Hawaii–Aleutian Time Zone Hawaii–Aleutian Time Zone The Hawaii–Aleutian Time Zone observes Hawaii–Aleutian Standard Time (HST), by subtracting ten hours from Coordinated Universal Time (). The clock time in this zone is based on the mean solar time of the 150th meridian west of the Greenwich Observatory. The zone takes its name from the two areas it includes: Hawaii and the portion of Alaska's Aleutian Islands west of 169° 30′ W longitude. During daylight saving time, the Alaskan portion observes Hawaii–Aleutian Daylight Time (HDT, ), while Hawaii stays on standard time. From 1900 until 1947, GMT−10:30 was used as standard time in Hawaii. French
Geology of the United States streams downcut so rapidly that they cut right across the resistant folded rocks of the mountain core, carving canyons across rock layers and geologic structures. Most of Alaska consists of terranes accreted by collisions with island arcs carried in over the last 160 million years. These terranes were caused by the subduction of the Farallon, Kula, and Pacific plates sequentially. Currently, the Pacific plate is subducting beneath Alaska, producing the Aleutian arc series of volcanoes through the Alaskan Peninsula and Aleutian Islands. One of the sutures left by terrane addition is the Denali Fault, which curves through south-central Alaska. The