The stratovolcanoes are near the subduction zones of the tectonic plates. Japan has stratovolcanoes near the subduction zones of the tectonic plates. Mountains are formed through tectonic forces or volcanism. The lithosphere is subdivided into tectonic plates. Oceanic crust is the uppermost layer of the oceanic portion of a tectonic plate. Cold seeps occur over fissures on the seafloor caused by tectonic activity. Cocos Island is an oceanic island of both volcanic and tectonic origin. It becomes peat in good geochemical, sedimentary and tectonic conditions. The volcanoes are grouped into five volcanic belts with different tectonic settings. Another type of tectonic lake caused by faulting is sag ponds. They are grouped into five volcanic belts with different volcano types and tectonic settings. Indonesia has relatively high tectonic and volcanic activities. The lake is of mixed glacial and tectonic origin. Possible triggers of landslides are quakes caused by tectonic activity or impact events. They focus on seismic and tectonic activity by using a seismograph.