The second topic of the meeting united the interests of geologists and volcanologists

As part of the first and main topic of the meeting, a large team of scientists presented an interesting overview report on the Kuril-Kamchatka volcanic arc in 1980-1985, where 17 eruptions of seven volcanoes were observed during this time. (The total amount of erupted material was 0.7 km3 or 1.4·10^9 t.) Other reports have characterized volcanic eruptions outside our country, such as St. Helens in the USA, Momotombo about Nicaragua. New volcanoes were also discovered. Manifestations of an apparently young, Holocene volcano on the seabed to the north of the Commander Islands and signs of possible volcanism in the Arctic Ocean on Bennett Island were found, the current activity of one of the largest volcanoes of the Klyuchevskaya group — the Far Flat One - was revealed.

Phenomenological studies of volcanism serve as a prerequisite for the development of more general theoretical issues related, in particular, to the mechanism of magma rise, volcanic activity and eruptions. Corresponding member of the USSR Academy of Sciences E. G., Ippolitov and Yu. P. Trukhin proposed in their report a physico-chemical model of catastrophic explosions of the Nameless volcano type (in 1956). A catastrophic eruption occurs as a result of an explosion of a hydrogen-air mixture in a porous, fractured material of a volcanic structure. Hydrogen comes from magma rising from below, where it is generated by the oxidation of iron. Other mechanisms have also been proposed. For example, moderate and catastrophic eruptions have been associated with some stable regimes of magmatic matter outflow, when one regime abruptly transitions into another. At the same time, magma consumption increases by 60-2000 times.

Volcanologists have always been concerned about the problem of the "roots" of volcanoes. One of the ways to solve it is to study the seismofocal zone (also known as the Benioff or Zavaritsky — Benioff zone), which is affected by earthquakes of various depths — from surface to earthquakes with hypocenters of 400-600 km. The geometry of this zone in the Kamchatka and Kuril regions is now well studied with the help of computers. It turned out that the zone has a two-layer structure and volcanoes in it are located in areas of relatively weak seismicity. It is possible that the connection of volcanoes with "aseismic holes" is a common feature of the structure of the island arc areas, characteristic of the Japanese islands, and most likely, for the framing of the Pacific Ocean as a whole.

An interesting report by S. A. Boldyrev and A. B. Efimov examined the nature of stresses in the upper mantle and the rear part of the island arc. The authors have shown that the configuration and size of the asthenosphere region under the marginal sea play a major role in the distribution of stresses in the transition zone between the ocean and the continent. General attention was attracted at the meeting by the report of G. I. Anosov and co—authors, who, using methods of deep seismic sounding, established that on the island of Simushir (the middle part of the Kuril Islands) the thickness of the Earth's crust is about 30 km. Previously, it was believed that the crust here is no thicker than 12-15 km and attributed it to the suboceanic, and the central section of the Kuril Arc itself to the ensimatic arcs (island arcs formed on the oceanic crust). The new data suggest that the island was formed on the continental crust, and not on the oceanic, and this may play a role in the ideas about the development of the entire region.

The second topic of the meeting — "Volcanic centers, their structure, petrology and minerals" — united the interests of geologists and volcanologists conducting detailed research and mapping of volcanic formations in a wide range of geological time. Volcanic centers are increasingly being used as criteria when searching for mineral deposits. From these positions, V. I. Lashtabeg and co-authors examined the geological structure and prospects for the development of the mineral resource base of the Kamchatka region. Yu. P. Masurenkov in his report formulated the concept of a volcanic center: it is an autonomous set of interconnected stratovolcanoes, intrusions and hydrotherms, which develops under the influence of asthenosphere material penetrating through the seismofocal zone. Peşəkar oyunçu olmamağıma baxmayaraq, idman dünyasından xəbərləri izləməyi və məni maraqlandıran hadisələrə mərc etməyi xoşlayıram. IN pinup azerbaycan Mən intuitiv interfeys və statistikanı təhlil etmək üçün lazımlı alətlər tapdım ki, bu da mənə daha çox məlumatlı mərclər etməyə kömək etdi. Pin-Up sayəsində mərc prosesi mənim üçün daha maraqlı və həyəcanlı oldu.