A report on Volcano and Shield volcano

Bromo volcano in Indonesia. This country has more than 130 active volcanoes, one of which is a supervolcano, making Indonesia the country with the most active volcanoes in the world.

Cordillera de Apaneca volcanic range in El Salvador. The country is home to 170 volcanoes, 23 which are active, including two calderas, one being a supervolcano. El Salvador has earned the epithets endearment La Tierra de Soberbios Volcanes, (The Land of Magnificent Volcanoes).

An Ancient Greek warrior's shield–its circular shape and gently sloping surface, with a central raised area, is a shape shared by many shield volcanoes

Sabancaya volcano erupting, Peru in 2017

Skjaldbreiður is a shield volcano in Iceland, whose name means broad shield in Icelandic.

Cleveland Volcano in the Aleutian Islands of Alaska photographed from the International Space Station, May 2006

Scaled image showing Olympus Mons, top, and the Hawaiian island chain, bottom. Martian volcanoes are far larger than those found on Earth.

An eruption of Mount Pinatubo on June 12, 1991, three days before its climactic eruption

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Fountain of lava erupting from a volcanic cone in Hawaii, 1983

A pāhoehoe lava fountain on Kīlauea erupts

Aerial view of the Barren Island, Andaman Islands, India, during an eruption in 1995. It is the only active volcano in South Asia.

A lava lake in the caldera of Erta Ale, an active shield volcano in Ethiopia

Map showing the divergent plate boundaries (oceanic spreading ridges) and recent sub-aerial volcanoes (mostly at convergent boundaries)

Pāhoehoe flows enter the Pacific Ocean on Hawai{{okina}}i island

Lakagigar fissure vent in Iceland, the source of the major world climate alteration of 1783–84, has a chain of volcanic cones along its length.

Puʻu ʻŌʻō, a parasitic cinder cone on Kīlauea, lava fountaining at dusk in June 1983, near the start of its eruptive cycle

Skjaldbreiður, a shield volcano whose name means "broad shield"

Nāhuku, a famous lava tube on Hawai{{okina}}i island, now a tourist attraction in the Hawaiʻi Volcanoes National Park

Izalco volcano, the youngest volcano in El Salvador. Izalco erupted almost continuously from 1770 (when it formed) to 1958, earning it the nickname of "Lighthouse of the Pacific".

Cross-section through a stratovolcano (vertical scale is exaggerated):

Satellite images of the 15 January 2022 eruption of Hunga Tonga-Hunga Haʻapai

Pāhoehoe lava flow on Hawaii. The picture shows overflows of a main lava channel.

The Stromboli stratovolcano off the coast of Sicily has erupted continuously for thousands of years, giving rise to its nickname "Lighthouse of the Mediterranean"

Columnar-jointed basalt lava erupted from a volcano, South Penghu Marine National Park in Taiwan

Light-microscope image of tuff as seen in thin section (long dimension is several mm): The curved shapes of altered glass shards (ash fragments) are well preserved, although the glass is partly altered. The shapes were formed around bubbles of expanding, water-rich gas.

Fresco with Mount Vesuvius behind Bacchus and Agathodaemon, as seen in Pompeii's House of the Centenary

Narcondam Island, India, is classified as a dormant volcano by the Geological Survey of India

Fourpeaked volcano, Alaska, in September 2006 after being thought extinct for over 10,000 years

Mount Rinjani eruption in 1994, in Lombok, Indonesia

Capulin Volcano National Monument in New Mexico, US

Koryaksky volcano towering over Petropavlovsk-Kamchatsky on Kamchatka Peninsula, Far Eastern Russia

Schematic of volcano injection of aerosols and gases

Solar radiation graph 1958–2008, showing how the radiation is reduced after major volcanic eruptions

Sulfur dioxide concentration over the Sierra Negra Volcano, Galapagos Islands, during an eruption in October 2005

Comparison of major United States supereruptions (VEI 7 and 8) with major historical volcanic eruptions in the 19th and 20th century. From left to right: Yellowstone 2.1 Ma, Yellowstone 1.3 Ma, Long Valley 6.26 Ma, Yellowstone 0.64 Ma . 19th century eruptions: Tambora 1815, Krakatoa 1883. 20th century eruptions: Novarupta 1912, St. Helens 1980, Pinatubo 1991.

The Tvashtar volcano erupts a plume 330 km (205 mi) above the surface of Jupiter's moon Io.

Olympus Mons (Latin, "Mount Olympus"), located on the planet Mars, is the tallest known mountain in the Solar System.

A shield volcano is a type of volcano named for its low profile, resembling a warrior's shield lying on the ground.

- Shield volcano

Mafic lavas occur in a wide range of settings. These include mid-ocean ridges; Shield volcanoes (such the Hawaiian Islands, including Mauna Loa and Kilauea), on both oceanic and continental crust; and as continental flood basalts.

- Volcano

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Graph summarizing the eruptions of Kïlauea during the past 200 years. The Pu‘u ‘Ö‘ö- Kupaianaha eruption has continued into the 21st century. Information is sketchy for eruptions before 1823, when the first missionaries arrived on the Island of Hawai‘i. The total duration of eruptive activity in a given year, shown by the length of the vertical bar, may be for a single eruption or a combination of several separate eruptions.

Kīlauea

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Rainbow and volcanic ash with sulfur dioxide emissions from Halemaʻumaʻu

The Mauna Ulu eruption of 1969 generated a 300 m-high lava fountain

Lava from a fissure slowly advanced to the northeast on Hoʻokupu Street in Leilani Estates subdivision (May 5, 2018)

Kilauea Volcano Fissure 8 captured on May 3rd, 2019

Two views of Halemaʻumaʻu from roughly the same vantage point. At left is the view from 2008, with a distinct gas plume from the Overlook vent, the location of what would become a long-lived lava lake. At right is a view of Halemaʻumaʻu after the eruptive events of 2018, showing the collapsed crater.

View of the eruption from outside the summit caldera, on December 20, 2020

Ōhia (Metrosideros polymorpha) growing on a barren lava field dating from 1986, formerly the village of Kalapana, Hawaii. The myrtle in this picture, taken in 2009, may have since been covered over—fresh flows in 2010 partially re-covered the area.

The 'amakihi (Chlorodrepanis virens) is one of the many birds that live on the volcano's flanks.

A view from Kīlauea's eastern rift zone captured during a USGS expedition.

View from the edge of Kilauea Iki: across the caldera, Halemaʻumaʻu is emitting fume on the left side of the caldera, while Mauna Loa towers above in the background

Kīlauea is an active shield volcano in the Hawaiian Islands.

Historically, it is the most active of the five volcanoes that together form Hawaii island.

Caldera

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Large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcanic eruption.

Animation of analogue experiment showing the origin of the volcanic caldera in box filled with flour.

Landsat image of Lake Toba, on the island of Sumatra, Indonesia (100 km/62 mi long and 30 km/19 mi wide, one of the world's largest calderas). A resurgent dome formed the island of Samosir.

Satellite photograph of the summit caldera on Fernandina Island in the Galápagos archipelago.

Oblique aerial photo of Nemrut Caldera, Van Lake, Eastern Turkey

Sollipulli Caldera, located in central Chile near the border with Argentina, filled with ice. The volcano is in the southern Andes Mountains within Chile's Parque Nacional Villarica.

A collapse is triggered by the emptying of the magma chamber beneath the volcano, sometimes as the result of a large explosive volcanic eruption (see Tambora in 1815), but also during effusive eruptions on the flanks of a volcano (see Piton de la Fournaise in 2007) or in a connected fissure system (see Bárðarbunga in 2014–2015).

Some volcanoes, such as the large shield volcanoes Kīlauea and Mauna Loa on the island of Hawaii, form calderas in a different fashion.

Lava

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Molten or partially molten rock that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon onto its surface.

Lava flow during a rift eruption at Krafla, Iceland in 1984

Pāhoehoe and ʻaʻā lava flows side by side in Hawaii, September 2007

Toes of a pāhoehoe advance across a road in Kalapana on the east rift zone of Kīlauea Volcano in Hawaii, United States

Columnar jointing in Giant's Causeway in Northern Ireland

Lava entering the sea to expand the big island of Hawaii, Hawaii Volcanoes National Park

Lava enters the Pacific at the Big Island of Hawaii

Glowing aā flow front advancing over pāhoehoe on the coastal plain of Kilauea in Hawaii, United States

Pāhoehoe lava from Kīlauea volcano, Hawaii, United States

Block lava at Fantastic Lava Beds near Cinder Cone in Lassen Volcanic National Park

Pillow lava on the ocean floor near Hawaii

Arenal Volcano, Costa Rica, is a stratovolcano.

A forested lava dome in the midst of the Valle Grande, the largest meadow in the Valles Caldera National Preserve, New Mexico, United States

Shiprock, New Mexico, United States: a volcanic neck in the distance, with a radiating dike on its south side

Lava can easily destroy entire towns. This picture shows one of over 100 houses destroyed by the lava flow in Kalapana, Hawaii, United States, in 1990.

Lava may be erupted at a volcano or through a fracture in the crust, on land or underwater, usually at temperatures from 800 to 1200 C. The volcanic rock resulting from subsequent cooling is also often called lava.

Mafic lavas tend to produce low-profile shield volcanoes or flood basalts, because the less viscous lava can flow for long distances from the vent.

Olympus Mons

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Colorized topographic map of Olympus Mons and its surrounding aureole, from the MOLA instrument of Mars Global Surveyor.

Olympus Rupes, the northern part of Olympus Mons.

Mars Global Surveyor image showing lava flows of different ages at the base of Olympus Mons. The flat plain is the younger flow. The older flow has lava channels with levees along the edges. Levees are quite common to lava flows on Mars.

Lava flows on Olympus Mons with older and younger flows labeled, as viewed by HiRISE during the HiWish program.

Calderas on the summit of Olympus Mons. The youngest calderas form circular collapse craters. Older calderas appear as semicircular segments because they are transected by the younger calderas.

Oblique view of Olympus Mons, from a Viking image mosaic overlain on MOLA altimetry data, showing the volcano's asymmetry. The view is from the NNE; vertical exaggeration is 10×. The wider, gently sloping northern flank is to the right. The more narrow and steeply sloping southern flank (left) has low, rounded terraces, features interpreted as thrust faults. The volcano's basal escarpment is prominent.

Detailed THEMIS daytime infrared image mosaic of Olympus Mons.

Olympus Mons (Latin for Mount Olympus) is a large shield volcano on Mars.

It is the largest and highest mountain and volcano of the Solar System, and is associated with the Tharsis Montes, a large volcanic region on Mars.

Mauna Loa

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One of five volcanoes that form the Island of Hawaii in the U.S. state of Hawaiʻi in the Pacific Ocean.

Snow-covered Moku‘aweoweo caldera in 2016

A view of Mauna Loa taken from a hill near The Onizuka Center for International Astronomy Visitor Information Station at the 9,300 ft. level of Mauna Kea.

A cinder cone and surrounding flows on Mauna Loa

Lava fountains and a'a channel flow from Mauna Loa, 1984

The Scottish botanist and naturalist Archibald Menzies was the first European to reach the summit of Mauna Loa, on his third attempt.

Sketch of Wilkes' campsite by ship's artist Alfred Thomas Agate

Sketch of Mokuʻāweoweo from Wilkes' journal

Atmospheric CO2 concentrations measured at the Mauna Loa Observatory.

It is an active shield volcano with relatively gentle slopes, with a volume estimated at 18000 mi3, although its peak is about 125 ft lower than that of its neighbor, Mauna Kea.

Magma

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Molten or semi-molten natural material from which all igneous rocks are formed.

Phase diagram for the diopside-anorthite system

$Schematic diagrams showing the principles behind fractional crystallisation in a magma. While cooling, the magma evolves in composition because different minerals crystallize from the melt. 1: olivine crystallizes; 2: olivine and pyroxene crystallize; 3: pyroxene and plagioclase crystallize; 4: plagioclase crystallizes. At the bottom of the magma reservoir, a cumulate rock forms.$

Two silica tetrahedra joined by a bridging oxygen ion (tinted pink)

Following its ascent through the crust, magma may feed a volcano and be extruded as lava, or it may solidify underground to form an intrusion, such as a dike, a sill, a laccolith, a pluton, or a batholith.

Basalt lavas tend to produce low-profile shield volcanoes or flood basalts, because the fluidal lava flows for long distances from the vent.

Mars

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Fourth planet from the Sun and the second-smallest planet in the Solar System, being larger than only Mercury.

A cross-section of underground water ice is exposed at the steep slope that appears bright blue in this enhanced-color view from the MRO. The scene is about 500 meters wide. The scarp drops about 128 meters from the level ground. The ice sheets extend from just below the surface to a depth of 100 meters or more.

A MOLA-based topographic map showing highlands (red and orange) dominating the Southern Hemisphere of Mars, lowlands (blue) the northern. Volcanic plateaus delimit regions of the northern plains, whereas the highlands are punctuated by several large impact basins.

Fresh asteroid impact on Mars at 3.34°N, 219.38°W. These before and after images of the same site were taken on the Martian afternoons of 27 and 28 March 2012 respectively (MRO).

Viking 1 image of Olympus Mons. The volcano and related terrain are approximately 550 km across.

Escaping atmosphere on Mars (carbon, oxygen, and hydrogen) by MAVEN in UV

Mars is about 143 e6mi from the Sun; its orbital period is 687 (Earth) days, depicted in red. Earth's orbit is in blue.

Viking 1 lander's sampling arm scooped up soil samples for tests (Chryse Planitia)

The descent stage of the Mars Science Laboratory mission carrying the Curiosity rover deploys its parachutes to decelerate itself before landing, photographed by Mars Reconnaissance Orbiter.

Animation of the apparent retrograde motion of Mars in 2003 as seen from Earth.

Mars distance from Earth in millions of km (Gm).

Martian tripod illustration from the 1906 French edition of The War of the Worlds by H. G. Wells

Curiosity view of Martian soil and boulders after crossing the "Dingo Gap" sand dune

Valles Marineris, taken by the Viking 1 probe

Edge-on view of Mars atmosphere by Viking 1 probe

Orbit of Mars and other Inner Solar System planets

Curiosity’s robotic arm showing drill in place, February 2013

Scoop of Mars soil by Curiosity, October 2012

Ingenuity helicopter on Mars, preparing for its first flight

Mars seen through an 16-inch amateur telescope, at 2020 opposition

Some of the most notable surface features on Mars include Olympus Mons, the largest volcano and highest known mountain on any planet in the Solar System, and Valles Marineris, one of the largest canyons in the Solar System.

The shield volcano Olympus Mons (Mount Olympus) is an extinct volcano in the vast upland region Tharsis, which contains several other large volcanoes.

Galileo spacecraft true-color image of Io. The dark spot just left of the center is the erupting volcano Prometheus. The whitish plains on either side of it are coated with volcanically deposited sulfur dioxide frost, whereas the yellower regions contain a higher proportion of sulfur.

Io (moon)

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Innermost and third-largest of the four Galilean moons of the planet Jupiter.

Size comparison between Io (lower left), the Moon (upper left) and Earth

Voyager 1 mosaic covering Io's south polar region. This includes two of Io's ten highest peaks, the Euboea Montes at upper extreme left and Haemus Mons at bottom.

Enhanced-color Galileo image showing a dark spot (just lower-left of center, interrupting the red ring of short-chain sulfur allotropes deposited by Pele) produced by a major eruption at Pillan Patera in 1997

The Cassini-Huygens mission's view of Io and Jupiter on January 1, 2001

Animation of the Laplace resonance of Io, Europa and Ganymede (conjunctions are highlighted by color changes)

Schematic of Jupiter's magnetosphere and the components influenced by Io (near the center of the image): the plasma torus (in red), the neutral cloud (in yellow), the flux tube (in green), and magnetic field lines (in blue).

The Jupiter - Io System and Interaction
(artwork; 15 July 2021)

Model of the possible interior composition of Io with various features labelled.

Active lava flows in volcanic region Tvashtar Paterae (blank region represents saturated areas in the original data). Images taken by Galileo in November 1999 and February 2000.

Five-image sequence of New Horizons images showing Io's volcano Tvashtar spewing material 330 km above its surface

Galileo greyscale image of Tohil Mons, a 5.4-km-tall mountain

Auroral glows in Io's upper atmosphere. Different colors represent emission from different components of the atmosphere (green comes from emitting sodium, red from emitting oxygen, and blue from emitting volcanic gases like sulfur dioxide). Image taken while Io was in eclipse.

With over 400 active volcanoes, Io is the most geologically active object in the Solar System.

Unlike similar features on Earth and Mars, these depressions generally do not lie at the peak of shield volcanoes and are normally larger, with an average diameter of 41 km, the largest being Loki Patera at 202 km. Loki is also consistently the strongest volcano on Io, contributing on average 25% of Io's global heat output.