The temperature under the seabed indicates various phenomena occurring in the Earth’s interior, which can be affected by the changes in the environment above the ground. We can know fault activities, fluid migration, and the temperature of the Earth’s surface in the past by measuring the temperature of the subsurface. The seminar will introduce the measurement of the temperature under the seafloor, including temperature estimation using acoustic reflectors formed by methane hydrates that are widely distributed in the oceans.

Sea ice can be found in the Arctic Ocean and around Antarctica. Sea ice is important for the global climate and ship navigation. However, the processes that affect the growth and loss of sea ice are complex and involve various factors, including the atmosphere, waves, and currents, which makes it difficult to estimate and predict the sea ice conditions. The seminar will introduce satellite and field observations of sea ice in the polar regions.