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 andesite, while the middle crust is composed of 5 km-thick mid-ocean ridge basalt (MORB), and 19 km- thick tholeiitic residue in the lower crust. Continental crusts usually have silicic upper crust and reflective lower crust, but these features are not found in the Aleutian arc. There are 40 active volcanoes in the Aleutian volcanic arc from the Mt. Spurr in mainland Alaska to Buldir Island in the far west Aleutian islands. The list of volcanoes in the Aleutian Arc could be found here. The eastern end of the volcanic arc on the Alaska Peninsula lies on Mesozoic sedimentary and volcanic