Monsoon trough of the summertime Asian monsoon is in its normal orientation (oriented east-southeast to west-northwest), tropical cyclones along its periphery will move with a westward motion. If it reverses its orientation, orienting southwest to northeast, tropical cyclones will move more poleward. Tropical cyclone tracks with S-shapes tend to be associated with reverse-oriented monsoon troughs. The South Pacific convergence zone and South American convergence zones are generally reverse oriented. The failure of the monsoon trough, or the ITCZ, to move south of the equator in the eastern Pacific Ocean and Atlantic Ocean during the southern hemisphere summer, is considered one of the
Nankai Trough beneath the overriding plate (Obana et al., 2006). Recent large scale earthquakes resulting from subduction along the Nankai Trough have occurred in areas of large scale increases in the dip angle of the subducting plate (Hori et al., 2004). The trough is potentially a major source of hydrocarbon fuel, in the form of methane clathrate. However, there is no commercial exploitation. At depth in the ocean bottoms, in some cases water can form an ice-like solid structure that has methane trapped in its crystalline lattice, forming gas hydrates. The source of water for the formation of gas hydrates frequently comes