Interesting facts about volcanos The name “volcano” has its origin from the name of Vulcan, a god of fire in Roman mythology. Earth has more than 1,500 active volcanoes. The largest volcano in the world is Mauna Loa. It has a volume of about 40,000 cubic kilometers, and an above-sea level area of 5125 square kilometers. The most common type of lava – called basalts – usually have eruption temperatures of about 1150–1200 °C. The highest volcano is Ojos del Salado in Chile. It is 22,589 feet (6,887 m) tall. More than 80% of the Earth’s surface is volcanic in origin. About 500 million people live close to active volcanoes! Somewhere, around the world, there are 20 active volcanoes erupting as you’re reading this. Between 50–70 volcanoes erupted last year, and 160 went off in the last decade. The names of some famous volcanoes are: Mount St. Helens, Muana Loa, Lassen Peak, Mount Rainier, and Mount Olympus. The oldest volcano is probably Etna and that is about 350,000 years old. The Indonesian volcano, Tambora, which erupted in 1815 produced so much ash that world temperatures fell sharply in the following year. New England, in the eastern USA, had severe frosts in August. The loudest sound in the history of mankind was caused by a volcanic eruption at Krakatoa, near Java in 1883. The sound was so powerful that it was heard in Australia, which is 5000 km far from Krakatoa. The highest volcano ever discovered is not on Earth, but on Mars! Olympus Mons, the highest volcano in the Solar System, is about 16.5 miles (26.4 km) high — more than four times as high as Mount Kilimanjaro, the highest volcano on Earth. Io, one of Jupiter’s moons, is the most volcanically active body in the Solar System after Earth. Nine volcanoes have been observed on Io’s surface, some eruptions ejecting material at speeds of 1 kilometer (0.6 miles) per second, and sending debris up to 300 kilometers (190 miles) above the surface! It is believed that Io’s volcanic activity is created by the moons Europa and Ganymede, whose gravitational forces pull against the gravity of Jupiter. The resultant tug-of-war causes distortions in Io’s surface of up to 100 meters (330 feet) and fuels its volcanic activity. When lava begins to cool, it solidifies and forms a crust that helps insulate the still molten lava underneath. Basaltic lava can form a crust strong enough to stand on in 10 to 15 minutes. This crust slows the cooling of the lava underneath and it may take several months to cool. Thick lava flows cool even more slowly. A lava flow that is 100 feet (30 m) thick may take several years to completely solidify. Thicker lava flows can take even longer. In 1959, lava filled a pit crater on Kilauea Iki in Hawaii. The depth of the lava pond was about 300 feet (100 m). In 1988, geologists drilled core samples of the lava pond and found that there was still some molten lava at the bottom. Established in 1916, Hawaii Volcanoes National Park has two of the most active volcanoes in the world: Mauna Loa and Kilauea. Joining them are the inactive Mauna Kea, Kohala, and Hualalai. Ancient Hawaiians worshiped Pele, goddess of volcanoes, and believed her wrath caused the mountains’ eruptions that destroyed their villages and agricultural lands. Not everything is destroyed by lava. Within weeks of lava’s hardening, plants appear in hardened lava’s cracks where moisture accumulates. Soon other plant life settles in, nurtured by the abundant tropical storms, and rain forests appear, as do unusual animal life.