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 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.

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.

Through radiocarbon techniques we determir the age (30 000 yrs) of the latest in the Late Pleistocene directed blast at the Avachinsky volca and approximately calculated the age of the previous large catastrophic eruption of the same type (35 00( 40 000 yrs). Coarse debris deposits produced by the eruption originally covered the area of 400 km2 a their volume was 16-20 km3. As a result of these eruptions the relief cardinally changed to the south of t Avachinsky and the lower part of the Avacha river channel was transported to the distance of 6-10 km. 11 believed that in the nearest hundreds of years such blasts will not take place but this forecast does not apply the adjacently located Koryaksky volcano.

The 1645 B.C. oxygen peak in Dye 3 borehole (65.18 N, 43.49 W) drilled in the Greenland ice sheet is shown to have been the catastrophic caldera-generating Aniyakchak eruption (56.88 N, 158.17 W) on Alaska Peninsula, U.S. rather than the famous Minoan eruption (36.404 N, 25.396 E) on Santorin Island, Greece.

We studied the tectonic setting, morphology, geological structure, the history of eruptive activity and the evolution of the composition of the erupted material of Kizimen volcano (Kamchatka) from the moment of its origination (12-11 thousand years ago) to the present time. Four cycles 2-3,5 thousand years long each were distinguished that characterize the activity of the volcano. All largest eruptions were dated, their parameters determined. We also estimated the volume and the mase of the erupted products, volcanic intensity of evacuation of material during-periods of high activity and productivity of the volcano at different stages of its formation. It has been shown that evolution of the composition of the rocks erupted (from dacite to basaltic andesite) takes place as a result of mixing of dacitic and basaltic magma. It is proposed that future eruptions that may take place at Kizimen will be similar to those at Bandai (1888) and Mount St. Helens (1980) volcanoes.