Laterally directed blasts are explosive events following a major sector collapse of a volcano, with the potential for devastating areas of several hundred km2, due to powerful dilute and turbulent pyroclastic density currents. The catastrophic flank collapse on 30 March 1956 of Bezymianny (Kamchatka, Russia) was the climactic phase of the first historical magmatic eruption of this volcano, after 1000 years of dormancy. Magma stored in a cryptodome was depressurized by a sector collapse, generating a laterally directed blast immediately followed by pumiceous concentrated pyroclastic density currents. By combining petrological data from Bezymianny plumbing system and temporal constraints from orthopyroxene, magnetite, and amphibole chronometers, we tracked magmatic processes over twelve years prior to the eruption, followed by magma ascent to a shallow reservoir and a heating process at least three months before the eruption. Magma was last stored in a cryptodome at least two months before the climactic phase of the eruption. Evidencing magma dynamics of a few months to a few years before major flank collapses and laterally directed blasts thus represents valuable information for volcanic risk mitigation (as it also occurred at Mt St. Helens).

The gravitational instability and subsequent lateral collapse of a volcano is a common phenomenon observed in most types of volcanoes, from continental to oceanic environments. Both intrinsic and extrinsic factors contribute to volcanic collapse, including the volcano's internal structure, geological setting, and a range of volcanic and non-volcanic processes, including climatic conditions. Lateral collapse typically leaves a scar on the volcano's flank and produces a corresponding debris avalanche deposit. Debris avalanched deposits are characterized by distinct morphological features and internal facies that can reveal the causes of the instability and the interaction of the failure mass with the surrounding substrate and landscape. Lateral collapses can trigger secondary hazards such as magmatic and phreatic eruptions, tsunamis, lahars, river obstructions with the formation of natural dams, and submarine landslides, leading to potentially catastrophic environmental effects. Studying volcanic landslides is fundamental for improving our scientific knowledge of this geological process and understanding their associated hazards in the short and long term. Such knowledge can enhance social awareness, promoting urban resilience and ecosystem protection.

Volcanic mineral texture and compositional zoning offer crucial insights into magmatic processes and their timing preceding an eruption. Each mineral may capture different aspects of the pre-eruptive magmatic processes. Here we use a multimineral (plagioclase, orthopyroxene, and magnetite) approach to decipher the magma dynamics prior the 2010 magmatic eruption of Kizimen volcano (Kamchatka). The eruption comprised explosive episodes generating pyroclastic density currents followed by the extrusion of a thick lava flow. We combined crystal system analysis with diffusion chronometry on plagioclase and magnetite, together with the orthopyroxene data of Ostorero et al. (3:290, 2022). Plagioclase crystals record up to four different magmatic environments which include two distinct magma mixing events. The first one involved the injection of mafic magma into an initially dacitic reservoir. The magma intrusion led to significant environmental changes within the reservoir which became thermally and compositionally zoned, with remnant dacitic magma at the top and newly created andesitic magma at its base. Both plagioclase and orthopyroxene record the interaction between the dacitic and andesitic magmas during a second mixing event at their interface. This event can be linked to a seismic crisis approximately 1.5 years before the eruption, and is also recorded by Fe–Mg diffusion chronometry in orthopyroxene. Magnetite zoning recorded a final heating event of a few days, potentially marking magma ascent and storage in the lava dome. The compositional zoning plagioclase and magnetite crystals is consistent with the spatio-temporal interpretations made from orthopyroxene crystals zoning and timescales. Plagioclase serves as a reliable yet more complex archive compared to orthopyroxene. Correlating different mineral records enables a more precise reconstruction of magmatic history. Combining petrological and monitoring data provides a more robust understanding of pre-eruptive reactivation.

Bezymianny volcano (Kamchatka, Russia) is an andesitic island arc stratovolcano that started to erupt in 1955 after 1000 years of dormancy. On March 30, 1956, the climactic phase of the eruption was preceded by a 4-month-long emplacement of a shallow cryptodome, which triggered a flank collapse violently decompressing the magma into a laterally directed blast followed by an explosive phase emplacing extensive pumice concentrated pyroclastic density currents (pumice C-PDC). Aiming at constraining the plumbing system below Bezymianny volcano prior to the 1956 eruption, we performed a multiphase textural and petrological study using dense to vesiculated clasts of the blast and pumice samples from the post-blast C-PDC deposits. We inferred the pressure and temperature conditions of magma storage using sample vesicularity, amphibole destabilization rims, volatile contents in melt inclusions, microlite textures, and phase compositions (phenocrysts, microlites, and glasses). We propose a three-level magma storage characterized by a deep reservoir (≥ 200–350 MPa, ≥ 840 °C, 4.0–8.0 wt

Pyroclastic density currents (PDCs) are a major volcanic hazard, whose variability of triggering and deposition mechanisms suggests highly complex and different initial states to be considered. Here, we describe block and ash flow deposits from the March 2019 eruption of Bezymianny volcano, Kamchatka. Ash clouds from this eruption extended into the Pacific Ocean, while block and ash flow deposits were found widely across the slopes of the edifice. We use satellite and drone-based photogrammetry to show material dispersal and accumulation during the eruption. We also use these photogrammetric data to obtain basic granulometry, suggesting dominantly 60 cm block dimensions, some exceeding 2 m in scale, embedded in a fine ash matrix. In addition, we sampled the deposit and herein demonstrate how distinct petrographical features can be used to distinguish the type of block and ash flow. Deposit characteristics, density, dimension, and petrography suggest that PDC initiation occurred during an eruptive episode conventionally considered as a “boiling over” event. This activity is characterized by rapid magma volume expansion due to intense gas exsolution which is driving a frothed mass out of the vent leading to the formation of large but highly vesicular juvenile blocks. Such an eruption style is transitional between effusive (lava dome forming) and explosive activity, and we suggest a new term “effervescent fountaining” to replace the term “boiling over” as a more appropriate description of such an eruption. Material dispersal, density of juvenile material, and Fe-Ti mineralogy are useful features to distinguish different types of block and ash flow deposits. These characteristics are also applicable to deposits from eruptions and deposits within the prehistoric geological record, improving our understanding of historic eruption patterns.

The mineralogy of volcanic rocks is usually considered as a consecutive crystallisation path related to a liquid line of decent. Tephra and pyroclastic rocks hold a special status as their formation includes the physical disruption of the magma during an explosive eruption. We describe tuffisite samples (captured veins of pyroclastic material in coherent lava bombs) and concurrently ejected volcanic ash from the ongoing eruption of Ebeko Volcano, Russia. Our samples show that tridymite (a mineral, not present in the original phase assemblage of the magma) forms as a consequence of explosive eruptive activity, volatile exsolution and fluid flow following decompression and magma fragmentation. Vapour phase crystallisation (VPC) of cristobalite is well known from highly evolved, dome-forming eruptions due to gas flux through highly permeable and porous glassy dome rocks. At Ebeko volcano, increased permeability develops in the volcanic conduit during magma fragmentation and transient tephra storage. Magmas erupted at Ebeko are less evolved than those of typical (dome-forming) andesitic - dacitic Pel & eacute;an eruptions and show comparably higher eruption temperatures favouring the formation of tridymite over cristobalite during VPC.

This article explores the NIMBY (Not In My BackYard) phenomenon in urban planning conflicts in Novosibirsk and Irkutsk. It focuses on residents' resistance to construction or other changes to infrastructure near their homes. In Western science, NIMBYism is typically viewed as a negative phenomenon that hinders territorial development or leads to adverse social outcomes, such as obstacles to building affordable housing, roads, social infrastructure, and green energy projects. The NIMBY phenomenon has been scarcely studied in Russia. The prevalent approach views urban activists as opposing stronger coalitions of city authorities and developers. Under this approach, the interests of local residents are seen as systematically compromised or outright ignored in urban planning. However, using data from expert interviews (N=40) and qualitative and quantitative event analysis of media sources reconstructing the history of urban conflicts in the cities over the last 18 years, it has been shown that civic activists are not always the "weakest link". They may be supported by representatives of the city administration and other influential agents including governors, prosecutors, the Investigative Committee, and the Presidential Administration. In such circumstances, small groups of activists can halt not only commercial developments but also socially significant non-commercial projects. The article concludes that the interests of a wide range of stakeholders must be considered, as NIMBYism significantly complicates the reaching of a compromise in conflict resolution.

The ash fallout of Shiveluch volcano (April 11, 2023, Kamchatka) is the most intensive volcanic ash fallout of the last 60 years. We present the results of the reconnaissance fi eld investigations supplemented with analyses of satellite images of the area for estimations of deposits distribution and area aff ected by the ash fallout. We also estimated the properties of fi ne grained ash of andesitic composition and its infl uence on the forest vegetation composed by Picea yezoensis (Siebold et Zucc.) Carrière, Larix cajanderi Mayr и Betula ermanii Cham. As a result of moderate- scale ash fallout in the forest (thickness of freshly deposited ash is 5–8 cm), the negative impact on vegetation was minimal because the ash was fi ne-grained and was deposited on a thick snowpack, and the leaves were not formed yet. The forest vegetation on lower elevations was not damaged at all but strong changes occurred in grass and bush vegetation. We have observed the diminished density of plant coverage, decreased size of grass vegetation and a decreased number of plant species. Calamagrostis purpurea (Trin.) Link. s. l., a broadly represented dominant species among grass vegetation, became less common, but Chamerion angustifolium (L.) Holub became more widespread. The possibility of small plants to grow through the ash layer turned out to be strongly reduced. Mosses and lichens in the forest have been buried under the ash, the recovery could take several decades. We have found a notable impact on plants by ash remobilized by strong wind, this impact is the strongest in the open areas and on forest edges. This process can continue for many years due to the large volume of the deposited ash covering the open spaces of the volcano foot.

Geyser geothermal fields are scenic volcanic landforms that often contain tens to hundreds of thermal spot vents that erupt boiling water or contain bubbling mud pools. The fields are potentially hazardous sites due to boiling water temperatures and changes in vent locations and eruption dynamics, which are poorly understood. Here we report on the rapid and profound changes that can affect such a geyser field and ultimately lead to a dangerous, unanticipated eruption. We studied the Geyser Valley, Kamchatka Peninsula, which is a field of geysers and other thermal features and boiling pools. Using high-resolution tri-stereo satellite data and unmanned aerial systems (UAS) with optical and thermal infrared cameras in 2018 and 2019, we were able to identify a newly emerging explosion site. Structure-from-motion analysis of data acquired before and after the explosion reveals morphological and thermal details of the new vent. The explosion site produced an aureole zone of more than 150 m3 of explosively redeposited gravel and clay, a slightly elliptical crater with a diameter of 7.5 m and a crater rim 0.30 m high. However, comparison with archives of photogrammetric data suggests that this site was thermally active years earlier and contained a crater that was obscured and covered by landslides and river sediments. The results allow us to develop a conceptual model and highlight the hazard potential of thermal features buried by landslides and clastic deposits. Sudden explosions may occur at similar sites elsewhere, highlighting the need for careful assessment and monitoring of geomorphological and hydrological changes at geyser sites in other regions.

Mount Iriga is a small, dormant stratovolcano of basalt to basaltic andesite composition located in Luzon Island, Philippines. The volcanic edifice includes a well-preserved horseshoe-shaped avalanche scar 2 km across with an adjacent fan of hummocky debris avalanche deposit (DAD) formed by large-scale (1.5 km3) gravitational edifice collapse. To constrain the age of the collapse and determine the character of volcanic activity that followed, we investigated and dated (using the 14C accelerator mass spectrometry method) paleosoils and organic lake sediments as well as charcoal-containing pyroclastic deposits that closely pre- and post-dated emplacement of the DAD. We found that the collapse of Iriga occurred soon after its 1830 ± 40 BP explosive magmatic eruption (of St. Vincent type) that produced pyroclastic flows of scoriaceous basaltic andesite. In the avalanche-dammed Lake Buhi, the organic bottom sediments started to accumulate at 1780 ± 30 BP, marking the upper age limit of the DAD emplacement. The edifice collapse itself was not contemporaneous with any geologically detectable explosive eruption. After the collapse, a stubby block lava flow with volume of about 0.02 km3 was extruded inside the horseshoe-shaped avalanche scar. The next eruption of Iriga, which was its only post-collapse explosive eruption, occurred at 1110 ± 30 BP. This phreatomagmatic eruption left a small steep-walled maar-like crater inside the broad avalanche scar in the vent area of the block lava flow. The extrusion of the block lava and the subsequent phreatomagmatic event were the only eruptions of Iriga that occurred after the edifice collapse. Together with the pre-collapse explosive eruption, they comprise the entire eruptive activity of Iriga during the Late Holocene and all occurred during the last 2000 years.

Most volcanic eruptions occur through magma pathways that resemble tube-like conduits fed from magma sources at depth. Here we combine remote sensing observations with both analog and numerical experiments to describe the extrusion of a spine at the Shiveluch lava dome, Kamchatka (Russian Far East) in April-October 2020. We show that spine growth is preceded by bulging of the dome surface, followed by extrusion in an asymmetric manner. The spine then elongates along a previously identified fracture line and bends toward the north. By repeated morphology analysis and feature tracking, we constrain a spine diameter of ~300 m, extruding at a velocity of 1.7 m/day and discharge rate of 0.3–0.7 m³/s. Particle modeling of an extruding conduit plug highlights that the spine may have inclined to the north due to the topography and hidden architecture of the subsurface. We suggest that such complexities are rather common, where mechanical heterogeneities in the conduit material, mechanical erosion of the hidden spine buried by the co-evolving dome, as well as topographic (un-)buttressing controls directionality of spine growth and spine instability. The results presented here are relevant for understanding the growth and collapse hazards of spines and provide unique insights into the hidden magma-conduit architecture.

A short-lived but violent explosive eruption occurred on the small volcanic island Raikoke in June 2019 (central Kuril Islands). The culmination of the eruption lasted 3.5 h and the ash cloud rose to a height of 13 km. An analysis of a sequence of satellite images in combination with ground-based observations gave information on the pyroclastic deposits of the eruption and allowed us to estimate the associated impact on the island ecosystems. We found that this eruption had a phreatomagmatic, sub-Plinian to Plinian character. The phreatomagmatic mechanism of the eruption occurred due to interaction between the rising basaltic andesite magma and ground waters, which were mostly represented by sea water that percolated through the permeable rocks of the volcanic island. The eruption produced numerous pyroclastic flows. The hot deposits of the pyroclastic flows and tephra covered the entire island, destroying the vegetation and the habitat of birds and sea mammals. Much of the pyroclasts was deposited in the form of fans of pyroclastic flows at the base of the volcanic slopes, considerably displacing the shoreline seaward. As a result, the island area increased by 15%. The pyroclastic deposits were intensely eroded and redeposited during the first year after the eruption, making new areas of the island coast. The recovery of Raikoke’s ecosystems will be enhanced by erosion of the pyroclastic deposits and gradual resettling of birds, which would bring new plant species to the island. The succession would be accelerated by areas of survived vegetation. Overall, we see periodic dramatic disruptions in the island ecosystems caused by violent explosive eruptions with subsequent rapid recovery that with high probability will be interrupted by new eruption.

The increase in number and intensity of earthquakes during a pre-eruptive crisis is the main basis of seismic volcano monitoring. However, a strong understanding of how these seismic signals relate to magmatic processes in the magma plumbing systems prior to volcanic eruptions is crucial for these efforts. Here we compare the characteristics of a seismo-volcanic crisis prior to the 2010–2013 explosive-extrusive eruption of Kizimen volcano, Kamchatka with the timescales of processes in the magma plumbing system. These timescales are inferred from the numerical modelling of iron-magnesium intracrystalline interdiffusion in 88 zoned orthopyroxene crystals from dacites and silica-rich andesites collected after the eruption. We find that the eruptible magmas were assembled rapidly during a magma mixing process beginning around 1.5 years before the eruption, which is well correlated with the onset of the seismic crisis. We conclude that the observed seismic re-activation marked the onset of magma mixing and led to destabilization of the reservoir, followed by the eruption.

Abstract The increase of number and intensity of earthquakes during a pre-eruptive crisis is the main basis of seismic volcano monitoring. However, the exact relationship between the seismic activity and the volcano-magmatic processes remains unclear. Here we present a direct comparison between characteristics of a seismo-volcanic crisis recorded prior to the 2010-2013 eruption of Kizimen volcano (Kamchatka, Russia) and the timescales of processes in the magma plumbing system. These timescales are inferred from the modelling of Fe-Mg intracrystalline interdiffusion in 88 zoned orthopyroxene crystals from dacites and silica-rich andesites samples collected after the eruption. We show that the eruptible magmas were assembled rapidly during a magma mixing episode ~1.5 years before the eruption, which is well correlated with the onset of a seismic crisis. We conclude that the observed seismic re-activation marks the onset of magma mixing leading to destabilization of the reservoir followed by the eruption after ~1.5 years.

Webcam data showing the growth of a spine at Shieveluch volcano. The data is provided in three formats. First the original images with clear visibility are provided. Second a time lapse movie is provided with images co-aligned to reduce shaking of the camera. Third, a zoom in of the time lapse movie is provided. For more information we refer to the publication with the title "Tracking magma spine extrusion from space: Implications for conduit and topography complexity at Shiveluch volcano, Kamchatka" published in Nature Communications E Env

For the first time, the thermal behavior of a new mineral belomarinaite KNaSO4 from volcanic exhalations (trigonal crystal system, Sp. gr. P3m1, a = 5.6072(3), c = 7.1781(4) Å, V = 195.45(2) Å3) was studied on a natural sublimate sample from the 2012–2013 Tolbachik Fissure Eruption and its synthetic analogue, a low temperature (LT) polymorph of (Sp. gr. P3m1) in the range 30–800°C (high-temperature X‑ray diffraction) and 30–1000°C (DSC and TG). The mineral is stable up to a temperature of 470 ± 5°C, at which it has a polymorphic transformation into a high-temperature (HT) hexagonal polymorphic modification (Sp. gr. P63/mmc), which is stable until melted at 840°C based on DSC. The thermal expansion of both modifications is sharply anisotropic, and in the case of the HT phase the parameter a has a U-shape dependence with a minimum at T = 620°C. The volumetric expansion of the αV HT phase is greater than that for the LT phase by factors of 2–2.5 on average.

Vulcanian explosions are hazardous and are often spontaneous and direct observations are therefore challenging. Ebeko is an active volcano on Paramushir Island, northern Kuril Islands, showing characteristic Vulcanian-type activity. In 2019, we started a comprehensive survey using a combination of geophysical field station records and repeated unoccupied aircraft system (UAS) surveys to describe the geomorphological features of the edifice and its evolution during ongoing activity. Seismic data revealed the activity of the volcano and were complemented by monitoring cameras, showing a mean explosion interval of 34 min. Digital terrain data generated from UAS quadcopter photographs allowed for the identification of the dimensions of the craters, a structural architecture and the tephra deposition at cm-scale resolution. The UAS was equipped with a thermal camera, which in combination with the terrain data, allowed it to identify fumaroles, volcano-tectonic structures and vents and generate a catalog of 282 thermal spots. The data provide details on a nested crater complex, aligned NNE-SSW, erupting on the northern rim of the former North Crater. Our catalog of thermal spots also follows a similar alignment on the edifice-scale and is also affected by topography on a local scale. New analysis are included in this presentation as well as a long term change analysis based on remote sensing data.

Ebeko is one of the most active volcanoes of the Kurile island arc, producing frequent mild Vulcanian explosions with eruption clouds up to 5 km high. The volcano poses a serious threat to the Severo-Kurilsk town with a population of around 2500 inhabitants, located at a distance of only 7 km on a fan of the volcano’s laharic deposits. Here, we report an overview of the activity of the volcano in the 20th–21st centuries and the results of our geological and petrological investigations of the ongoing Vulcanian eruption that started in 2016. We have found that eruptions of Ebeko span a range of mechanisms from purely magmatic to phreatic/hydrothermal. Three of its historical eruptions (the 1934–1935, 1987–1991, and the 2016–ongoing) involved fresh magma, while during the others (1967–1971, 2009–2011) fresh magma was not erupted. Juvenile material of the ongoing eruption represents highly crystalline and highly viscous (more than 108 pa s) low-silica (56–58 wt% SiO2) andesite. Historical data and our observations of the ongoing eruption allowed us to suggest a functional model of the volcano where Vulcanian explosions are caused by shallow intrusions of small diapir-like batches of strongly crystallized and highly viscous andesitic magma ascending into water-saturated, hydrothermally altered rocks composing the volcano summit. We suggest that the diapir’s ascent is governed by their positive buoyancy. Some of the diapirs reach and breach the ground surface producing magmatic eruptions of Ebeko, while the others are stuck at the shallow subsurface level and feed intensive hydrothermal activity as well as phreatic eruptions of the volcano. Positive buoyancy of the diapirs is too weak to allow them to extrude high above the ground surface to form lava domes.