The first historical eruption of Kambalny volcano began on March 24, 2017 with the powerful ash emission from the summit crater reaching as high as 6 km above sea level. The explosive activity continued without interruption from March 24 to March 30. The most powerful ash emission was registered on March 25–26, when the ash plume drifted several thousand kilometers SW, S, and SE from the volcano. On April 2 and April 9, after several calm days, powerful ash explosions occurred generating ash plumes up to 7 km high. The area of the land and sea over which the ash plume drifted during the day of March 25, was 650000 km2; the area of the ash accumulation on the land that was formed from March 24 to April 9, exceeded 1500 km2. These parameters were measured using the satellite-based data in the VolSatView information system. Domination of the silty fraction and the presence of secondary minerals (pyrite, gypsum, sulfur, and others) in the ash point to the phreatic character of the volcanic eruption.

Airborne volcanic ash is one of the most common, far-travelled, direct hazards associated with explosive volcanic eruptions worldwide. Management of volcanic ash cloud hazards often requires coordinated efforts of meteorological, volcanological, and aviation authorities from multiple countries. These international collaborations during eruptions pose particular challenges due to variable crisis response protocols, uneven agency responsibilities and technical capacities, language differences, and the expense of travel to establish and maintain relationships over the long term. This report introduces some of the recent efforts in enhancing international cooperation and collaboration in the Northern Pacific region.

AAbstract—Numerous summit and parasitic eruptions of moderate potassium magnesian and high-alumina basalts and basaltic andesites, their mineralogic and geochemical features, and the composition of in situ chilled melt inclusions in the olivine of cinder lapilli discharged by Klyuchevskoi Volcano all provide evidence of the presence of magma chambers beneath the volcano. This is also supported by a dualism in the variation of CaO and A1203 concentrations in olivine and clinopyroxene during crystallization. The mineralogic features in the high-alumina basalts that were discharged by all parasitic eruptions of Klyuchevskoi provide evidence of magnesian magma being emplaced from a deeper chamber into a shallow high-alumina chamber. The distribution of incoherent elements in the volcano's magnesian and aluminiferous rocks shows that they came from a single mantle source. The geochemical and mineralogic data are in good agreement with the results of geophysical surveys that concern the structure and properties of the lithosphere beneath Klyuchevskoi.

An analysis of local seismicity within the Klyuchevskoi Volcanic Cluster and Shiveluch Volcano for the period 2000–2017 revealed a sequence of plane-oriented earthquake clusters that are interpreted here as the emplacement of dikes and sills (magmatic fracking). The geometry of magma bodies reflects the geomechanical conditions in volcanic plumbing systems and at the bases of the volcanoes. Magmatic fracking within active magmatic plumbing systems results in the formation of permeable reservoirs whose vertical extent can reach 35 km (Klyuchevskoi) and can be as wide as 15 km across (Shiveluch), depending on the geomechanical condition of the host rocks. These reservoirs will be the arena of subsequent hydrothermal circulation, producing geothermal and ore fields, as well as hydrocarbon fields. TOUGH2-EOS1sc simulation tools were used to estimate the conditions for the formation of hydrothermal reservoirs at temperatures below 1200°С and pressures below 1000 bars.

Clusters of small-volume volcanoes that individually may be defined as monogenetic, but have interlinked and
interconnected plumbing systems, are used to be categorized as monogenetic volcanic fields (MVF).We argue
that such volcanic clusters should be distinguished as separate type of volcanism, intermediate between monogenetic and polygenetic. The magma plumbing system structure of the MVF (its complexity and polymagmatic
character) is the key argument for the potential separation of themin a classification. To avoid confusion caused by geneticmeaning of the used words we suggest using a term “areal volcanism” or “areal volcanic fields” (AVF instead of MVF) as defining this special type of volcanic activity. Herewe provide a reviewof themain characteristic features of one of the largest Holocene AVF, which is active now – the Tolbachik field of cinder cones in the southern part of Klyuchevskaya volcano group (Kamchatka), known in the literature as Tolbachinsky Dol. This paper is focused on the research of magma plumbing system. We consider structural,morphological, geological, geochemical and petrological data on the erupted basalts and their genesis. Specially planned seismic experiments made in 2010–2015 (seismic tomography and microseismic sounding) allowedmodeling of the principal elements of the magma plumbing system of Tolbachik AVF. Analysis of the investigations made in this area shows that Tolbachik AVF has a complex, dynamic, variable magmatic feeding system, which can be visualized as a superposition of subvertical and sublateral magma conduits. The contrast composition of the erupted rocks is caused by their different, although genetically connected, magma sources and mixing processes. One of the long-lived eruptive centers of Tolbachik AVF is Plosky Tolbachik stratovolcano, which lost its independent activity and was captured by Tolbachik AVF in Holocene. The AVF formed rejuvenated volcanism using the feeding system of the stratovolcano like an “old anthill”. The magma plumbing system characteristics of Tolbachinsky Dol strongly support the idea of separation of AVF from monogenetic volcanism type in the classification.