined bottom simulating reflector, marking the bottom of the gas hydrate stability zone, found in a depth of 290 meters below the seafloor (1,240 meters below sea-level). Cores were taken in a depth between 1,152 and 1,210 meters, revealing the presence of gas hydrates in three different zones, with the hydrates accounting for 20% of the bulk volume and 80% of the pore space. These three different zones mostly consist of heterogeneous turbiditic sandstones that show permeabilities between 30 and 40% and are either continuous or discontinuous. The gas trapped inside the clathrates is predominantly biogenic and hints to a progressive decrease in microbial activity with depth and an additional upward migration throughout the sediment column. Based on these exploration results, the Japanese government initiated the 16-year methane hydrate R&D research program in 2001. Leading project partners included the Japan National Oil Corporation (formerly known as JNOC, now Japan Oil, Gas and Metals National Corporation – JOGMEC), the Japanese Petroleum Exploration (JAPEX), the United States Department of Energy (DOE) as well as other industry partners. Together with the Japanese Ministry of Economy, Trade and Industry (MITI) they form a consortium named ‘MH21 – The Research Consortium for Methane Hydrate Resources in Japan’, whose overall aim it is to establish a process for commercial production from offshore gas hydrates by the year 2018. In addition to the national R&D research program, there have been cruise expeditions carried out at drill observation wells in the Nankai Trough region by the Integrated Ocean Drilling