Hawaiʻi is the southernmost and largest island in the American state of Hawaii. It is located in the North Pacific Ocean and made up of a chain of five shield and hotspot volcanic mountains. The island is commonly referred as the Big Island or Big I to distinguish it from the state. It is administratively governed as Hawaiʻi County. It is the largest island in the United States and has an area of 4,028 square miles. Although the island accounts for 63% on the state's landmass, it is home to only 13% of the population. Big Island is the third third-largest Island in the Pacific, after the two main islands of New Zealand. The largest city on the island is Hilo, although there are no incorporated cities in the county. Formation of the island began millions of years ago when the Earth's crust below the Pacific Ocean crept over a heat hotspot, which melted the rocks below the crust, transforming it into magma.
As magma collects, pressure builds, forcing it upwards with enough force to break through the Earth's outer surface and pop out of the ocean. Over time the lava hardens to form an island, which is anchored to the Earth's crust. When the pressure decreases, the conduit of the mountain collapses and magma begins to collect again. When enough pressure is generated, it forces the magma out of the conduit in a mass explosion or through fissures that appear at ground level.
The island of Kohala occupies the northwest portion of the Big Island. It was formed by Mount Kohala, which is the oldest of the five volcanoes. It is estimated to be one million years old. Kohala covers an area of 234 square miles, which represents about 6% of the island. The mountain's last major eruption occurred 120,000 years ago. A massive landslide that occurred 250,000 to 300,000 years ago destroyed the northeast part on the mountain and reduced its height by 3,300 feet. The volcanic island is administratively divided into North Kohala and South Kohala.
4. Mauna Kea
Mauna Kea is tallest of the volcanic mountains in the state of Hawaii. The mounting stands 13,802 feet above the sea level, but a large proportion of it lies below the ocean. The length of the mountain from the ocean base is 33,000 feet, making it the tallest mountain on Earth. It is about one million years old. Mauna Kea is dormant because it last erupted 4,000-6,000 years ago. It is the only mountain in Hawaii that shows evidence of glaciation.
Hualālai is the third youngest, the westernmost, and the third most active volcano on the island. The mountain rises 8,271 feet above sea level. It last erupted in 1801 after being inactive for more than two thousand years. The mountain is considered active because it is expected to erupt within the next century. Hawaiian natives have lived on the foot of the mountain for centuries.
2. Mauna Loa
Mauna Loa is the second largest volcanic mountain by area on Earth after Tamu Massif. The active volcanic mountain last erupted in 1984. It is 13,679 feet long and covers an area of 2,000 square miles. Although the mountain is active, it erupts gently because its magma is silica-poor and very fluid. The eruption in 1984 did not cause casualties, but geologists list the mountain among the most dangerous in the world.
Kīlauea is the most active volcano in Hawaii. It was formed between 300,000 and 600,000 years ago, but emerged above seal level 100,000 years ago. Kīlauea has erupted continuously since 1983, destroying property. In May 2018, the mountain began erupting and forming several lava vents that oozed lava continuously. By mid-June of that year, the mountain was still erupting, and dozens of homes had been razed to the ground by lava.