Hawaii (island)

Hawaiʻi, also called the Island of Hawaiʻi, the Big Island or Hawaiʻi Island (/həˈwaɪ.i/ or /həˈwɑːiː/; Hawaiian: [həˈwɐiʔi] or [həˈvɐiʔi]), which comprises Hawaiʻi County and the Hilo, HI Micropolitan Statistical Area, is an island, county, and Micropolitan Statistical Area located in the U.S. state of Hawaii in the Hawaiian Islands. It is the largest and the southeastern-most of the Hawaiian islands, a chain of volcanic islands in the North Pacific Ocean. With an area of 4,028 square miles (10,430 km²), it is larger than all of the other islands in the archipelago combined and is the largest island in the United States. The island is often referred to as the "Big Island" to reduce confusion between the island and the state.

As of the 2010 Census the population was 185,079.^[3] The county seat and largest city is Hilo. There are no incorporated cities in Hawaiʻi County (see Hawaii Counties). Hawaiʻi County has a mayor-council form of government.

Hawaii County is one of seven counties in the United States to share the same name as the state in which it is located (the other six counties are Arkansas County, Idaho County, Iowa County, New York County, Oklahoma County, and Utah County).

According to the U.S. Census Bureau, the county has a total area of 5,086 square miles (13,170 km²), of which 4,028 square miles (10,430 km²) is land and 1,058 square miles (2,740 km²) (20.8%) is water.^[6] The county's land area comprises 62.7 percent of the state's land area. It is the highest percentage by any county in the United States. (Delaware's Sussex County comes in second at 48.0 percent, while Rhode Island's Providence County is third at 39.55 percent.)

In greatest dimension, the island is 93 miles (150 km) across and has a land area of 4,028 square miles (10,430 km²)^]comprising 62% of the Hawaiian Islands' land area. Measured from its sea floor base to its highest peak, Mauna Kea is the world's tallest mountain, taller than Mount Everest is above sea level

The Island of Hawaiʻi is built from five separate shield volcanoes that erupted somewhat sequentially, one overlapping the other. These are (from oldest to youngest):

• Kohala—extinct
• Mauna Kea—dormant
• Hualālai—active
• Mauna Loa—active, partly within Hawaiʻi Volcanoes National Park
• Kīlauea—active: has been erupting continuously since 1983; part of Hawaiʻi Volcanoes National Park

Geological evidence from exposures of old surfaces on the south and west flanks of Mauna Loa led to the proposal that two ancient volcanic shields (named Ninole and Kulani) were all but buried by the younger Mauna Loa.^[9] Geologists now consider these "outcrops" to be part of the earlier building of Mauna Loa. Another volcano which has already disappeared below the surface of the ocean is Māhukona.

Because Mauna Loa and Kīlauea are active volcanoes, the island of Hawaii is still growing. Between January 1983 and September 2002,lava flows added 543 acres (220 ha) to the island. Lava flowing from Kīlauea has destroyed several towns, including Kapoho in 1960, andKalapana and Kaimu in 1990. In 1987 lava filled in Queen's Bath, a large, L-shaped, freshwater pool in the Kalapana area.

Steam plume as Kīlauea red lava enters the ocean at three Waikupanaha and one Ki lava ocean entries. Some surface lava is seen too. The image was taken on April 16, 2008.

The southmost point in the 50 States of the United States, Ka Lae, is on Hawaii. The nearest landfall to the south is in the Line Islands. To the north of the Island of Hawaii is the Island of Maui, whose Haleakala volcano is visible from Hawaii across the Alenuihaha Channel.

About 35 km (22 mi) southeast of Hawaii lies the undersea volcano known as Loihi. Loihi is an erupting seamount that now reaches about 3,200 feet (980 m) below the surface of the ocean. Continued activity from Loihi will likely cause it to break the surface of the ocean sometime from 10,000 to 100,000 years from now.