| Tanganasoga | |
|---|---|
 A large brown ring within the largest green area marks the location of the cinder cone. | |
| Highest point | |
| Elevation | 1,384 m (4,541 ft) |
| Coordinates | 27°45′N18°00′W / 27.750°N 18.000°W |
| Geography | |
| Location | El Hierro, Canary Islands |
| Parent range | Canary Islands |
| Geology | |
| Mountain type | Cinder cone atop shield volcano |
Tanganasoga is the main volcano of El Hierro's El Golfo area in the Canary Islands, consisting of a cinder cone. The volcano is part of a much larger shield volcano system. [1]
El Hierro is a 278.5 km2 island, formed approx 1.2 million year ago [2] after three successive eruptions, the island emerged from the ocean as a triangle of basaltic dykes topped with a volcanic cone more than 2,000 metres high. [3] With continued activity resulting in the island expanding to have the largest number of volcanoes in the Canaries (over 500 cones, another 300 covered by more recent deposits), together with approximately 70 caves and volcanic galleries, including the Cueva de Don Justo whose collection of channels is over 6 km in length. [3] Landslides have reduced the size and height of the island. [3] Tanganasoga is now the main volcano on the island.
There is evidence of at least three major gravitational landslides that have affected El Hierro in the last few hundred thousand years. [4] The most recent of these was the 'El Golfo' landslide that occurred about 15 thousand years ago, involving collapse of the northern flank of the island. The landslide formed the El Golfo valley and created a debris avalanche with a volume of 150–180 km3. Turbidite deposits related to this landslide have been recognized in drill cores from the Agadir Basin to the north of the Canary Islands. [5] Detailed analysis of these deposits suggests that the slope failure did not occur as a single event but a series of smaller failures over a period of hours or days. Local tsunami are likely to have been triggered by these landslides but no evidence has been found to confirm this. [4] Tanganasoga formed near the top of the El Golfo landslide headwall, on the upper part of the north-facing scarp slope.
Perhaps as a mark of the island's relative isolation, only one eruption has ever been recorded on the island, from the Volcan de Lomo Negro vent of Tanganasoga in 1793. The eruption lasted a month.
It is considered that the 2011-2012 El Hierro eruption at La Restinga in the southernmost part of the island is a vent of Tanganasoga. Swift deformation of Tanganasoga was recorded during the October 2011-March 2012 eruptive phase of this volcanic activity, and in June 2012 a new phase was heralded by earthquakes and rapid deformation upwards and outwards of Tanganasoga, indicating the deep-seated movement of magma below.
La Palma, also known as La isla bonita and historically San Miguel de La Palma, is the most northwesterly island of the Canary Islands, Spain. La Palma has an area of 708 square kilometres (273 sq mi) making it the fifth largest of the eight main Canary Islands. The total population at the end of 2020 was 85,840, of which 15,716 lived in the capital, Santa Cruz de La Palma and about 20,467 in Los Llanos de Aridane. Its highest mountain is the Roque de los Muchachos, at 2,426 metres (7,959 ft), being second among the peaks of the Canaries after the Teide massif on Tenerife.
El Hierro, nicknamed Isla del Meridiano, is the second-smallest and farthest-south and -west of the Canary Islands, in the Atlantic Ocean off the coast of Africa, with a population of 10,968 (2019). Its capital is Valverde. At 268.51 square kilometres (103.67 sq mi), it is the second-smallest of the eight main islands of the Canaries.
The Lassen volcanic area presents a geological record of sedimentation and volcanic activity in and around Lassen Volcanic National Park in Northern California, U.S. The park is located in the southernmost part of the Cascade Mountain Range in the Pacific Northwest region of the United States. Pacific Oceanic tectonic plates have plunged below the North American Plate in this part of North America for hundreds of millions of years. Heat and molten rock from these subducting plates has fed scores of volcanoes in California, Oregon, Washington and British Columbia over at least the past 30 million years, including these in the Lassen volcanic areas.
Tephra is fragmental material produced by a volcanic eruption regardless of composition, fragment size, or emplacement mechanism.
Mount Mazama is a complex volcano in the western U.S. state of Oregon, in a segment of the Cascade Volcanic Arc and Cascade Range. Most of the mountain collapsed following a major eruption approximately 7,700 years ago. The volcano is in Klamath County, in the southern Cascades, 60 miles (97 km) north of the Oregon–California border. Its collapse, due to the eruption of magma emptying the underlying magma chamber, formed a caldera that holds Crater Lake. The mountain is in Crater Lake National Park. Mount Mazama originally had an elevation of 12,000 feet (3,700 m), but following its climactic eruption this was reduced to 8,157 feet (2,486 m). Crater Lake is 1,943 feet (592 m) deep, the deepest freshwater body in the U.S. and the second deepest in North America after Great Slave Lake in Canada.
Teide, or Mount Teide, is a volcano on Tenerife in the Canary Islands, Spain. Its summit is the highest point in Spain and the highest point above sea level in the islands of the Atlantic. If measured from the ocean floor, its height of 7,500 m (24,600 ft) makes Teide the third-highest volcano in the world, and is described by UNESCO and NASA as Earth's third-tallest volcanic structure. Teide's elevation above sea level makes Tenerife the tenth highest island in the world.
The Cumbre Vieja is an active volcanic ridge on the island of La Palma in the Canary Islands, Spain. The spine of Cumbre Vieja trends in an approximate north–south direction, comprising the southern half of La Palma, with both summit ridge and flanks pockmarked by dozens of craters and cones. The latest eruption began on 19 September 2021 in a forested area of Las Manchas locality known as Cabeza de Vaca. Voluminous lava flows quickly reached populated areas downslope, fanning out across settlements and banana plantations, destroying thousands of buildings and ultimately pouring over steep cliffs into the ocean to enlarge the island at several locations. The volcano went quiet on 13 December 2021, and on 25 December 2021, the local government declared the eruption to be over.
The Garibaldi Volcanic Belt is a northwest–southeast trending volcanic chain in the Pacific Ranges of the Coast Mountains that extends from Watts Point in the south to the Ha-Iltzuk Icefield in the north. This chain of volcanoes is located in southwestern British Columbia, Canada. It forms the northernmost segment of the Cascade Volcanic Arc, which includes Mount St. Helens and Mount Baker. Most volcanoes of the Garibaldi chain are dormant stratovolcanoes and subglacial volcanoes that have been eroded by glacial ice. Less common volcanic landforms include cinder cones, volcanic plugs, lava domes and calderas. These diverse formations were created by different styles of volcanic activity, including Peléan and Plinian eruptions.
The Mount Meager massif is a group of volcanic peaks in the Pacific Ranges of the Coast Mountains in southwestern British Columbia, Canada. Part of the Cascade Volcanic Arc of western North America, it is located 150 km (93 mi) north of Vancouver at the northern end of the Pemberton Valley and reaches a maximum elevation of 2,680 m (8,790 ft). The massif is capped by several eroded volcanic edifices, including lava domes, volcanic plugs and overlapping piles of lava flows; these form at least six major summits including Mount Meager which is the second highest of the massif.
Teneguía is a monogenetic cinder cone – a volcanic vent which has been active once and has had further seismic activity. It is situated on the island of La Palma, one of the Canary Islands, and is located at the southern end of the sub-aerial section of the Cumbre Vieja volcano, of which Teneguía is just one of several vents.
A rift zone is a feature of some volcanoes, especially shield volcanoes, in which a set of linear cracks develops in a volcanic edifice, typically forming into two or three well-defined regions along the flanks of the vent. Believed to be primarily caused by internal and gravitational stresses generated by magma emplacement within and across various regions of the volcano, rift zones allow the intrusion of magmatic dykes into the slopes of the volcano itself. The addition of these magmatic materials usually contributes to the further rifting of the slope, in addition to generating fissure eruptions from those dykes that reach the surface. It is the grouping of these fissures, and the dykes that feed them, that serves to delineate where and whether a rift zone is to be defined. The accumulated lava of repeated eruptions from rift zones along with the endogenous growth created by magma intrusions causes these volcanoes to have an elongated shape. Perhaps the best example of this is Mauna Loa, which in Hawaiian means "long mountain", and which features two very well defined rift zones extending tens of kilometers outward from the central vent.
A cinder cone is a steep conical hill of loose pyroclastic fragments, such as volcanic clinkers, volcanic ash, or scoria that has been built around a volcanic vent. The pyroclastic fragments are formed by explosive eruptions or lava fountains from a single, typically cylindrical, vent. As the gas-charged lava is blown violently into the air, it breaks into small fragments that solidify and fall as either cinders, clinkers, or scoria around the vent to form a cone that often is symmetrical; with slopes between 30 and 40°; and a nearly circular ground plan. Most cinder cones have a bowl-shaped crater at the summit.
San Pedro is a Holocene composite volcano in northern Chile and one of the tallest active volcanoes in the world. Part of the Chilean Andes' volcanic segment, it is part of the Central Volcanic Zone of the Andes, one of the four tracts of the Andean Volcanic Belt. This region of volcanism includes the world's two highest volcanoes Ojos del Salado and Llullaillaco. San Pedro, like other Andean volcanoes, was formed by the subduction of the Nazca Plate beneath the South America Plate. It has a neighbouring volcano, San Pablo, and is itself formed by two separate edifices usually known as the Old Cone and the Young Cone. These edifices are formed by rocks ranging from basaltic andesite over andesite to dacite and are emplaced on a basement formed by Miocene volcanic rocks.
A Surtseyan eruption is an explosive style of volcanic eruption that takes place in shallow seas or lakes when rapidly rising and fragmenting hot magma interacts explosively with water and with water-steam-tephra slurries. The eruption style is named after an eruption off the southern coast of Iceland in 1963 that caused the emergence of a new volcanic island, Surtsey.
The volcanic history of the Northern Cordilleran Volcanic Province presents a record of volcanic activity in northwestern British Columbia, central Yukon and the U.S. state of easternmost Alaska. The volcanic activity lies in the northern part of the Western Cordillera of the Pacific Northwest region of North America. Extensional cracking of the North American Plate in this part of North America has existed for millions of years. Continuation of this continental rifting has fed scores of volcanoes throughout the Northern Cordilleran Volcanic Province over at least the past 20 million years and occasionally continued into geologically recent times.
The Canadian Cascade Arc, also called the Canadian Cascades, is the Canadian segment of the North American Cascade Volcanic Arc. Located entirely within the Canadian province of British Columbia, it extends from the Cascade Mountains in the south to the Coast Mountains in the north. Specifically, the southern end of the Canadian Cascades begin at the Canada–United States border. However, the specific boundaries of the northern end are not precisely known and the geology in this part of the volcanic arc is poorly understood. It is widely accepted by geologists that the Canadian Cascade Arc extends through the Pacific Ranges of the Coast Mountains. However, others have expressed concern that the volcanic arc possibly extends further north into the Kitimat Ranges, another subdivision of the Coast Mountains, and even as far north as Haida Gwaii.
The Mount Cayley volcanic field (MCVF) is a remote volcanic zone on the South Coast of British Columbia, Canada, stretching 31 km (19 mi) from the Pemberton Icefield to the Squamish River. It forms a segment of the Garibaldi Volcanic Belt, the Canadian portion of the Cascade Volcanic Arc, which extends from Northern California to southwestern British Columbia. Most of the MCVF volcanoes were formed during periods of volcanism under sheets of glacial ice throughout the last glacial period. These subglacial eruptions formed steep, flat-topped volcanoes and subglacial lava domes, most of which have been entirely exposed by deglaciation. However, at least two volcanoes predate the last glacial period and both are highly eroded. The field gets its name from Mount Cayley, a volcanic peak located at the southern end of the Powder Mountain Icefield. This icefield covers much of the central portion of the volcanic field and is one of the several glacial fields in the Pacific Ranges of the Coast Mountains.
The 2011–2012 El Hierro eruption occurred just off the island of El Hierro, the smallest and farthest south and west of the Canary Islands, in the Atlantic Ocean off the coast of Africa. The island is also the youngest in the volcanic chain. The October 2011 – March 2012 eruption was underwater, with a fissure of vents located approximately 2 kilometres to the south of the fishing village of La Restinga on the southern coast of the island. Increased seismicity in June 2012 to the north-west of the vent did not result in another phase of eruptive activity. Until the 2021 La Palma eruption, which started on 19 September 2021, this was the last volcanic eruption in Spain.
The geology of the Canary Islands is dominated by volcanic rock. The Canary Islands and some seamounts to the north-east form the Canary Volcanic Province whose volcanic history started about 70 million years ago. The Canary Islands region is still volcanically active. The most recent volcanic eruption on land occurred in 2021 and the most recent underwater eruption was in 2011-12.
The island of La Palma in the Canary Islands is at risk of undergoing a large landslide, which could cause a tsunami in the Atlantic Ocean. Volcanic islands and volcanoes on land frequently undergo large landslides/collapses, which have been documented in Hawaii for example. A recent example is Anak Krakatau, which collapsed to cause the 2018 Sunda Strait tsunami.