Vulcan alive or inanimate. Volcano - a miracle of nature. Secrets and secrets of nature

Volcano - the most formidable and dangerous phenomenon of nature. Ancient people associated these phenomena with the gods and their activities. For example, the Aztec Indians were convinced that their gods lived in lava. And in order to appease the gods, they sacrificed young beautiful girls to them.

Volcanic eruption in ancient Greece

During the Middle Ages, people believed that volcanoes are the door to the underworld itself.

Over the past 300 years, according to scientists, at least 250 thousand people have died from volcanic eruptions in various parts of our planet. Very often, areas adjacent to volcanoes were subjected to the complete or partial destruction of houses and agricultural crops. This led to hunger among the population and, as a result, to numerous additional casualties.

Lava can flow from the vent of volcanoes at speeds up to 90 km / h. This speed is comparable to the speed of a car moving on a straight road free from other cars.

Catastrophic Volcanic Eruptions

The worst eruption of the last century occurred in 1902 on the island of Martinique (West India). Mon Pele Volcano destroyed the entire population of the island (30,121 people), except for two - a shoemaker, whose house was on the edge of the island and a prisoner who was in the cell of a local prison with very thick stone walls.

And the eruption of a volcano in Indonesia (Lake Toba), about 75,000 years ago, led to a dramatic climate change throughout the entire planet Earth. This epoch is known as the Ice Age.

Almost 80% of volcanoes are on land, and about 20% are under water.

Volcanoes are dangerous not only with red-hot lava, but also with poisonous gases. In 1986 in Cameroon (West Africa) from Lake Nyos at the bottom of which is located an active volcano, a cloud of water and carbon dioxide rose. It descended into the valley and caused deadly suffocation in 1,700 people and 3,500 domestic animals living in the villages near the volcano.

What is a volcano

A volcano is a geological formation located on the surface of the entire crust, where hot magma came to the surface, while forming liquid hot lava, as well as pyroclastic flows, volcanic gases and stones - the so-called volcanic bombs.

Volcano classification

Scientists classify volcanoes by their form, they are: thyroid, slag cones, dome and stratovolcanoes. In addition, volcanoes differ depending on the degree of their activity: dormant, dormant, extinct and active, as well as according to their location: underwater, terrestrial, subglacial, and some others.

Researchers consider an active volcano to be the one that erupted in the long historical period of that time or in the Holocene, that is, glaciation, dating back to the Quaternary, which lasts for the last 12,000 years to the present. However, the concept of "active" volcano is quite inaccurate, since the volcano itself, which has active fumaroles, some scientists refer to as extinct, and some scientists - to the active. The currently inactive volcanoes are considered to be sleeping volcanoes, where small eruptions are possible, and those volcanoes that are unlikely to be erupted are considered to be extinct volcanoes. Along with this, among the scientists of volcanologists there is still no concrete concept of how to define an active volcano, since the period of activity of a volcano can last from several months to even several million years. It is noteworthy that many volcanoes showed their activity 10,000 years ago, however, in our time they are not considered active.

Areas of volcanic activity. Red color on the map.

Today, the main regions of volcanic activity are the following: Central America, South America, Melanesia, Java, the Japanese Islands, the Kamchatka Peninsula, the Kuril Islands, the northwestern part of the United States, the Hawaiian Islands, Alaska, the Aleutian Islands, the Atlantic Ocean, Iceland.

Volcanic eruptions are sometimes very catastrophic. For example, in January 1951, an eruption of the Lamington Volcano, located in the territory of the state of New Guinea, killed almost 3,000 people.

An interesting fact is that volcanoes are an elevation of often considerable height, for example, the Mauna Loa volcano, reaches approximately 4170 meters. And the volcano Ruapehu located in the territory of the state of New Zealand reaches a height of 2,796 meters.

The science that studies volcanoes is called volcanology or geomorphology.

New approach to the definition of "active volcano"

I.V. Melekestsev, O.A. Braytseva, V.V.Ponomareva

On the basis of the detailed reconstruction of the eruptive activity of Kamchatka volcanoes, a new approach to the definition of the concept of an active volcano has been developed. It is proposed to consider as active those multi-volcanoes, for which at least one eruption over the last 3000–3500 years has been established and dated. The subgroup of active volcanoes, for which there is information about historically documented eruptions or fumarole manifestations, and a subgroup of potentially active volcanoes, for which these data are not available, but eruptions over the last 3,500 years, are identified. By similar criteria, potentially active fields of areal basaltic volcanism, regional zones of slag cones, and concentrated manifestation of high-temperature extrusive volcanism are also distinguished. It is proposed to use the data obtained for the new catalog of active volcanoes of Kamchatka, a long-term forecast of volcanic activity and the danger associated with it.

Active volcanoes - the most important object of volcanological research. However, to date, there is no scientifically based criterion for dividing volcanoes into active and extinct ones, although this is very important both from a theoretical and, especially from a practical point of view, assessment of volcanic danger. To assess the volcanic hazard, it is first necessary to have a clear idea of ​​whether the volcano is active (potentially active) and whether it should be expected to erupt in the future.

About the term "active volcano"

A direct consequence of the lack of a scientifically based formulation of the concept of "active volcano" is, in our opinion, the seeming unexpectedness of eruptions on volcanoes that were silent for a long time or were generally considered extinct. Well-known, for example, the catastrophic eruptions of Vesuvius 79 AD, El Chichon volcanoes in 1982 (Mexico), Pinatubo in 1991 (Philippines), which were preceded by a rest period of more than 600 years, and a strong eruption of Unzen volcano in 1990-1993 (Japan), following the 200-year break in its activity. For Kamchatka, the volcano Nameless, which before the catastrophic eruption of 1955-1956, is indicative. did not erupt for 1000 years and only conditionally related to the current ones. In this connection, the question arises of what maximum periods of rest are possible in the eruptive history of a volcano, after which it is able to resume its activity and be considered as active.

Unfortunately, there is no exact answer to the question posed in the published works, but in modern volcanology there is an empirical idea that an active or active volcano traditionally means a volcano, for which historical eruptions or historically documented eruptions are known, as well as manifestations of fumarole or solfatara activity . In accordance with this, the international "Catalog of active volcanoes of the World including solfatara fields", published in 1951-1965, was compiled.

However, the criterion of historicity, as rightly stated in the work, is hardly fully acceptable, since the concept of "historical eruptions" is very vague. If the term “historically documented eruptions” is used, different regions find themselves in unequal conditions: for the Mediterranean, the “historical chronicle” is 2500-3000 years, for Iceland - 900 years, for Kamchatka, the Kuril and Aleutian Islands, Alaska - 200-300 years , for Africa and Antarctica - less than 200 years. In some cases this is true even in relation to different parts of a single country. Thus, in Japan, on the islands of Honshu and Kyushu, historically documented eruptions have been known since the 7th and 8th centuries, and on much later colonized Hokkaido - only from the 17th century. In addition, the number of active volcanoes generally shows a clear upward trend with increasing duration, quality and direction of research, especially in sparsely populated areas, where some of the eruptions could simply not be fixed.

The criterion of historicity allows us to unreasonably refer to active volcanoes and one-act volcanic forms that have completed their activity, if they have appeared in front of people. For example, the Monte Nuovo slag cone - 1538, Corullo volcanoes - 1759-1774, Paricutin - 1943-1952, the slag cones of the North - 1975, and the South - 1975-1976. breakthroughs of the Great Tolbachinsky fissure eruption, Uarakrek maary - 1977. It is not advisable to include active volcanoes and solfatar fields in the catalogs, since, by definition, solfataras are associated directly with volcanic activity and with hydrothermal deposits.

Thus, the existing definition of an active volcano, on the one hand, is largely formal and does not take into account geological realities, but on the other hand, it is vague and internally contradictory.

All this can be perfectly illustrated by the example of Kamchatka.

In Kamchatka, the first and only, open at the very end of the 17th century, the Klyuchevskaya volcano became an active volcano, from which, according to V. Atlasov, "the smoke is out during the day and sparks and glow are visible at night" (quoted in).

In the 40-50s of the 18th century, thanks to the studies of S.P. Krasheninnikov and GVSteller, the number of active volcanoes increased to 8: Kamchatka fire-breathing mountain - Klyuchevskaya Sopka, fire-breathing Avachinskaya and Tolbachinskaya mountains, smoking Zhupanovskaya and Shevelich mountains, Apalskaya Sopka, which "in past times was a volcano, emitting thick clouds of smoke from its depths", two smoking mountains 13 miles from Lake Xui (Kuril - authors' note) are the modern Kambalny and Koshelevsky volcanoes in southern Kamchatka that were in 1742 in fumaro stage flax activity or weak eruptions. Four of their eruptions were described: Avachinsky volcano - in the summer of 1737 (strong), Klyuchevsky volcano - between 1727 and 1731. and in September 1737 (catastrophic), Plosky Tolbachik and Tolbachinsky Dol - in December 1740

From the description, we can conclude that the Vilyuchinsky volcano was also active - the Vilyuchinsky volcano, which "smoked in former times". But this is most likely an error, since, according to our tefrochronological studies, the last eruption of the Vilyuchinsky volcano happened more than 7 thousand 14 From years ago. Naturally, even the distant ancestors of the aborigines living during the stay of G.Steller in Kamchatka (1740-1744) could not remember this eruption. Probably, the eruptions of the closely located Mutnovsky and Gorely volcanoes were taken for the eruptions of the Vilyuchinsky volcano.

On the "Map of Kamchatka Volcanoes", compiled by N.G. Kellem based on the results of 1908-1910. The Kamchatka Expedition of FP Ryabushinsky, 12 active volcanoes have already been shown, the coordinates and absolute heights of their peaks have been determined. These are the hills: Shiveluch - 3298 m (Main peak) and 2697 m - (Crater peak), Klyuchevskaya - 4850 m, Tolbachik - 3730 m, Shchapinskaya (Kizimen volcano) - 2800 m, Kikhpinych - 1700 m, Birch (Karymsky volcano) - 1320 m, Zhupanova - 2931 m, Koryak - 3462 m, Avacha - 2720 m, Mutnaya - 2322 m, Shtyubelya - 800 m, Kosheleva - 1800 m. The mapping covered only the East volcanic zone of Kamchatka in its modern sense.

In the first for Kamchatka, the catalog of volcanoes PT Novograblen has in 1931 already 19 active volcanoes (Table 1). He, in fact, was the first in Kamchatka to formulate in general terms the definition of the term "active volcano", calling the volcanoes periodically active and being in the stage of solfatars active. A fundamentally similar definition is given in the 1984 Reference Book on Volcanology. There the volcano belongs to the active ones, "the eruptions of which occur at the present time or took place during historical time, as well as the volcano that detects constant fumarole activity." However, in 1957, V.I. Vlodavets and B.I. Piip included in the "Catalog of active volcanoes of Kamchatka" and "some other large multi-active volcanoes, for which there is no information about their historical eruptions, but which have little changed forms and fresh kind of lava flows. " On this basis, the Krasheninnikov and Kikhpinych volcanoes were attributed to them, and even earlier, according to the same characteristics, B.I.Piip proposed to include the Nameyanny volcano in the composition of the active volcanoes. Thus, an attempt was made when assigning volcanoes to active ones to take into account geological data. However, the concepts of "fresh" and "little changed" are also quite subjective. It should be noted that even with very good preservation, one-act forms are not placed in the catalog. There are a total of 28 active volcanoes in the catalog (see Table 1).

I.Guschenko divided volcanoes into 3 categories: A - active volcanoes with precise dating of eruptions in historical time. B - potentially active volcanoes with an approximate dating of the last eruptions of no more than 3,500 years; C - volcanoes that were in the solfatar stage of activity in historical time and solfatarn fields. I. Guschenko does not provide any justification for the cited figure. We can only assume that it was taken as a reference point in 1500 BC. - the time of the oldest eruptions in his catalog: the estimated date of formation of the Astroni crater and the eruption of Mount Etna in Italy. I.Guschenko brought the list of active volcanoes of Kamchatka to 32 (see Table 1).

Later, the proposed classification principle for active volcanoes was used by V.I. Vlodavtsev in his Volcanology Handbook, although in a slightly modernized form: active volcanoes are highlighted in the stage of strong solfatara-fumarole activity (F) and in the stage of weak sufargent activity (WITH). However, among the 30 active volcanoes of Kamchatka, there are no volcanoes in stage F. in the List of the Directory. There are also no Ostry Tolbachik and Bolshaya Udina volcanoes that are present in the work.

The criteria underlying the selection of active volcanoes in the work "Active volcanoes of Kamchatka", published in 1991, are generally incomprehensible. There, for example, along with the active volcanoes from the previous catalogs are placed "known among volcanologists and nature lovers of the Valley of Geysers" and one-act "New Tolbachinsky volcanoes". Despite this addition, the number of volcanoes, also for unclear reasons, has been reduced to 29.

In the last foreign catalog of 1994, the term active volcano, in fact, is completely absent. There simply collected and summarized information on the chronology of volcanism over the past 10 thousand years. One-act volcanic forms dated by different methods are included there. However, this is a kind of way to get away from assessing whether the volcano is really active and whether it can erupt in the future. Many volcanoes that erupted at the beginning of the Holocene (often completing their Late Pleistocene stage of activity) have not shown any activity for many millennia, and are unlikely to show it in the future. It seems to us that among the volcanoes erupted in the Holocene should be identified those that are potentially active, i.e. may give eruptions in the future. This question is fundamental in any research related to the assessment of volcanic hazard.

We believe that the most promising approach is when the volcano should be considered as valid, based on its eruptive history for a long period of time, preferably from the moment of its occurrence or over the last 5-10 thousand years. An excellent method for the reconstruction of eruptive history is tephrochronology with extensive use of radiocarbon dating. The methodology of such studies has been set forth by us in numerous publications. The study by this method of the history of the activity of active volcanoes of Kamchatka in the Holocene allowed us to determine for them the maximum duration of rest periods, after which the volcanic activity resumes again, and thus use this criterion to classify volcanoes as active.

Maximum breaks in the eruptive activity of volcanoes

To date, the history of the eruptive activity of most active volcanoes of Kamchatka: Shiveluch, Bezymyanny, Kizimen, Krasheninnikov, Kikhpinich, Maly Semyachik, Karymsky, Avachinsky, Gorely, Mutnovsky, Ksudach has been studied with varying degrees of detail. Klyuchevskoy, Koryak, Opala, Ilyinsky, Kambalny, Kosheleva, Gamchen, Komarova volcanoes are in the process of studying and processing materials. Reconnaissance studies were conducted on the Zhupanovsky, Bakening, Vilyuchik, Kozelsky volcanoes. The largest explosive eruptions of the last 10,000 years were also highlighted and dated. The layers of the ashes of these eruptions turned out to be excellent marking horizons, which were used for stratigraphic dissection, dating and correlation of other types of volcanic deposits, and for determining the age of various volcanic forms.

The studied volcanoes have different morphology and composition of products. Klyuchevskoy, Bezymyanny, Karymsky volcanoes - usual stratovolcanoes, Krasheninnikova, Kikhpinich, Maly Semyachik - volcanic buildings, including several merged contov-volcanoes cones, Avachinsky - Somma-Vesuvius type volcano, Kizimen - a volcano with a wide development of extruded dressers and wardrobe dressers. explosive eruptions on which were accompanied by caldera. Klyuchevskoy, Krasheninnikov, Kikhpinych, Small Semyachik delivered to the surface mostly basalts and basaltic andesites, and Karimsky Untitled - andesites, Ksudach - andesite and dacite, Avachinskiy - andesites of the first phase of the Holocene and andesite to his young cone.

Analysis of materials on the reconstruction of the activity of the above-listed volcanoes shows that the duration of periods of rest in their activities does not reveal significant differences depending on the morphology of volcanoes or the composition of their magma.

If we do not consider the intervals between eruptions within the eruptive periods themselves, where they are usually measured in years and tens of years, but take the intervals of rest between the activation periods, then they can be considered typical for them to be hundreds of years old. Rest periods of 700–900 years have been established for the Bezymyanny, Krasheninnikova, and Karymsky volcanoes. Even for the Avachinsky volcano with its very intense activity, a period of rest lasting 900 years was revealed (Fig. 1). Rest periods of 1000–2000 years are also frequent, and have occurred at least once in the eruptive history of the volcanoes Kizimen, Maly Semyachik, and Karymsky, as well as on the Ksudach volcano (see Figure 1). It was exactly 1000 years that the rest period continued before the catastrophic eruption of the Bezymyanny volcano of 1955-1956. Periods of rest lasting 2000-3000 years, after which the volcano still retained the ability to resume its activity, took place in the history of Kizimen, Maly Semyachik, Karymsky and twice in the history of Ksudach. They are also noted for Gorely, Opala, Zheltovsky, Ilyinsky and Kambalny volcanoes. Rest periods of little more than 3,000 years have been established for the Zheltovsky and Kambalny volcanoes. On the Kikhpinych volcano, a period of peace of 3,200 years divided the activation periods corresponding to the formation of its two cones, Zapadny and Savich. The longest dormant period (3500 years) is recorded for the Wild Crest volcano (see Fig. 1).

The intervals between the formation of individual volcanic cones that make up the volcanic massifs are quite comparable in duration with the activation periods in the history of volcanoes having a single morphological structure. This is well illustrated by the example of the volcanic massifs Krasheninnikov and Maly Semyachik. The young cone of Maly Semyachik, Kayno-Semyachik, is separated from the previous Mezo-Semyachik cone with a break in activity lasting about 1,700 years, and the formation of the Northern and Southern cones of the Krasheninnikov massif with an interval of rest of 900 years. This indicates that the volcanic massifs of Krasheninnikov and Maly Semyachik are each, in essence, one active volcano. The formation of their individual cones is simply the most economical way to continue the volcanic process: the volcanic cone reaches its height, often giving a series of side breaks at the final stage, providing the magma with access to lower hypsometric levels; At the beginning of a new cycle of activity in the conditions of the extreme height of the building, the volcano's channel moves along the strike and a new cone is formed next to the previous one.

From the foregoing it follows that rest periods lasting 1000–3000 years are common in the eruptive history of Kamchatka volcanoes, after which they resume their activity. The maximum rest period for the studied volcanoes was 3200-3500 years. Based on these data, we propose to consider on Kamchatka those multiact volcanoes that have been unequivocally established and dated at least one eruption over the last 3000–3500 years are valid. Among them are the subgroup of active volcanoes, for which there is information about historically documented eruptions or fumarolic manifestations, and a subgroup of potentially active volcanoes for which these data are not available, but eruptions have been established and dated over the last 3000–3500 years. The latter, after a period of relative rest, are able to resume their activity. Many of them are not only potentially active, but also potentially dangerous volcanoes, which should be given priority attention when developing the territory. It is worth noting that if historical evidence in Kamchatka covered such a time interval as in the Mediterranean, many volcanoes allocated to the second subgroup would be valid according to the accepted criterion of historically documented eruptions. In this regard, it seems to us that the study of its history over the past millennia should be decisive in classifying a volcano as active or extinct.

Proposed list of active volcanoes of Kamchatka

When comparing among themselves the catalogs of active volcanoes of Kamchatka, previous researchers are clearly visible (see Table 1) that their base (60-70%) is made up of a group of 19 volcanoes assigned to the operating PT Novovblenovy in 1931. For various reasons, another 9 volcanoes were placed in a catalog published in 1957 by V.I. Vlodavets and B.Piip. Maly Semyachik and Kambalny volcanoes - due to data on their historical eruptions, Gamchen and Komarov - due to the discovery of fumarole activity in their craters, Bourdy, Central Semyachik and Uzon - due to the constant solfatar and hydrothermal activity that manifests there.

As shown by our research, V.I. Vlodavets and B.I. Pipp were in their time quite correctly attributed to the active volcanoes Bezymyanny and Krasheninnikov. Vulcan Nameless confirmed this famous eruption of 1955-1956. after a thousand year rest period. The Krasheninnikov volcano erupted in the time interval 1100–1300 bp, and its last eruptions were 600 and 400 bp. (see figure 1).

Changes in the later lists of active volcanoes were less significant. I.Guschenko added to the catalog he used 4 volcanoes: Near and Far Flat Fells, Stone, Ostry Tolbachik and Big Udina. V.I. Vlodavets left Near and Far Flat Hills and Stone, but excluded Ostry Tolbachik and Big Udina. Volcanoes Kamen, Ostry Tolbachik and Bolshaya Udina are not present in the work, but the one-act New Tolbachinsky volcanoes were additionally introduced.

Our studies of eruptive activity of volcanoes over the past 10 thousand years and the new approach to the definition of "active volcano" formulated above (see section 2), based on an estimate of the maximum duration of interruptions in volcanoes, allowed, on the one hand, to partially revise existing lists of active volcanoes, eliminating some of them, and on the other - to replenish this list at the expense of new volcanoes. In our opinion (see below), the Kamen, Ostry Tolbachik, Bolshaya Udina, Uzon, Tsentralny Semyachik volcanoes, Bourdy, Dzenzursky, and the one-act New Tolbachinsky volcanoes represented by slag cones should not be considered active. It is proposed to expand the range of active volcanoes in Kamchatka by including the volcanoes Townschitz, Khodutka, Dikiy Greben and Khangar.

Townsch Volcano is located within the Eastern volcanic zone. He was active in the early Holocene, and about 8500 (7700 14 C) n. a catastrophic eruption occurred on the volcano with a collapse of the cone slope and the formation of a summit crater 1.5 km in diameter. After the eruption an extrusive dome appeared in the crater. It was associated with a strong eruption, which took place around 2400 BP, during which pyroclastic and lava flows were formed. The current period of rest of the volcano (the last 2400 years) does not exceed the maximum duration of such periods (3000-3500) for other volcanoes, which then resumed their activity. As a result, we propose to refer Townschitz to active volcanoes (a subgroup of potentially active volcanoes).

Khodutka volcano in South Kamchatka was active in the Holocene. About 2900 (2800 14 С) ln at the foot of the volcano, a powerful eruption occurred with a product volume of 1–1.5 km 3, during which the Khodutkinsky “Maar” crater was formed. The eruption of the volcano itself took place 2000-2500 14 C ln., When the outpouring of lava flow from its central crater occurred.

Within the framework of this issue, the Wild Crest volcano located on South Kamchatka east of Kuril Lake is of great interest. The construction of the volcano consists of the main extrusive dome (Unpleasant) and several extrusive domes on its slope with lava and pyroclastic flows. Wild Crest is the largest extrusion facility in the Kuril-Kamchatka region. The volcano began to form immediately after the formation of the caldera. Kurilskoye Lake-Ilinskaya ~ 8500 (7700 14 C) ln. . The second phase of activity took place ~ 4800 (4300 14 C) ln. The last eruption of the volcano occurred only 1500 (1600 14 C) ln. (see figure 1). Volcano Wild Ridge has never been viewed by anyone as acting. However, based on the fact that the last period of rest is only 1600-1500 years, it can be classified as potentially active. It was in the activities of the Wild Ridge that the longest (3500) rest period between the moments of activation was found.

Recently obtained data allow to refer to the active volcano Khangar in the Sredinny ridge of Kamchatka. Its youngest eruptions took place only 1000 and 400 years ago.

According to the data of tephrochronological studies, it was established that such Kamchatka volcanoes as Vilyuchinsky, Bakening, Kozelsky and, possibly, Kamen, acted only in the early Holocene. However, since then for more than 7000 years they have not shown volcanic activity, and we believe that they should not be attributed to the current ones. V.A.Ermakov's statement about the directed explosion on the Kamen volcano of the 6th-11th centuries AD is erroneous. In fact, on the Kamen volcano about 1000 ln. there was a giant collapse, subsynchronous to the last but one catastrophic eruption of the nearby volcano Bezymyanny.

In some volcanoes placed in catalogs, in the absence of known historical eruptions, the presence of solfatara activity serves as a basis for attributing to the active ones. However, it should, in our opinion, be distinguished from the actual fumarole activity of the volcano from the solfatar activity associated with hydrothermal activity, which is manifested in the volcano and in its surroundings. Thus, the hydrothermal and solfatara activity of the Late Pleistocene caldera of Uzon, in the Central Semyachik region (the Late Pleistocene Buryashky volcano) and the Middle Pleistocene Dzendzur volcano, is not directly related to the activities of these long-extinct volcanoes. Hydrothermal manifestations here, as in the Valley of Geysers and on Pauzhetka, are confined to large-volume cooling centers of acidic magma of caldeforming eruptions of the Middle-Late Pleistocene stages.

As for the Uzon volcano itself (Marani Pik) on the NW side of the Uzon caldera, it is even older than the caldera of the same name, and ceased its activity at least in the middle Pleistocene. But the youngest volcanic formation in the Uzon caldera is the Maar Lake Faroe, which emerged ~ 7600 14 С ln. .

Allegedly, according to the observations of the hunters, on the heavily destroyed, with typical Alpine relief, the Middle Pleistocene volcano Dzendzur eruption ("during the February 1923 earthquake of Zenzur burned") is very doubtful, since no trace could be detected by anyone. It was probably an ordinary seismotectonic collapse in one of the cars, which are a lot on the Dzendzur volcano, which is also indicated by the synchronicity of the “eruption” of 1923 with an earthquake. One of the last researchers who worked there, Yu.P.Masurenkov, does not mention the eruption.

In this regard, the Kamen, Bourshayuschy, Zenzur, Volcano and Uzon caldera, which are available in catalogs, should be excluded from the list of active volcanoes.

There are no sufficient grounds for referring to the Late Pleistocene Volcanoes Ostry Tolbachik and Bolshaya Udina as active [by 14]. The 6 slag cones on the western slope of Ostry Tolbachik, cited as an appropriate argument, are connected not with this volcano, but with the Holocene regional zone of slag cones superimposed on it. Convincing evidence of the young (1-3 thousand years) age of the last eruptions of the Big Udina volcano is not available.

In our opinion, concrete one-act volcanic forms (slag and lava cones, craters, maars and explosion funnels, extrusive domes), including those that arose in historical time, cannot be attributed to the current ones, because, even by definition, they cannot erupt again in the future.

However, the fields of the Late Pleistocene-Holocene basaltic areal volcanism of Southern and Eastern Kamchatka, as well as the Sredinny Range, can be considered as potentially active, since volcanic forms (slag and lava cones, craters) in many of them arose during the entire Holocene. Therefore, we cannot exclude their education there and in the future.

It is proposed to include in the potentially active and Tolbachi regional zone of slag cones, which arose at the beginning of the Holocene and remains very active up to the present. The youngest volcanic manifestations took place there in 1740, 1941 and 1975-1976. . There is no doubt that new one-act volcanic forms of different types will begin to appear here and in the future.

One of the eruptive centers of the 70-km arc-shaped in terms of linear stretch zone, with which the Tolbachi regional zone of cinder cones is associated, is the apical part of the Flat Plosky Tolbachik volcano. Evidence of this is, in particular, the multi-center Large Fissure Tolbachik eruption (BTTI) of 1975-1976, during which a Hawaiian-type caldera of size 17.17х1180 m and volume of 0.347 km 3 appeared on the top of Plosky Tolbachik. Its appearance here is, in our opinion, a reaction to the outflow of magma from the volcano built into the area of ​​the Southern Breakthrough of the BTTI, where it poured out, forming an extensive (35.87 km 2, volume of 0.968 km 3 across the lava cover). the cone-shaped late Pleistocene stratovolcano of the Holocene stretch zone and a powerful injection of basaltic magma along it contributed to the emergence of Hawaiian-type calderas on top of the last and earlier Hawaiian type, extending its active life to the present and the name Plosky Tolbachik. as being located near the same type and the same age with Flat Ostry Tolbachik, not affected by this crack, it ceased its activity at the end of the late Pleistocene-early Holocene.

Being confined to a single structure formally allows Plosky Tolbachik to be combined with the Tolbachinsky regional zone of slag cones, but this is not prevented by the difference in the peculiarities of their eruptive activity. The activities of Plosky Tolbachik (the same location of the eruption center, the unified eruptive apparatus - the caldera complex and the multiplicity of eruptions) correspond to the activities of a normal multi-volcano, the eruptive centers of the Tolbachinskaya zone constantly migrate, and the resulting volcanic forms are always one-act. Therefore, we consider these formations as independent, although closely related to each other.

The situation is more complicated with the Tolbachinsky single-type, but multi-phase regional zone of the Slab cones of the Flat knolls, which began to form in the late Pleistocene. We know so far the last episode of mass lava effusions (eruption center Lava Shish and others) and caldera formation at the top of the Ploskaia Dalnyaya Sredka volcano (Ushkovsky) occurred here about 9 thousand years ago. Later (but not known exactly when) a shield-like volcano with two cones mounted on it grew in the 4-km caldera of the Hawaiian type that arose then. In the crater of one of them, in 1980, fumarole activity was discovered and first described. Based on this volcano Flat Dalniy (Ushkovsky) received the status of the current. Previously, he was considered only I.Guschenko, however, on the basis of the unreliable information of the entomologist O.Herts about its eruption in 1890. As for the rest of the regional zone of the Slag cones of the Flat hills, the question of its potential future activity, before special studies remains open.

Finally, another field of potentially active volcanic formations can be a field of concentrated manifestation of a multi-outlet (\u003e 15 domes) extrusive volcanism of the Big Semyachik. The formation of very fresh extrusive domes here occurred, probably, during the entire Holocene. However, unfortunately, only some of them have been dated so far: the Ivanov Dome is older than 7900 14 С years (8500-9000 14 С л.н.), the Hedgehog and Crown domes are younger than 5600 14 С years. Therefore, the assignment of this field of extrusive volcanism to potentially active is done, to a certain extent, arbitrarily. For the final solution of the issue, additional special studies are needed.

The result of our conclusions and ideas about active and potentially active multi-volcanoes and other volcanic formations is reflected in Table 2. We hope that the obtained data can be used in compiling a new, modernized version of the catalog of active volcanoes in Kamchatka, as well as for a long-term forecast of volcanic activity, catastrophic eruptions and associated hazards.

It should be noted that the list of volcanic formations proposed by us is not definitive and indisputable. Naturally, it can be changed and supplemented as new materials are received on this issue. And, for most types of volcanic formations, including multi-volcanoes. For example, the Priemysh cone and the Bastion dome [20 each] in the Dzenzur-Zhupanovskaya group of volcanoes in Eastern Kamchatka may be likely candidates for replenishing the list of the latter.

This work was supported by the Russian Foundation for Basic Research (grant 00-05-64299 a, 05-15-98611 l).

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