Records of microbarographic instruments in the near zone (45 and 113 km) were used for a detailed analysis of wave disturbances in the atmosphere accompanying the November 12, 1964 Shiveluch eruption. It is shown that the wave disturbances due to this major explosive eruption were largely caused by the formation of a convective column; they provide information on the time history of the eruption and the amount of erupted ash. The relation between seismic and acoustic intensities shows that the eruption started with a giant landslide (1.5 km3) giving rise to an ash cloud that produced the first acoustic signal. Volcanic tremor began 12 min after the slide and a second acoustic source began operating. This was related to starting Plinian activity and eruption of pyroclastic flows. The transition from one phase of the eruption to the next was accompanied by increased volcanic tremor and acoustic signal component of frequency > 0.05 Hz, as well as by generation of a long period (greater than 10 min) disturbance having an excess pressure of 50 Pa at 113 km distance. The amount of ash ejected into the atmosphere as inferred from long period disturbance energy is estimated to be 0.35-0.45 km3, which is in satisfactory agreement with geological evidence (0.3 km3).

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.

Resuspended ash is common in the areas of active volcanism and can be dangerous for ecosystems, human being and animals, different means of transport including local aviation. According to KVERT scientists data, a formation of resuspended ash plumes on Kamchatka occurs in the area of Sheveluch volcano annually, mainly from August to mid-October within two days. For example, these plumes observed on August, 3, 2011, September, 15–16 and October, 3–4, 2015, September, 28–29 and October, 2–4, 2016. Dense ash plumes rising 3 km above the surface to a.s.l. and 16–22 km in width drifted 600 km to the south-east from the volcano. Analysis of various satellite data in the VolSatView information system revealed typical features of Sheveluch resuspended ash plumes. The largest concentration of ash particles is observed in ash plumes at a distance of 60–70 km from the volcano; its width on the land for over 100 km reaches 16–22 km and is 1–2 km thick from the earth’s surface; a wide ash-rich plume is retained in the atmosphere from 3–5 hours to several days.

Owing to modern development of information technologies and computer simulation systems, and datasets derived from open historical meteorological data archives, it appeared possible to perform retrospective analysis of large explosive volcanic eruptions. This work analyzes the results of simulation of the events associated with the eruptive cloud propagation during the catastrophic eruption of the November, 1964 Sheveluch volcano. The obtained additional eruptive cloud parameters enabled us to reproduce the dynamics of the explosive eruption and to validate its magmatic genesis.