Consequences of the Ebeko eruptions in 17-20 centuries were reconstructured in detail based on history information and data of tephrochronoSogical investigations and air photography of 1960, 1987, 1988, 1990. It is shown that all the eruptions were phreatic and conditionally phreatomagmatic with thermal alimentation as a very heated dike-sill complex with volume of more than 1 km , in the zone of extension NNW (Az. 25°), where volcanoes of the Vernadsky ridge are located (Paramushir island). It is supposed that the main future hazard for the Severo-Kurilsk town and the nearest areas is expecting from the moving of lahars of large-volume along the Kuzminka and the Matrosskaya rivers originated from the Ebeko volcano. Lesser hazard is expecting from ashfalls produced by the Ebeko and other volcanoes of the North Kuril and the Souih Kamchatka. It is proved that a big hazard for the may arise from the future eruption of the Ebeko similar to those eruptions of 1934-1935. It is recommended some ways for defence of the town.

This paper presents results of a specialized analysis applied to deposits reached at site 193 which was drilled during the 19th cruise of the drillship Glomar Challenger in the Pacific Ocean east of the Central Kuril Islands. These data can serve as a basis for the initial phase of future submarine tephrochronologic surveys in the area. Special attention was paid to layers, lenses, and spots of tephra of varying composition and thickness, as well as to sediments having a higher admixture of volcanic glass particles. It was found that at least 8 ashfalls have occurred in the area of site 193, of which 7 took place during the last 115 ka. It is shown that these were more likely related to large and caldera-generating explosive eruptions at volcanic centers in the Kuril Islands. Preliminary dating of these has been carried out. For the first time, a core sample was identified to contain turbidite due to a hypothetical submarine earthquake that occurred in the Early Holocene. We suggest a hypothesis to explain why the sea sediment core samples are disrupted, hypothesizing that thick interbeds of water-rich pyroclastic material of aleuropelite dimension were converted to hydrosols by thixotropy.

This study revealed that the giant cirque of Bakening Volcano had been produced by its eruption ca. 8000-8500 carbon-14 year ago. The eruption is supposed to have been heralded by a large earthquake (M > 7) resulting in the collapse and slide of the SE sector of the cone. The landslide unroofed the hydrothermal system and triggered an explosion which was followed by an ash-and-block pyroclastic flow. A rockslide avalanche rolled down into the valley of the Srednyaya Avacha River and travelled as far as 10-11 km along it. The avalanche deposited its debris material over an area of 18-20 km2 measuring 0.4-0.5 km3 in volume. These deposits dammed the river, produced two lakes (Bezymyannoe and Verkhneavacha), and gave birth to a large lahar which traveled along the valley much farther.

В работе впервые рассмотрен широкий круг вопросов, связанных с историей развития рельефа Курило-Камчатсхой области. Проводится анализ истории образования различных типов морфоструктур в новейшее время. Особое внимание уделено анализу динамики образования морфоструктур под действием тектонических процессов и специфике формирования рельефа вулканических областей. Выделены основные тектонические эпохи.

Abstract-This study is the first to show, using data from the eruption of Koryakskii Volcano, Kamchatka that began in December 2008 and continued through 2009 that the water in permanent and temporary streams that start on the slopes of the volcanic cone and in temporary lakes when contaminated with fresh tephra is a specific hazard factor related to long-continued hydrothemial-phreatic eruptions on that volcano. This water is characterized by increased acidity (pH 4.1-4.35) and large amounts (up to 50-100 cm /liter) of solid suspension and is unfit for drinking and irrigation. When combined with tephra, it probably produced mass destruction of a number of animals who lived on the slopes and at the base of the volcano. The water contaminated with tephra is an important component of the atmospheric mud tlows occurring on Koryakskii Volcano; for several future years it will be a potential source for enhancing the acidity of ground water in the volcanic edifice.

В результате геолого-геоморфологических и тефрохронологических исследований одного из самых активных в Центральной Америке вулкана Момотомбо (Никарагуа) с целью оценки вулканической опасности построенной у его подножия ГеоТЭС, была восстановлена история формирования вулкана с момента его возникновения (4000-4500 лет назад) до настоящего времени. Крупнейшие извержения вулкана датировались МС методом, было прослежено площадное распространение тсфры, оценены объем и масса изверженных пород в целом и по отдельным эруптивным этапам. Проведенные исследования позволяют заключить, что все сооружения ГеоТЭС находятся в опасной зоне, а наибольшая опасность может быть связана с выпадением тефры. До конца XX века может произойти извержение с объемом материала порядка 50-100 млн. м3. В зависимости от ориентировки выбросов, скорости и направления ветра мощность тефры в районе ГеоТЭС может быть в пределах 20-150 см.