Alaska Time Zone to 03:00 LDT on the second Sunday in March and returns at 02:00 LDT to 01:00 LST on the first Sunday in November. Two time zones have been referred to as the "Alaska Time Zone": a zone based on UTC−10 that covered much of Central Alaska in the early 20th century, and a zone based on UTC−9 zone that has covered all of the state except the Aleutian Islands since 1983. The Standard Time Act of 1918 authorized the Interstate Commerce Commission to define each time zone. The United States Standard Alaska Time was designated as UTC−10. Some references prior
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