The islands of Hawaii are made from volcanic rock.
Many of the nearly 170 volcanoes in the United States are centered along the western seaboard of the nation, in the Cascade Range from British Columbia to California. They are also found in Hawaii and Alaska, which by far has the largest amount. The majority of the volcanoes in the U.S. are not considered to be high threat, as rated by the United States Geological Survey.
Alaska
Alaska is home to more than 130 of the nation's nearly 170 volcanoes, with 75 percent of all volcanoes that have erupted in the U.S. within the past 200 years. They are mostly located along the western Aleutian Arc, which creates what is known as the Ring of Fire. In 1912, volcanoes Novarupta and Katmai caused the largest eruption in the 20th century. The 1990s were an active time in Alaska, with Redoubt, Spurr, Akutan and Makushin all erupting between 1990 and 1995.
Hawaii
Hawaii may only have around 13 volcanoes, but those volcanoes are the islands. Hawaii is the only U.S. state that is completely composed of volcanic rock. The chain of islands are volcanoes that connect to the floor of the Pacific Ocean. Mauna Loa, located on the big island of Hawaii, is by far the largest, responsible for 85 percent of the state's land. It last erupted in 1984. The big island has six more volcanoes and the islands of Maui, Molokai and Oahu each have two.
Washington
Washington is home to hundreds of small, non-threatening basaltic volcanoes, but has only five major volcanoes. These are classified as composite volcanoes, and the U.S. houses 13 in the Cascade Range. The five that fall in Washington's borders are Mount Baker, Glacier Peak, Mount Adams, Mount Ranier and Mount St. Helens. Mount St. Helens, probably the best-known modern day volcano in the U.S., erupted on May 18, 1980, and was the most destructive in U.S. history, killing 57 people and causing $860 million in damage.
Oregon
Oregon also falls in the Cascade Range and is home to many small, ineffective volcanoes and five active volcanoes. The active volcanoes are Crater Lake, Newberry Caldera, Three Sister, Mount Jefferson and Mount Hood. Mount Hood is the farthest north in the state and falls in a rather active seismic region along with Mount St. Helens, just across the border in Washington. Despite its near-constant tiny rumbling activity, Mount Hood has not erupted since the 1790s.
California
California is home to six active volcanoes. The northern portion of the state is included in what makes up the southern tip of the Cascade Range. Three of California's volcanoes fall into this range. They are Medicine Lake, Mount Shasta and Lassen Peak. The Lassen Volcanic Complex, as it is known, is where the Cascade Range comes to an end. Mount Shasta erupted in 1786 and Lassen Peak in 1917. Three other volcanoes, Clear Lake, Long Valley and Coso, are located farther south in California.
Tags: Cascade Range, active volcanoes, Mount Helens, Mount Hood, along western
