Volcanism

The decrease of pressure in the rising mantle rock leads to adiabatic expansion and the partial melting of the rock, causing volcanism and creating new oceanic crust.

Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption.

Scoria (pl. scoriae), also called volcanic cinder, is a pyroclastic, highly vesicular, dark-colored volcanic rock formed by ejection from a volcano as a molten blob and cooled in the air to form discrete grains called clasts.

Stratovolcano, Compound Guatemala, 15.04°N / -91.9°W

Shield, Stratovolcano(es), Pyroclastic cone(s) Kyushu (Japan), 31.93°N / 130.86°E

Shield, Pyroclastic cone(s), Lava dome(s) Antarctica, -77.52°S / 168.55°E

Stratovolcano, Lava dome(s)

Lava dome, Tuff cone Mindanao (Philippines), 7.88°N / 125.07°E

Instead, archipelagic aprons most likely formed from debris avalanches and pyroclastic flows.

Formed by volcanic activity, the islands are covered by rainforest and surrounded by coral reef formations, which provide habitat and breeding areas for hawksbill turtle, green turtle and the dugong.

Sulfur compound aerosols derived from volcanic eruptions have been found to be the source for the Bishop's Ring effect.

A lava field, sometimes called a lava bed, is a large, mostly flat area of lava flows.

Penghu is the remnant of a Miocene-age shield volcano.

The eastern islands of the archipelago are part of the Luzon Volcanic Arc.

indicating the presence of a long-lived dynamic lake system punctuated by catastrophic volcanism

The site is dominated by volcanic tuff, limestone, and silica deposits of large freshwater lakes associated with hot springs and local basaltic (high-iron) volcanism.

Acatenango is a stratovolcano in Guatemala, close to the city of Antigua.

Aconcagua was formed by the subduction of the Nazca Plate beneath the South American Plate and was once an active stratovolcano, before tectonic shifts during the Miocene halted volcanic activity.

The Algar do Carvão (Cavern of Coal) is an ancient lava tube or volcanic vent located in the central part of the island of Terceira in the Portuguese archipelago of the Azores.

The Andagua volcanic field (also known as Andahua) is a volcanic field in southern Peru which includes a number of cinder cones, lava domes and lava flows which have filled the Andagua Valley (which is also known as Valley of the Volcanoes for this reason).

Next to the Pichincha, Cotopaxi, Tungurahua and Chimborazo, the Antisana belongs to the five volcanic mountains that the Prussian-born explorer Alexander von Humboldt tried to climb in 1802 during his American journey.

Cerro Tuzgle (Spanish pronunciation: [ˈse.ro ˈtus.ɡle]) is a dormant stratovolcano in the Susques Department of Jujuy Province in northwestern Argentina. Tuzgle is a prominent volcano of the back arc of the Andes and lies about 280 kilometres (170 mi) east of the main volcanic arc.

Chachani is a volcanic group in southern Peru, 22 kilometres (14 mi) northwest of the city of Arequipa.

Located approximately 36 miles (58 km) southeast of Willcox, Arizona, the monument preserves the remains of an immense volcanic eruption that shook the region about 27 million years ago.

The Corbetti Caldera is 15 km (9.3 mi) across and overlaps an older (pleistocene), 30 by 40 km (19 by 25 mi) caldera called Awasa, which is considered the same volcanic system.

These are composed chiefly of ignimbrites and lava flows on a basement formed by Middle Miocene ignimbrites and lava flows.

These formations were created by strong erosion of the soil that was scene of intense volcanic activity millions of years ago.

They are one of the largest volcanic features on Earth, with lava erupted from multiple volcanic centres.

Deception Island is the exposed portion of an active shield volcano 30 km in diameter.

It was formerly an island of volcanic origin, which is also known by the Icelandic word eyja [ˈeiːja] meaning island.

A massive, mainly snow-covered mountain 4,285 metres (14,058 ft) high, which is the highest and most imposing of the five extinct volcanic mountains that comprise the Executive Committee Range.

Falso Azufre is part of the Central Volcanic Zone of the Andes together with about 110 other Quaternary volcanoes, and lies in the southern sector of the volcanic zone; other volcanic zones in the Andes are the Northern Volcanic Zone, the Southern Volcanic Zone and the Austral Volcanic Zone.

It consists of 21 islands, islets and rocks of volcanic origin.

The Giant's Causeway (Irish: Clochán an Aifir or Clochán na bhFomhórach) is an area of approximately 40,000 interlocking basalt columns, the result of an ancient volcanic fissure eruption, part of the North Atlantic Igneous Province active in the region during the Paleogene period.

Its underlying strata were formed by Pliocene and Pleistocene lava flows covered by Holocene sedimentary deposits.

From about 10 to 18 million years ago, a series of volcanic eruptions from the Grand Ronde Rift near the Idaho/Oregon/Washington/Montana border began to fill the inland sea with lava.

Les Saintes is a volcanic archipelago fully encircled by shallow reefs.

Incahuasi (Spanish pronunciation: [iŋkaˈwasi]; possibly from Quechua: inka Inca, wasi house) is a volcanic mountain in the Andes of South America.

Oceanic islands can be formed from volcanic activity, grow into atolls from coral reefs, and form from sediment along shorelines, creating barrier islands.

Iztaccíhuatl or Ixtaccíhuatl (both forms also spelled without the accent) (Nahuatl pronunciation: [istakˈsiwat͡ɬ] or, as spelled with the x, [iʃtakˈsiwat͡ɬ]) is a 5,230 m (17,160 ft) dormant volcanic mountain in Mexico located on the border between the State of Mexico and Puebla within Izta-Popo Zoquiapan National Park.

The Kamenice Gorge was formed in the Tertiary period when the sea receded and volcanic activity caused the sandstone layers to break into many pieces.

It has three volcanic crater lakes that differ in color.

to erupt, but at the Lassen locus, the Maidu and Dittmar volcanic centers overlapped during the late Pliocene to the early Pleistocene. Volcanism within the Lassen vicinity follows a trend of intermittent, episodic eruptions punctuating long periods of dormancy, a pattern which persisted through the late Pleistocene and

Most of the islands are part of a long, partially volcanic island arc between the Greater Antilles and the continent of South America.

Licancabur formed on top of ignimbrites produced by other volcanoes, and has been active during the Holocene.

Masaya is one of 18 distinct volcanic centers that make up the Nicaraguan portion of the Central American Volcanic Belt (CAVF).

The lower half, from Koblenz (Rhine-kilometer 593) to Bonn (Rhine-kilometer 655), is famous for the formerly volcanic Siebengebirge, with the Drachenfels volcano.

Due to the differences in the environment and stratigraphy, more recent authors have also called these sites the Bolca Lagerstätten. Due to volcanic events that had taken place in the area, a number of tectonic disturbances are present which were a result of the uplift of the ‘‘Trento Plateau’’.

Monte Pissis is a large andesitic-dacitic volcanic centre.

Morro Rock (Salinan: Le'samo; Chumash: Lisamu'; Spanish: El Morro) is a volcanic plug in Morro Bay, California, the Pacific Coast at the entrance to Morro Bay harbor.

The mountain is built up from non-alkali mafic and pyroclastic volcanic rocks dating from the Late Pleistocene to the Holocene.

Four large-scale eruptions (Aso 1-4) occurred during a period extending from 300,000 to 90,000 years ago. As large amounts of pyroclastic flow and volcanic ash were emitted from the volcanic chamber, a huge depression (caldera) was formed as the chamber collapsed.

It is thought that volcanic activity began about 290,000 years ago when there were two scoria eruptions, after the activity of Mount Nekoma (from approximately 1.1 million years ago to 350 thousand years ago) somewhere to the west.

The volcano began erupting during the Pliocene and was active into the late Pleistocene and the Holocene.

The mountain is part of the area of volcanic activity known as the Cameroon Volcanic Line, which also includes Lake Nyos, the site of a disaster in 1986.

The peak is a 439 metres high intrusive volcanic plug and is the highest point and main feature of the Tuchekoi National Park.

Mount Discovery (78°22′S 165°01′E) is a conspicuous, isolated volcanic cone, 2,680 metres (8,790 ft) high, lying at the head of McMurdo Sound and east of Koettlitz Glacier, overlooking the northwest portion of the Ross Ice Shelf.

Although there is no verifiable evidence of its earliest volcanic activity, geologists estimate that Mount Elgon is at least 24 million years old, making it the oldest known extinct volcano in East Africa.

Isarog Volcano is interpreted to have formed during the Pleistocene, as indicated by K-Ar dating of lava samples from the edifice, which yielded an age of 0.16 ± 0.12 Ma.

Mount Kenya is a stratovolcano that was active in the Plio-Pleistocene.

One of several mountains arising from the East African Rift, Kilimanjaro was formed from volcanic activity over two million years ago.

The forest on top, within a volcanic crater, covers only about 30 hectares (74 acres).

The least studied mountain range was formed through several volcanic activities some of which could be historical, evident by the presence of two calderas, surrounded by high rock walls, cinder cones, dome volcano plugs, two sulfurous hot springs, and a crater lake named Lake Duminagat.

This was primarily built during the Miocene, but some lava flows and explosive maar-forming eruptions have occurred more recently.

The volcanic group consists of large shield volcanoes mainly near the coast, stratovolcanoes and monogenetic volcanoes which formed parallel to the Transantarctic Mountains. Volcanic activity of the McMurdo Volcanic Group is tied to continental rifting and commenced during the Oligocene.

Nyiragongo and nearby Nyamuragira are together responsible for 40% of Africa's historical volcanic eruptions.

The summit is topped by two volcanic craters, each more than 1,000 ft (300 m) in diameter, with the larger east crater overlapping the west crater.

No major air routes or supply roads to Antarctic stations pass close to the mountain, and some parts of the cone are accessible only by helicopter. The volcanic mountain rises 2,100 metres (6,900 ft) above the ice level with maximum elevation 3,460 metres (11,350 ft).

Mount Unzen (雲仙岳, Unzen-dake; Japanese pronunciation: [ɯ̈́ǹ.d͡zè̞ɴ̀, ɯ̈̀ń.d͡zé̞ǹ.dä̀.kè̞, ɯ̈́ń.d͡zé̞ǹ-]) is an active stratovolcano of several overlapping small, volcanic cones, near the city of Shimabara, Nagasaki on the island of Kyushu, Japan's southernmost main island.

It is one of several volcanoes forming the Campanian volcanic arc.

It is a stratovolcano composed of many layers of lava alternating with hardened volcanic ash and other pyroclastic rocks. Volcanic activity at Nevado del Ruiz began about two million years ago, during the Early Pleistocene or Late Pliocene, with three major eruptive periods.

The Nevado del Tolima is a Late Pleistocene to recently active andesitic stratovolcano located in the Tolima department, Colombia.

Nevado Tres Cruces is a massif of volcanic origin in the Andes Mountains on the border of Argentina and Chile.

The area is named after Ngorongoro Crater, a large volcanic caldera within the area.

Ojos del Salado was volcanically active during the Pleistocene and Holocene, during which it mainly produced lava flows.

It consists of a volcanic cone with two craters, the northern of which has erupted during historical time.

It is the most southern of the volcanoes in the Öræfi volcanic belt (Öræfajökull volcanic belt), which is possibly an embryonic rift parallel and to the east of the Eastern volcanic zone.

The basin includes six maar lakes, locally called axalpazcos, lying in shallow volcanic craters and sustained by underground water.

Pacaya lies on the southern edge of a sizable volcanic caldera formed in the Pleistocene age which contains Lago de Amatitlán.

By 1952, the eruption had left a 424-meter-high (1,391 ft) cone and significantly damaged an area of more than 233 square kilometers (90 mi2) with the ejection of stone, volcanic ash and lava.

The rock formations have their origin during the Cenozoic era about 66 million years ago with volcanic activity.

The Pinacate Peaks (Sierra Pinacate) are a group of volcanic peaks and cinder cones located mostly in the Mexican state of Sonora along the international border adjacent to the U.S. state of Arizona, surrounded by the vast sand dune field of the Gran Desierto de Altar, at the desert's southeast.

These form a section of the active volcanic arc of the Lesser Antilles.

It was formed by a volcanic eruption around 4.5 million years ago.

San Cristóbal is part of a 5-member volcanic complex that bears the same name.

Shiprock, an example of a volcanic neck, is composed of fractured volcanic breccia and black dikes of igneous rock called minette, a type of lamprophyre.

The dramatic views are due to this volcanic activity.

The Deccan Traps that formed during Cretaceous-Eocene time about 60 million years ago emerged from the vast deluge of hot molten basaltic lava in the western part of India which is now seen as flat topped hills and step like terraces.

Within Organ Pipes National Park, the valley walls of Jacksons Creek expose Pleistocene volcanic rocks of the New Volcanic Group.

Þingvellir is notable for its unusual tectonic and volcanic environment in a rift valley.

The volcanic activity was the result of a continental hotspot that arose during the Oligocene and continued in some places until the Holocene, creating fumaroles, hot springs, mud pools and deposits of natron and sulfur.

The valley is part of the Trans-Mexican Volcanic Belt, with its soils of volcanic origin mostly dating from the Upper Cenozoic.

Tunkin Depression is a volcanic field in Russia.

Ubehebe Crater ( yoo-bee-HEE-bee) is a large volcanic crater of the Ubehebe Craters volcanic field in the northern half of Death Valley, in Death Valley National Park, California, United States.

Most prevalent though are the Quaternary stratovolcanoes along the Aleutian Arc associated with the Aleutian subduction zone.

The Waimangu Volcanic Rift Valley is the hydrothermal system created on 10 June 1886 by the volcanic eruption of Mount Tarawera, on the North Island of New Zealand.

It has been described as a volcanic plug by geographers.

Hematite can also occur in the absence of water, usually as the result of volcanic activity.

Feldspars crystallize from magma as both intrusive and extrusive igneous rocks

It typically crystallizes in granitic pegmatites or in vapor cavities in rhyolite lava flows

Agates are most commonly found as nodules within volcanic rocks.

Momotombo is a stratovolcano in Nicaragua, located near the city of León

The Barrier is a lava dam retaining the Garibaldi Lake system in southwestern British Columbia, Canada

Mauna Loa (, Hawaiian: [ˈmɐwnə ˈlowə]; lit. 'Long Mountain') is one of five volcanoes that form the Island of Hawaii in the U.S. state of Hawaii in the Pacific Ocean

Mount Rinjani (Indonesian: Gunung Rinjani; Sasak: ᬕᬸᬦ᭄ᬗᬸᬂ᭞ᬭᬶᬦ᭄ᬚᬦᬶ, romanized: gunong rinjani) is an active stratovolcano situated in regencial North Lombok of West Nusa Tenggara province on the Indonesian island of Lombok

A mud volcano or mud dome is a landform created by the eruption of mud or slurries, water and gases

In geology and geomorphology, an erosion surface is a surface of rock or regolith that was formed by erosion and not by construction (e.g. lava flows, sediment deposition) nor fault displacement

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

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

A stratovolcano, also known as a composite volcano, is a typically conical volcano built up by many alternating layers (strata) of hardened lava and tephra

A tuya is a flat-topped, steep-sided volcano formed when lava erupts through a thick glacier or ice sheet

Submarine volcanoes are underwater vents or fissures in the Earth's surface from which magma can erupt

A cryovolcano (sometimes informally referred to as an ice volcano) is a type of volcano that erupts gases and volatile material such as liquid water, ammonia, and hydrocarbons

A hornito is a conical, or pipe-like, structure built up by lava spattering or being ejected through an opening in the crust of a lava flow

Meola Reef, officlally Te Tokaroa Reef ('toka'='rock', 'roa'='long'), is a lava flow forming a reef peninsula across part of Auckland's Waitemata Harbour, New Zealand

Basalt (UK: BAH-salt); US: buh-SALT) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon

Andesite () is a volcanic rock of intermediate composition

Rhyolite ( RY-ə-lyte) is the most silica-rich of volcanic rocks

Dacite () is a volcanic rock formed by rapid solidification of lava that is high in silica and low in alkali metal oxides

The Minoan eruption was a catastrophic volcanic eruption that devastated the Aegean island of Thera (also called Santorini) circa 1600 BC. It destroyed the Minoan settlement at Akrotiri, as well as communities and agricultural areas on nearby islands and the coast of Crete with subsequent earthquakes and tsunamis.

The Toba eruption (also called the Toba supereruption and the Youngest Toba eruption) was a large eruption that occurred around 74,000 years ago, during the Late Pleistocene, at the site of present-day Lake Toba, in Sumatra, Indonesia.

Between March and June 2010 a series of volcanic events at Eyjafjallajökull in Iceland caused enormous disruption to air travel across Western Europe.

The 1991 Eruption of Mount Unzen (Japanese: 1991年の雲仙岳噴火) was a natural disaster caused by the eruption of Mount Unzen in Nagasaki Prefecture, Japan.

In December 2021, an eruption began on Hunga Tonga-Hunga Haʻapai, a submarine volcano in the Tongan archipelago in the southern Pacific Ocean.

The volcanic winter was caused by at least three eruptions of uncertain origin, with several possible locations proposed in various continents.

Popocatépetl (UK: POP-ə-KAT-ə-pet-əl, -⁠kat-ə-PET-əl, US: POHP-, Spanish: [popokaˈtepetl] ; Nahuatl languages: Popōcatepētl [popoːkaˈtepeːt͡ɬ] ) is an active stratovolcano located in the states of Puebla, Morelos, and Mexico in central Mexico.

Rincón de la Vieja is an active andesitic complex volcano in north-western Costa Rica, about 23 km (14 mi) from Liberia, in the province of Guanacaste.

Menengai Crater is a massive shield volcano with one of the biggest calderas in the world, in the Great Rift Valley, Kenya.

Mount Hibok-Hibok (also known as Catarman Volcano) is a stratovolcano on Camiguin Island in the Philippines.

Cosigüina (also spelt Cosegüina) is a stratovolcano located in the western part of Nicaragua.

Santa María Volcano is a large active volcano in the western highlands of Guatemala, in the Quetzaltenango Department near the city of Quetzaltenango.

Mount Iraya, is an active stratovolcano on Batan Island, and is the highest point in the province of Batanes, Philippines.

Sierra Negra (Spanish: Black Mountain) is a large shield volcano at the southeastern end of Isabela Island in the Galapagos that rises to an altitude of 1124m.

Torfajökull (Icelandic for "Torfi's glacier"; Icelandic pronunciation: [ˈtʰɔrvaˌjœːkʏtl̥] ) is a rhyolitic stratovolcano, with a large caldera (central volcano) capped by a glacier of the same name and associated with a complex of subglacial volcanoes.

They cover an area of 27.8 km2 or 10.7 sq mi, and are made up of the Mangareva Islands, a group of high islands remnants of a caldera along with islets on the surrounding fringing reef, and the uninhabited Temoe atoll, which is located 45 km (28 mi) south-east of the Mangareva Islands.

Geological studies indicate the rock is the exposed core of an ancient volcano.

A kīpuka is an area of land surrounded by one or more younger lava flows.

Seamounts are typically formed from extinct volcanoes that rise abruptly and are usually found rising from the seafloor to 100-4,000 m (330-13,120 ft) in height.

Mountains are formed through tectonic forces, erosion, or volcanism, which act on time scales of up to tens of millions of years.

Ash from a Yellowstone hotspot eruption 10-12 million years ago created these fossilized bone beds.

A fissure vent, also known as a volcanic fissure, eruption fissure or simply a fissure, is a linear volcanic vent through which lava erupts, usually without any explosive activity.

A somma volcano, also known as a sommian, is a volcanic caldera that has been partially filled by a new central cone.

In geology, a resurgent dome is a dome formed by swelling or rising of a caldera floor due to movement in the magma chamber beneath it.

A complex volcano, also called a compound volcano or a volcanic complex, is a mixed landform consisting of related volcanic centers and their associated lava flows and pyroclastic rock.

In volcanology, a pyroclastic shield or ignimbrite shield is an uncommon type of shield volcano.

A rootless cone, also formerly called a pseudocrater, is a volcanic landform which resembles a true volcanic crater, but differs in that it is not an actual vent from which lava has erupted.

A lava spine (or lava spire) is a vertical growth of solid lava that is forced from a volcanic vent.

Geologically, a volcanic island is an island of volcanic origin.

The Lesser Antilles are mostly young volcanic islands created by the Lesser Antilles subduction zone.

Altogether, there are about 90 islets and reefs, volcanic rocks formed in the Cenozoic era, more specifically 4.6 to 2.5 million years ago.

The archipelago represents the remnants of a long-extinct ring volcano rising from a seabed plateau approximately 40 metres (130 ft) below sea level.

The Chagos group is a combination of different coralline rock structures topping a submarine ridge running southwards across the centre of the Indian Ocean, formed by volcanoes above the Réunion hotspot.

The Poor Knights Islands are the eroded remnants of a 4-million-year-old rhyolitic volcano that is estimated to have been 1,000 metres (3,300 ft) tall and 25 kilometres (16 mi) in diameter.

All the islands are of volcanic origin.

Basilan, Jolo, Tawi-Tawi and other islands in the group are extinct volcanic cones rising from the southernmost ridge.

Marotiri, with an area of 0,043 km2, is a group of four uninhabited volcanic rocks protruding from the sea (and several submerged rocks), forming the southeastern end of the Austral Islands of French Polynesia.

The space between the two islets is the old volcanic crater formed of tuff rock and is approximately 20 metres (66 ft) deep.

Diamond Rock (French: Rocher du Diamant) is a 175-meter-high (574-foot) basalt island located south of "Grande Anse du Diamant" before arriving from the south at Fort-de-France, the main port of the Caribbean island of Martinique.

The fossil beds were laid down in a lake roughly 15-million-years ago, when a drainage basin was dammed by the flood basalts of the Columbia River Plateau.

Fajã (Portuguese pronunciation: [fɐˈʒɐ̃], of unknown etymology) is a Portuguese term of obscure origin used to describe supratidal talus at the foot of coastal cliffs, caused by landslides or lava flows.

A laccolith forms when magma (molten rock) rising through the Earth's crust begins to spread out horizontally, prying apart the host rock strata.

Formation occurs at depths between 150 and 450 kilometres (93 and 280 mi), potentially from anomalously enriched exotic mantle compositions, and they are erupted rapidly and violently, often with considerable carbon dioxide and other volatile components.

Novarupta was formed in 1912, during the largest volcanic eruption of the 20th century, in which it released 30 times the volume of magma of the 1980 eruption of Mount St. Helens.

Occurring during the supergreenhouse climate of the Early Toarcian Thermal Maximum (ETTM), the Early Toarcian extinction was associated with large igneous province volcanism, considerable CO2 emissions which elevated global temperatures, acidified the oceans, increased continental weathering and nutrients fluxes

The petrified forest was formed in connection with the eruption of the Zeisigwald volcano in the lower Permian and dates back about 291 million years.

The volcano has erupted relatively frequently since the Last Glacial Period, most recently in 2010, when, although relatively small for a volcanic eruption, it caused enormous disruption to air travel across northern and western Europe for a week.

According to Charles Darwin's subsidence model, the formation of an atoll is explained by the sinking of a volcanic island around which a coral fringing reef has formed.

The islands are volcanic in origin; Saya de Malha (35 mya) was the first of the Mascarene islands to rise out of the Indian Ocean due to the Réunion hotspot, followed by Nazareth Bank (approximately 2 mya later), Soudan Bank and Cargados Carajos.

The larger islands are volcanic in origin, mountainous, and covered in tropical moist forest.

Finally, volcanic actions created rounded, symmetrical domes like breasts, which were given the name of Demoiselles (or "young ladies"), though this is disputed.

The coral reefs are situated on the top of a large shield volcano, produced by eruptions of the Tasmantid Seamount Chain.