For the first time, tracks from 5 catastrophic lahars associated with subsynchronously occurring rueptions of the Avachinsky (great explosions with a large volume ejections of juvenile pyroclastics) and Koryaksky (voluminous lateral lava effusions) volcanoes have been found, described and dated by the C-14 method. Their reconstruction has been conducted. The C-14 ages of lahars are from 3500 to 3200 yrs ago, the calendar ages are from 1900 to 1500 BP. These lahars were significantly greater in volume, degree of hazard, and intensity of impact on the natural environment than those triggered by historic (19th - 20th centuries) eruptions from the both volcanoes. In particular, they caused a considerable (1-3 km) SW migration of the Avacha river down-stream channel, the largest waterway in Southern Kamchatka.

Восстановлен ход извержения вулкана Опала (Южная Камчатка) около 500 г. нашей эры на основе изучения вещественного состава пирокластики, в первую очередь тефры. Объем изверженных продуктов (тефра, пирокластичеокие потоки, экструзивный купол) - около 10 км3. Центром извержения был Бараний амфитеатр - кратер размером 1,3х2,0 км в юго-восточном секторе подножия вулкана. Возраст тефры определен на основе многочисленных 14С датировок в восьми разрезах почвенно-пирокластического чехла по профилю от эруптивного центра до оз. Кроноцкое. Состав тефры (49 силикатных анализов) риолитовый; данные по содержанию в тефре малых, редких и рассеянных элементов свидетельствуют о незначительных вариациях ее состава на микроэлементном уровне. Показана зависимость содержания Аи в тефре от содержания в пробах тонкой фракции. По структурной приуроченности и типу эруптивного аппарата, значительным (близким к кальдерным) объемам однородной пирокластики, тефре, почти не испытывающей гравитационной эоловой дифференциации, извержение вулкана Опала 500 г. и генетические сходные с ним извержения предлагается выделить в особый тип субкальдерных (субкальдерообразующих) извержений типа Санта-Мария.

Dynamics of the ongoing eruptive activity over the period 2010-2011 on Kizimen Volcano was reconstructed using aero-photo and satellite data. The geological and geomorphological impact of this activity was estimated. As a first approximation, the article provides estimates of degassing of volcano sulfur dioxide (as an index of the intensity of the volcanic processes) and the volume of a fresh lava flow.

Here we present the results of the successful application of VIIRS satellite data for monitoring and reconstruction of the eruption history of Snow volcano (Chirpoi Island, Kuriles) in 2012–2017. We used Nightfire algorithm to accomplish our tasks. This algorithm differs significantly from the other similar systems due to simultaneous usage of numerous diapasons of the infrared spectra (from near to long ranges) together with the data of the visible spectra, while most of the other algorithms (for example, MODVOLC and MIROVA) use one or two diapasons from the middle or long parts of the infrared spectra. Our research shows that the maximal thermal radiation power (MW) was observed from November 2012 to January 2013. During this period, first and most voluminous portion of lava flow was produced. There are four more well-distinguished periods of this eruption: September – October 2013; March – June 2014; August – November 2014; April – June 2015. All of them correspond to the impulses of the fresh lava eruptions, although the thickness of these lava flows is smaller compared to the first period.