Timeline of the 2015 Pacific hurricane season of 215 mph (345 km/h). Four time zones are utilized in the basin: Central for storms east of 106°W, Mountain between 114.9°W and 106°W, Pacific between 140°W and 115°W, and Hawaii–Aleutian for storms between the International Date Line and 140°W. However, for convenience, all information is listed by Coordinated Universal Time (UTC) first with the respective local time included in parentheses. This timeline includes information that was not operationally released, meaning that data from post-storm reviews by the National Hurricane Center is included. This timeline documents tropical cyclone formations, strengthening, weakening, landfalls, extratropical transitions, and dissipations during the season. December
Aleutian subduction zone rocks, with trace amounts of Paleozoic rocks intruded by Mesozoic batholiths. Most of the Aleutian Islands are composed of sedimentary rocks from granitic and metamorphic rocks from Oligocene-Miocene. There are Quaternary volcanoes on the north of the Aleutian Islands structural axis, which is composed of andesite mostly, mixed with olivine basalt to rhyolite. The eastern Aleutian volcanoes have more silicic magma while the western Aleutian arcs lack the sial magma. The Aleutian Trench formation is associated with the subduction of the Pacific Plate beneath the North American plate. The horizontally-curved shape of the trench is due to the change in