Types of volcanic eruptionsSeveral types of volcanic eruptions—during which lava, tephra (ash, lapilli, volcanic bombs, and volcanic blocks), and assorted gases are expelled from a volcanic vent or fissure—have been distinguished by volcanologists. These are often named after famous volcanoes where that type of behavior has been observed. Some volcanoes may exhibit only one characteristic type of eruption during a period of activity, while others may display an entire sequence of types all in one eruptive series.
LavaLava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or underwater, usually at temperatures from . The volcanic rock resulting from subsequent cooling is also often called lava. A lava flow is an outpouring of lava during an effusive eruption. (An explosive eruption, by contrast, produces a mixture of volcanic ash and other fragments called tephra, not lava flows.
Hawaiian IslandsThe Hawaiian Islands (Hawaiian: Nā Moku o Hawai‘i) are an archipelago of eight major volcanic islands, several atolls, and numerous smaller islets in the North Pacific Ocean, extending some from the island of Hawaii in the south to northernmost Kure Atoll. Formerly the group was known to Europeans and Americans as the Sandwich Islands, a name that James Cook chose in honor of the 4th Earl of Sandwich, the then First Lord of the Admiralty.
Mauna LoaMauna Loa (ˌmɔːnə_ˈloʊ.ə or ˌmaʊnə_ˈloʊ.ə; Hawaiian: ˈmɐwnə ˈlowə; Long Mountain) is one of five volcanoes that form the Island of Hawaii in the U.S. state of Hawaii in the Pacific Ocean. The largest subaerial volcano (as opposed to subaqueous volcanoes) in both mass and volume, Mauna Loa has historically been considered the largest volcano on Earth, dwarfed only by Tamu Massif. It is an active shield volcano with relatively gentle slopes, with a volume estimated at , although its peak is about lower than that of its neighbor, Mauna Kea.
Mauna KeaMauna Kea (ˌmO:nə_ˈkeɪə or ˌmaʊnə_ˈkeɪə; ˈmɐwnə ˈkɛə; abbreviation for Mauna a Wākea) is an inactive volcano on the island of Hawaii. Its peak is above sea level, making it the highest point in the state of Hawaii and second-highest peak of an island on Earth. The peak is about higher than Mauna Loa, its more massive neighbor. Mauna Kea is unusually topographically prominent for its height: its wet prominence is fifteenth in the world among mountains, at ; its dry prominence is .
SeamountA seamount is a large submarine landform that rises from the ocean floor without reaching the water surface (sea level), and thus is not an island, islet, or cliff-rock. Seamounts are typically formed from extinct volcanoes that rise abruptly and are usually found rising from the seafloor to in height. They are defined by oceanographers as independent features that rise to at least above the seafloor, characteristically of conical form. The peaks are often found hundreds to thousands of meters below the surface, and are therefore considered to be within the deep sea.
Hawaii (island)Hawaii (həˈwaɪʔi ; Hawaii həˈvɐjʔi) is the largest island in the United States, located in the state of Hawaii. It is the southeasternmost of the Hawaiian Islands, a chain of volcanic islands in the North Pacific Ocean. With an area of , it has 63% of the Hawaiian archipelago's combined landmass. However, it has only 13% of the archipelago's population. The island of Hawaiʻi is the third largest island in Polynesia, behind the north and south islands of New Zealand.
MarsMars is the fourth planet and the furthest terrestrial planet from the Sun. The reddish color of its surface is due to finely grained iron(III) oxide dust in the soil, giving it the nickname "the Red Planet". Mars's radius is second smallest among the planets in the Solar System at . The Martian dichotomy is visible on the surface: on average, the terrain on Mars's northern hemisphere is flatter and lower than its southern hemisphere. Mars has a thin atmosphere made primarily of carbon dioxide and two irregularly shaped natural satellites: Phobos and Deimos.
VolcanoA volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates are diverging or converging, and most are found underwater. For example, a mid-ocean ridge, such as the Mid-Atlantic Ridge, has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates.
Olympus MonsOlympus Mons (pronəˌlɪmpəs_ˈmɒnz,_oʊˌ-; Latin for Mount Olympus) is a large shield volcano on Mars. It is over 21.9 km (13.6 mi or 72,000 ft) high, as measured by the Mars Orbiter Laser Altimeter (MOLA), and is about two and a half times Mount Everest's height above sea level. It is one of Mars's largest volcanoes, its tallest planetary mountain, and is approximately tied with Rheasilvia as the tallest mountain currently discovered in the Solar System. It is associated with the Tharsis Montes, a large volcanic region on Mars.