The Gambia has no migrating wildebeest, giraffes or any of the large animals commonly associated with Africa. However without leaving your hotel you can see a breathtaking variety of bird life, in addition to monkeys and lizards. Baboons and crocodiles can be seen nearby and then far up the river, hippos.
As the gasses collect in the magma chamber, the pressure rises. It is possible for the pressure to rise so much that the chamber cannot contain the magma and it erupts explosively. Some US Parks that have active volcanoes formed as the result of subduction related processes are: 1  Crater Lake National Park, OR.
Aside of mid-oceanic ridges, volcanoes occur most often above subducting slabs, forming island arcs and volcanic arcs. These volcanoes are typically stratovolcanoes. Additional volcanic activity is found in zones of crustal extension (continental rifts) where faulting provides a conduit for magma to reach the surface.