- The Marianas Islands were formed by a volcanic island arc resulting from the subduction of the Pacific Plate beneath the Mariana Plate. The classic configuration of forearc, volcanic arc, and back-arc are present as well as an older remnant arc formed as the Mariana Trough expanded. In front of the arc is the #2550km long by 69km in width Mariana Trench which is the deepest oceanic trench at ~11km deep.
- There are 15# islands with 14# in the Commonwealth of Northern Mariana Islands and 1# being Guam. Principal islands after Guam are Saipan, Tinian, and Rota.
- The arc is ~1370km long and includes ~76# volcanic systems. ~26# are active with ~20# submarine volcanoes and 6# aerial volcanoes.
- One of the islands with geothermal potential is Pagan Island that has been researched previously and estimated to have an active geothermal systems (shallow hydrothermal reservoir) with electrical generating capacity of 50-125MW. Surface manifestations and extensive alteration have been investigated.
