Benue Trough the Central African Shear Zone and for the volcanic island of St. Helena in the Atlantic ocean. Three periods of magmatic activity (volcanic action) have been identified, 147–106 Ma, 97–81 Ma and 68–49 Ma. The first is prominent in the north of the trough, and contemporary with magmatism in Brazil, probably occurring during a period of crustal extension before the Atlantic started to open. The second is found only in the south of the trough, and may belong to a period when the extension of the Atlantic had slowed down, ending with a period of compression. The third and last
Nankai Trough with the subducting young, hot Philippine Sea tectonic plate. At the targeted site, the geothermal gradient is about four times steeper than elsewhere in the Pacific Ocean. Reaching temperatures of approximately 130 °C in other areas would require collecting cores from approximately 4 kilometers below the seafloor, rather than 1.2 kilometers as planned. The Nankai Trough is the near-surface extension of a zone of active seismicity that dips beneath SW Japan. The rupture zone has been subdivided into five areas with respect to seismic modelling (Mitsui et al., 2004). These five subdivisions show interesting differences in earthquake behavior: frequency of