A report on Volcano and Magma

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.

Lava flow on Hawaii. Lava is the extrusive equivalent of magma.

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).

Phase diagram for the diopside-anorthite system

Sabancaya volcano erupting, Peru in 2017

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

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

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

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

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

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

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

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.

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

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.

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.

- Magma

In a process called flux melting, water released from the subducting plate lowers the melting temperature of the overlying mantle wedge, thus creating magma.

- Volcano

14 related topics with Alpha

Lava

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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 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 800 to 1200 C. The volcanic rock resulting from subsequent cooling is also often called lava.

Simplified map of Earth's principal tectonic plates, which were mapped in the second half of the 20th century (red arrows indicate direction of movement at plate boundaries)

Plate tectonics

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Generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large tectonic plates which have been slowly moving since about 3.4 billion years ago.

Diagram of the internal layering of Earth showing the lithosphere above the asthenosphere (not to scale)

Plate motion based on Global Positioning System (GPS) satellite data from NASA JPL. Each red dot is a measuring point and vectors show direction and magnitude of motion.

Detailed map showing the tectonic plates with their movement vectors.

Alfred Wegener in Greenland in the winter of 1912–13.

Global earthquake epicenters, 1963–1998. Most earthquakes occur in narrow belts that correspond to the locations of lithospheric plate boundaries.

A demonstration of magnetic striping. (The darker the color is, the closer it is to normal polarity)

Earthquakes, volcanic activity, mountain-building, and oceanic trench formation occur along these plate boundaries (or faults).

New magma from deep within Earth rises easily through these weak zones and eventually erupts along the crest of the ridges to create new oceanic crust.

Igneous rock

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One of the three main rock types, the others being sedimentary and metamorphic.

Natural columns of igneous rock separated from each other by columnar joints, in Madeira

Extrusive igneous rock is made from lava released by volcanoes

Sample of basalt (an extrusive igneous rock), found in Massachusetts

Close-up of granite (an intrusive igneous rock) exposed in Chennai, India

Gabbro specimen showing phaneritic texture, from Rock Creek Canyon, eastern Sierra Nevada, California

$Basic classification scheme for igneous rocks based on their mineral composition. If the approximate volume fractions of minerals in the rock are known, the rock name and silica content can be read off the diagram. This is not an exact method, because the classification of igneous rocks also depends on other components, yet in most cases it is a good first guess.$

Total alkali versus silica classification scheme (TAS) as proposed in Le Maitre's 2002 Igneous Rocks – A classification and glossary of terms Blue area is roughly where alkaline rocks plot; yellow area is where subalkaline rocks plot.

AFM ternary diagram showing the relative proportions of Na2O + K2O (A for Alkali earth metals), FeO + Fe2O3 (F), and MgO (M) with arrows showing the path of chemical variation in tholeiitic and calc-alkaline series magmas

Kanaga volcano in the Aleutian Islands with a 1906 lava flow in the foreground

A "skylight" hole, about {{cvt|6|m}} across, in a solidified lava crust reveals molten lava below (flowing towards the top right) in an eruption of Kīlauea in Hawaii

Devils Tower, an eroded laccolith in the Black Hills of Wyoming

A cascade of molten lava flowing into Aloi Crater during the 1969-1971 Mauna Ulu eruption of Kilauea volcano

Columnar jointing in the Alcantara Gorge, Sicily

A laccolith of granite (light-coloured) that was intruded into older sedimentary rocks (dark-coloured) at Cuernos del Paine, Torres del Paine National Park, Chile

An igneous intrusion cut by a pegmatite dike, which in turn is cut by a dolerite dike

Igneous rock is formed through the cooling and solidification of magma or lava.

Eruptions of volcanoes into air are termed subaerial, whereas those occurring underneath the ocean are termed submarine.

Carbonatite

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Type of intrusive or extrusive igneous rock defined by mineralogic composition consisting of greater than 50% carbonate minerals.

Carbonatite lava at Ol Doinyo Lengai volcano, Tanzania

Magnesiocarbonatite, from Verity-Paradise Carbonatite Complex of British Columbia. Specimen is 75 mm wide.

Okaite, an ultramafic rock found near the carbonatite of the Oka Carbonatite Complex, Oka, Quebec

Thin section of apatite-rich carbonatite in cross polarised transmitted light. The sample is from Siilinjärvi apatite mine.

Only one carbonatite volcano is known to have erupted in historical time, the active Ol Doinyo Lengai volcano in Tanzania.

It was however the 1960 eruption of Ol Doinyo Lengai in Tanzania that led to geological investigations that finally confirmed the view that carbonatite is derived from magma.

A Jurassic pluton of pink monzonite intruded below a section of gray sedimentary rocks which was subsequently uplifted and exposed, near Notch Peak, House Range, Utah.

Igneous intrusion

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The exposed laccolith atop a massive pluton system near Sofia, formed by the Vitosha syenite and Plana diorite domed mountains and later uplifted

Basic types of intrusions: 1. Laccolith, 2. Small dike, 3. Batholith, 4. Dike, 5. Sill, 6. Volcanic neck, pipe, 7. Lopolith.

Thermal profiles at different times after intrusion, illustrating square root law

In geology, an igneous intrusion (or intrusive body or simply intrusion ) is a body of intrusive igneous rock that forms by crystallization of magma slowly cooling below the surface of the Earth.

Volcanic necks are feeder pipes for volcanoes that have been exposed by erosion.

Diagram showing a cross section through the Earth's lithosphere (in yellow) with magma rising from the mantle (in red). Lower diagram illustrates a hotspot track caused by the lithosphere's movement.

Hotspot (geology)

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Schematic diagram showing the physical processes inside the Earth that lead to the generation of magma. Partial melting begins above the fusion point.

Over millions of years, the Pacific Plate has moved over the Hawaii hotspot, creating a trail of underwater mountains that stretches across the Pacific

Kilauea is the most active shield volcano in the world. The volcano erupted nonstop from 1983 to 2018 and it is part of the Hawaiian–Emperor seamount chain.

Mauna Loa is a large shield volcano. Its last eruption was in 1984 and it is part of the Hawaiian–Emperor seamount chain.

Bowie Seamount is a dormant submarine volcano and it is part of the Kodiak-Bowie Seamount chain.

Axial Seamount is the youngest seamount of the Cobb–Eickelberg Seamount chain. Its last eruption was on 6 April 2011.

Mauna Kea is the tallest volcano in the Hawaiian–Emperor seamount chain. It is dormant and it has cinder cones growing on the volcano.

Hualalai is a massive shield volcano in the Hawaiian–Emperor seamount chain. Its last eruption was in 1801.

An example of mantle plume locations suggested by one recent group. Figure from Foulger (2010).

Distribution of hotspots in the list to the left, with the numbers corresponding to those in the list. The Afar hotspot (29) is misplaced.

Over millions of years, the Pacific Plate has moved over the Bowie hotspot, creating the Kodiak-Bowie Seamount chain in the Gulf of Alaska

In geology, hotspots (or hot spots) are volcanic locales thought to be fed by underlying mantle that is anomalously hot compared with the surrounding mantle.

Where hotspots occur in continental regions, basaltic magma rises through the continental crust, which melts to form rhyolites.

Magma chamber

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Large pool of liquid rock beneath the surface of the Earth.

The molten rock, or magma, in such a chamber is less dense than the surrounding country rock, which produces buoyant forces on the magma that tend to drive it upwards.

If the magma finds a path to the surface, then the result will be a volcanic eruption; consequently, many volcanoes are situated over magma chambers.

Komatiite

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Type of ultramafic mantle-derived volcanic rock defined as having crystallised from a lava of at least 18 wt% MgO.

Komatiite sample collected from the Abitibi greenstone belt near Englehart, Ontario, Canada. Specimen is 9 cm wide. Bladed olivine crystals are visible, though spinifex texture is weak or absent in this sample.

Graph of komatiite geochemistry MgO% vs Cr ppm, from basal flows, Wannaway, Western Australia

Photomicrograph of a thin section of komatiite showing spinifex texture of pyroxene needle-like crystals

A2 facies dendritic feathery olivine crystals, drill hole WDD18, Widgiemooltha, Western Australia

A3 facies bladed olivine spinifex, drill hole WDD18, Widgiemooltha Komatiite, Western Australia

Magmas of komatiitic compositions have a very high melting point, with calculated eruption temperatures up to, and possibly in excess of 1600 °C.

Komatiite volcano morphology is interpreted to have the general form and structure of a shield volcano, typical of most large basalt edifices, as the magmatic event which forms komatiites erupts less magnesian materials.

Pillow lava

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Pillow lavas are lavas that contain characteristic pillow-shaped structures that are attributed to the extrusion of the lava underwater, or subaqueous extrusion.

Weathered Archean pillow lava in the Temagami Greenstone Belt of the Canadian Shield

Pillow lava formations from an ophiolite sequence, Northern Apennines, Italy

Pillow lava at Boatman's Harbour near Oamaru, New Zealand.

They occur wherever lava is extruded underwater, such as along marine hotspot volcano chains and the constructive plate boundaries of mid-ocean ridges.

They are created when magma reaches the surface but, as there is a large difference in temperature between the lava and the water, the surface of the emergent tongue cools very quickly, forming a skin.

Lava dome

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One of the Inyo Craters, an example of a rhyolite dome

Lava domes in the crater of Mount St. Helens

The bulging cryptodome of Mt. St. Helens on April 27, 1980

Soufrière Hills lava spine before the 1997 eruption

Chao dacite coulée flow-domes (left center), northern Chile, viewed from Landsat 8

In volcanology, a lava dome is a circular mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano.

This high viscosity can be obtained in two ways: by high levels of silica in the magma, or by degassing of fluid magma.