Nameless volcano. The devastating effects of the eruption

Nameless- an active volcano in Kamchatka, near Klyuchevskaya volcano, about 40 km from the village of Klyuchi, Ust-Kamchatsky district.

State of the art[ | ]

The absolute height is 2882 m (up to 3075 m), it includes the remains of the old volcano destroyed by the 1956 eruption (in the southeastern part of the massif), a young active stratovolcano and a crater on the site of an old volcano with a diameter of 1.3x2.8 km ... On the slopes there are numerous lava flows, at the foot there are 16 extrusive domes.

Eruptions [ | ]

Volcano Bezymyanny before the catastrophic eruption of 1955-56

The famous catastrophic volcanic eruption on March 30, 1956 was identified by G. S. Gorshkov and G. E. Bogoyavlenskaya as an independent type - "directed explosion" or "Bezymyanny type", which is recognized by world volcanology ("directed blast", "lateral blast", "Type Bezymianny").

Eruption 1955-1956[ | ]

Eruption 1955-1956 was the first in this area since 1697 and occurred, according to tephrochronological studies, after a 1000-year dormant period. Before the eruption, the volcano had the shape of a regular cone 3085 m high (a stratovolcano of predominantly andesite composition, complicated by summit and side extrusive domes). The eruption began on October 22, 1955 after a 23-day swarm of earthquakes. Until March 30, 1956, the eruption was of a moderate, Vulcan character ( pre-culmination stage). During this period, a crater with a diameter of 800 m was formed at the top of the volcano, from which there were frequent emissions of ash to a height of 2-7 km. At the end of November, the squeezing of a dome of viscous lava began in the crater. Simultaneously with the growth of the intracrater dome, a strong swelling of the southeastern slope of the volcano began. The magnitude of the deformation, estimated from the photographs, reached 100 m. The deformation of the slope was associated with the fact that part of the magmatic melt penetrated in the form of a cryptodome (near-surface intrusion) into the edifice of the volcano.

Catastrophic eruption on March 30, 1956 ( culmination stage) was provoked by the collapse of the eastern slope of a volcanic structure with a volume of 0.5 cubic meters. km. The collapse has transformed into a cold (< 100 °С) обломочную лавину , скорость которой превышала 60 м/с. Обломочная лавина образовала три ветви, вложенные в речные долины . Максимальный путь (22 км) прошла центральная ветвь. В процессе распространения обломочная лавина сдирала и толкала перед собой вал материала подножья вулкана (снег, почву, аллювий , растительность), который образовал протяжённые грязевые потоки. Сразу за обрушением последовал катастрофический направленный взрыв, вызванный тем, что обвал резко уменьшил литостатическое давление на магму , внедрившуюся в постройку на докульминационной стадии извержения. Материал, выброшенный взрывом (0,2 куб.км.), распространился вдоль восточного подножия вулкана в виде пирокластической волны (турбулентный поток горячей смеси газа и пирокластики). Скорость потока превышала 60 м/с, температура составляла около 300 °C. После направленного взрыва произошло извержение пирокластических потоков протяжённостью более 20 км. Высота эруптивного облака извержения достигла высоты около 35 км. В результате извержения образовался подковообразный кратер диаметром ~1,3 км, открытый на восток. У восточного подножья вулкана на площади ~500 км² деревья и кустарники были сломаны и повалены в направлении от вулкана. В зоне разрушений возник покров специфических пирокластических отложений (отложения направленного взрыва). После пароксизма (post-culmination stage) in a horseshoe-shaped crater, a dome of viscous lava began to squeeze out, the formation of which continues to the present time.

Formation of the "New" dome[ | ]

The formation of the Novyi dome began immediately after the culmination stage on March 30, 1956. In the early years, the dome was continuously squeezed out of rigid obelisks. Subsequently, the growth of the dome became discontinuous and, along with rigid blocks, from 1977, viscous lava flows began to be squeezed out. The viscosity of the lava continues to decrease gradually and the length of the lava flows gradually increases (the decrease in viscosity is due to a gradual decrease in the content of silicic acid). Currently, lava flows cover the entire surface of the dome, which almost filled the crater in 1956. The formation of the dome throughout its history has been accompanied by weak and moderate explosive eruptions with the deposition of small block-ash pyroclastic flows and associated pyroclastic ash cloud waves. The frequency of eruptions reaches 1-2 per year. Among the explosive eruptions accompanying the growth of the dome, relatively strong eruptions in 1977, 1979, 1985, and 1993 can be distinguished. The longest pyroclastic flows associated with the growth of the Novy dome covered a distance of 12.5 km (1985). Until 1984, pyroclastic flows did not have a noticeable eroding effect. In the course of subsequent eruptions, pyroclastic flows began to cut troughs on the slope of the dome. Simultaneously with the intensification of the eroding effect of pyroclastic flows during eruptions, large collapses of the old parts of the dome began to occur. The largest collapse of the dome occurred during the 1985 eruption along the Bezymyanny volcano in Kamchatka.

• Malyshev A.I. Volcano life. - Yekaterinburg: Publishing house of the Ural Branch of the Russian Academy of Sciences, 2000 .-- 262 p.
• Alidibirov M.A., Bogoyavlenskaya G.E., Kirsanov I.T. et al. Eruption of the Bezymyanny volcano in 1985 // Volcanology and seismology. - 1988. - S. 3-17.
• Deposits and sequence of events of the Bezymyanny volcano eruption on March 30, 1956 (Kamchatka): debris avalanche deposits // Volcanology and seismology. - 1998. - No. 1. - S. 25-40.
• Belousov A.B., Belousova M.G. Deposits and sequence of events of the eruption of Bezymyanny volcano on March 30, 1956 (Kamchatka): deposits of directional explosion // Volcanology and seismology. - 2000. - No. 2. - S. 3-17.
• Bogoyavlenskaya G.E., Kirsanov I.T. Twenty-five years of volcanic activity of the Bezymyanny volcano // Volcanology and seismology. - 1981. - No. 2. - S. 3-13.
• Gorshkov G.S., Bogoyavlenskaya G.E. Bezymyannaya hill in 1956-1958 // Bulletin of Volcanology. - M.: Nauka, 1961. - No. 31. - S. 17-22.
• Dubik Yu.M., Menyailov I.A. New stage eruptive activity of Bezymyanny volcano // Volcanoes and eruptions. - M.: Nauka, 1969 .-- S. 38-77.
• Florensky P.V. Unique frames // Nature. - 2007. - No. 1. - S. 38-39.
• Belousov A., Voight B., Belousova M. Directed blasts and blast-currents: a comparison of the Bezymianny 1956, Mount St Helens 1980, and Soufriere Hills, Montserrat 1997 eruptions and deposits // Bulletin of Volcanology. - 2007. - No. 69. - S. 801-840.
• ... Scale: 1: 100,000. State of the area in 1979. Edition 1986

It is a natural monument, which is located on the territory included in 2001 in the list of the World Natural and Cultural Heritage of UNESCO in the nomination "Volcanoes of Kamchatka".

Volcano Bezymyanny is located in the central part of the Klyuchevskoy group of volcanoes, southwest of it, on a slope. The height of the volcano is 2882 m above sea level. It is a massif elongated in the latitudinal direction with a destroyed summit, which is occupied by a huge crater 1.3x2.8 km in size. There are 16 small domes of various sizes and ages at the southern and southwestern foot of the massif. For its location, blocking the path between the upper reaches of the Studennaya and Bolshaya Khapitsa rivers, this chain of volcanic domes was named By the dam(with stress on the last syllable). On the northwestern slope of the "Plotina" there are two peculiar outcrops, similar in appearance to stacked firewood - woodpiles.

The history of the volcano began 10-11 thousand years ago, when the Pra-Bezymyanny volcano began to form on the spurs. Most of this volcano was destroyed by the catastrophic eruption of 1956. The Bezymyanny stratovolcano itself arose about 5 thousand years ago. After the catastrophe of 1956, the Novy dome began to grow in the newly formed crater, the formation of which continues to the present day.

Since opening Kamchatka Russian explorers (1697) did not notice any signs of Bezymyanny volcano activity. And suddenly on October 22, 1955, at about 6 o'clock in the morning, an explosion followed and a gas-ash cloud rose over the volcano to a height of several kilometers, enveloping everything around in darkness. The eruption continued until early December. The force of the eruption was not the same, and it passed unevenly. The strongest impulses were noted by the rise of a gas-ash cloud to a height of 6-7 km. At the beginning of the next year, 1956, the quiet evolution of gases continued, to which ash and lava emissions were sometimes mixed.

March 30, 1956 was the culmination of the volcanic eruption. There was a tremendous explosion directed to the east at an angle of 40-45 ° to the horizon. The explosion destroyed the top of the volcano, changed its shape and the relief of the surrounding area. The top of the volcano dropped 200-300 m; a huge crater with a size of 1.3x2.8 km was formed. A directed explosion raised a huge gas-heat cloud to an altitude of 34-38 km. It expanded to 50 km and swept at a speed of 100 km / h. By the force of the explosion, large trees were broken, felled and in places burned at a distance of up to 25 km. The incandescent material was deposited over an area of ​​about 500 km 2, destroying all vegetation, including 400 km 2 of forest.

Powerful streams of incandescent volcanic material poured through the gap formed in the crater ( pyroclastic streams), which filled the valley of the Sukhaya Khapitsa River with a length of 18 km. They caused a rapid melting of snow, which contributed to the formation of violent mud flows, which, having reached the Bolshaya Khapitsa stream, turned along the valley to the north, demolishing everything in their path and passing about 90 km, merged into. The mud stream was an incredible mixture of debris and vegetation; when it flows into it, it has reached almost 6 kilometers in width.

One of the most violent eruptions on the dome was in 1985. A directed explosion destroyed the houses of volcanologists located on the northern ridge, 3.5 km from the center of the eruption. During the eruption, a rather large collapse of the eastern slope of the dome occurred.

Starting from the edifice of the volcano and at a distance of 10-12 km from it, the surface of the explosive deposits is visible. This is an extraordinary chaos of volcanic material (mutilated boulders, bombs, lapilli, sand and ash) thrown out by the explosion.

Used sources:

Ilyushkina L. M., Zavadskaya A. V. Natural monuments of Kamchatka. Petropavlovsk-Kamchatsky: Kamchatpress Publishing House, 2008

Rudich K. N. Stone torches of Kamchatka. Publishing house "Science", Novosibirsk, 1974

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Bezymyannaya Sopka Volcano (Bezymyannaya Volcano)

Located in the central part Klyuchevskoy group of volcanoes, southwest of Klyuchevskoy volcano, its current height is 2882 m. Nameless volcano was considered extinct. The absence of any signs of activity in historical time caused some disdain for him at that time. In 1955, seismographs of the Klyuchevskaya station began to register numerous tremors in the direction of Bezymyanny. But the distrust in him was so strong that the tremors were considered harbingers of the appearance of some kind of side crater of the Klyuchevskoy volcano.

On October 22, 1955, the eruption of Bezymyanny began with powerful ash eruptions that rose to a height of 5 km, but then the volcano began to subside, and it seemed that its awakening would end there. But on March 30 of the following year, 1956, a grandiose explosion shook the surroundings, and a huge ash cloud shot up to a height of 35 km. The top of the volcano was destroyed, a crater with a diameter of 1.5 km was formed in its place, and the height of the volcano decreased by 250 m.

Explosions at a distance of up to 25 km felled or burned trees, covered with bushes. Hot ash, sand, debris covered an area of ​​about 500 km2 with a thick layer, destroying all vegetation. The masses of snow accumulated over the winter were quickly melted, and mud streams rushed into the valley of the Bolshaya Khapitsa River, carrying trees and debris of all sizes there. Powerful flow swept along its valley, forming an impenetrable blockage of trees, stones and mud before its confluence with the Kamchatka River. The muddy water of this stream, poisoned with sulfurous impurities, made the water of Kamchatka unfit for drinking for many days and caused a massive death of fish. After the formation of the crater, a dome of viscous incandescent lava began to squeeze out from its bottom - a new cone.

The 1956 eruption is considered one of the largest on a scale of the entire Earth in historical time. After him, two weak eruptions took place on Bezymyanny in 1961, 1966 and a stronger one in 1977. Activation was observed in 1984, but in 1985 the volcano presented a new surprise.

At the end of June, tremors began to be recorded. A group of volcanologists was urgently sent. And on June 29, the volcano exploded. Again there was a directed explosion to the east, but of enormous power, in strength - the second after the explosion of 1956. Nobody imagined this. The nature of the volcano was considered sufficiently studied, they got used to the tremors, and the group almost died.

A scorching cloud swept for 12 km, destroying the young vegetation that had just begun an attack on the desert. The houses built by volcanologists near the volcano were also destroyed, fortunately uninhabited. The new dome that grew after the eruption of 1956 survived, but the size of the crater increased.

Currently, due to frequent rock avalanches and high gas concentration, visiting the top of the dome without special equipment is not recommended. In addition, high volcanic activity remains, the volcano periodically produces ash emissions to a height of up to several kilometers.

Nature and its exploration by man

The Kamchatka Peninsula belongs to the northern part of the Pacific seismic belt, where earthquakes are frequent and fiery mountains are found in abundance. The entire northern part of this belt is represented mainly by islands, it is the local island arcs that are, in the words of geologists, “fire-breathing”. Thus, Kamchatka is an amazing exception, since there are many volcanoes on the peninsula, including active or dormant ones. Volcano Bezymyanny (3085 m) lies in the Eastern ridge and is located in the so-called Klyuchevskoy group, which includes many other Kamchatka volcanoes. The main fiery mountain of the group is Klyuchevskaya Sopka, but Bezymyanny has won, perhaps, the greatest fame.

The eruption in 1955-1956 was the greatest volcanic catastrophe of the past century. Fortunately, the volcano is located far from settlements, so the cataclysm was not accompanied by destruction and loss of life. Due to the remoteness from cities and towns, this volcano did not receive any name for a long time. That is why he entered the work on volcanology under the name Nameless. The volcano, considered extinct, woke up after many years of sleep in the early morning of October 22, 1955 and began throwing out clouds of hot ash and clouds of grains of sand. A column of dust particles shot up into the air to a height of 8000 m. A thick ash fall began, forcing the residents of the neighboring village of Klyuchi to turn on the lighting during the day. Over the next month, Bezymyanny only threw out ashes, but the externally undetectable subsoil activity was growing.

Hot sand and ash, falling in tons from the sky, caused intense melting of snow near the Bezymyanny hill. As a result, powerful mud flows arose, which rushed down to the river valleys.

The crater of the volcano slowly but steadily grew and eventually increased 3.2 times, reaching a diameter of 800 m. Over time, activity gradually subsided, and in early December, the volcano's mouth was completely blocked by solidified lava. Therefore, the pressure of the accumulating gases began to grow inside the channel. Under their influence, the dome of lava bedding rose by 100 m and shifted in a southeast direction. An explosion of gases occurred on March 30, 1956.

Origin and age

All Kamchatka volcanoes are very young geologically, most of them are no more than 60 thousand years old. The history of volcanism on the peninsula goes back deep into the past. Over 70 million years ago, Kamchatka was a chain of volcanic islands like the Kuril ridge, and only more than 60 million years later the islands united into a solid massif that joined the continent.

Destruction of the Bezymyanny cone as a result of the eruption in 1956. The outline shows the original size of the volcanic hill, the volumetric drawing depicts the current outlines of the stratovolcano.

About 3 million years ago, mountain building began on the peninsula, while the first volcanic cones of a new era began to form along the growing mountain ranges. After 1 million years, the Kamchatka Peninsula was dotted with ancient shield volcanoes. Subsequently, 50-60 thousand years ago, hills of modern stratovolcanoes (layered), including Bezymyanny volcano, grew on the surface of these volcanoes.

Ridges with an average height of 2000-2500 m stretch around the cones of the Klyuchevskoy group. The slopes of the ridges are covered with a coniferous forest. But during the eruptions by the outpouring of lava, the forests on the volcanic hills are completely tumbled down or burned out.

Bezymyanny is an active volcano in Kamchatka, near Klyuchevskaya Sopka, about 80 km from the village of Klyuchi, Ust-Kamchatsky District.
Height 2882 m (up to 1956 - 3075 m), it includes the remains of an old volcano destroyed by the eruption of 1956 (in the southeastern part of the massif), a young active stratovolcano and a crater on the site of an old volcano with a diameter of 1.3x2.8 km. On the slopes there are numerous lava flows, at the foot there are 16 extrusive domes.
The famous catastrophic volcanic eruption on March 30, 1956 was highlighted by G.S. Gorshkov and G.E. Epiphany into an independent type - "directed explosion" or "type Nameless", which is recognized by world volcanology ("directed blast", "lateral blast", "type Bezymianny").

Eruption 1955-1956 was the first for historical period(in this area since 1697) and happened, according to tephrochronological studies, after a 1000-year dormant period. Before the eruption, the structure of the volcano had the shape of a regular cone 3085 m high (a stratovolcano of predominantly andesitic composition, complicated by summit and side extrusive domes). The eruption began on October 22, 1955 after a 23-day swarm of earthquakes. Until March 30, 1956, the eruption was of a moderate, Vulcan character (pre-culmination stage). During this period, a crater with a diameter of 800 m was formed at the top of the volcano, from which there were frequent emissions of ash to a height of 2-7 km. At the end of November, the squeezing of a dome of viscous lava began in the crater. Simultaneously with the growth of the intracrater dome, a strong swelling of the southeastern slope of the volcano began. The magnitude of the deformation, estimated from the photographs, reached 100 m. The deformation of the slope was associated with the fact that part of the magmatic melt penetrated in the form of cryptoculole (near-surface intrusion) into the edifice of the volcano.

The catastrophic eruption on March 30, 1956 (culmination stage) was triggered by the collapse of the eastern slope of a volcanic edifice with a volume of 0.5 cubic meters. km. The collapse has transformed into a cold (< 100°С) обломочную лавину, скорость которой превышала 60 м/с. Обломочная лавина образовала три ветви, вложенные в речные долины. Максимальный путь (22 км) прошла центральная ветвь. В процессе распространения обломочная лавина сдирала и толкала перед собой вал материала подножья вулкана (снег, почву, аллювий, растительность), который образовал протяженные грязевые потоки. Сразу за обрушением последовал кастрофический направленный взрыв, вызванный тем, что обвал резко уменьшил литостатическое давление на магму, внедрившуюся в постройку на докульминационной стадии извержения. Материал, выброшенный взрывом (0,2 куб.км.), распространился вдоль восточного подножия вулкана в виде пирокластической волны (турбулентный поток горячей смеси газа и пирокластики). Скорость потока превышала 60 м/с, температура составляла около 300 градусов С. После направленного взрыва произошло извержение пирокластических потоков протяжённостью более 20 км. Высота эруптивного облака извержения достигла высоты около 35 км. В результате извержения образовался подковообразный кратер диаметром ~1,3 км, открытый на восток. У восточного подножья вулкана на площади ~500 кв. км деревья и кустарники были сломаны и повалены в направлении от вулкана. В зоне разрушений возник покров специфических пирокластическлх отложений (отложения направленного взрыва). После пароксизма (посткульминационная стадия) в подковообразном кратере начал выжиматься купол вязкой лавы, формирование которого продолжается до настоящего времени.