This study investigated the evolution of the magma and hydrothermal system of the Azuma-Jododaira volcano, focusing on the geology and ash petrology of the tephra layers. Eight tephra layers were identified in the Jododaira-Iwodaira area (bottom to top): L1–1, L1–2, L2, L3, L4, L5, L6, and L7. Layers L1–1 to L1–2 and L3 to L4 are correlated with the 1331 CE Az-OA and 1771 CE JP7 units, respectively

Topographic changes or ground surface deformation provide critical information regarding the fluid ascent paths that form in permeable fracture zones. This study combines surface displacement data using the small baseline subset-interferometric synthetic aperture radar (SBAS-InSAR) technique, lineament density, topographic elevation, and water type in geothermally active areas to detect highly permeable

More than half of explosive volcanic eruptions contain multiple eruption phases with eruption dynamics (i.e., style, intensity, magnitude) varying with eruption progression. While probabilistic eruption forecast models constitute a useful tool for decision making during volcanic crises, the probabilistic forecast of likelihood, style and magnitude of potentially upcoming phase(s) within a multi-phase

The 2014–2015 Holuhraun eruption extruded >1 km3 of lava in a barren region of the Icelandic highlands. Due to its large volume and the abundance of data for this eruption, Holuhraun is an ideal site to investigate fissure-fed eruption products for comparison with other large lava flows-fields on Earth and other planetary bodies. To characterize lava morphologies associated with this event, we used

We report the temporal evolution of helium isotopes emission and thermal energy release in the period 2007–2018 at the summit crater of Pico do Fogo volcano, Cape Verde. 3He/4He ratio measured in a fumarolic discharge, ranged from 6.69 to 8.63 RA, being the maximum mantle-derived composition measured in November 2013, one year before the eruption onset in 23 November 2014, and confirm the beginning

The Hofsjökull volcanic system is located at the northern border of the Hreppar microplate on the Mid-Atlantic plate boundary in Iceland, between the more active Western and Eastern volcanic zones. In this study, fractures, and faults within the fissure swarms of the volcanic system were mapped and the throw and orientation of faults measured. This was done using both aerial photographs and ArcticDEM

Between August 2014 and February 2015, a caldera collapse process in Bárðarbunga volcano accompanied a fissure eruption at the Holuhraun lava field after magma had propagated laterally 45 km from the Bárðarbunga magma chamber to the lava field. The Icelandic Meteorological Office (IMO) reported around 30,000 earthquakes at the caldera, including more than 70 earthquakes with moment magnitude MW ≥ 5

The Quaternary Coso Volcanic field (CVF) is a compositionally bimodal volcanic field located within a releasing bend along the eastern range-front Sierra Nevada fault zone in California's southern Owens Valley. The erupted products of CVF silicic magmatism since ~1 Ma comprise 38 high-silica rhyolite domes, with the volumetric majority (~99%) of rhyolite emplaced within the past ~300 ka. The CVF hosts

In the East African Rift System (EARS) tectonic inheritance rules the location, the shape and the development of rift segments. Such lithospheric/crustal-scale inherited structures may be exploited by magma favouring its ascent to shallow crustal level and, possibly, to the surface producing volcanism. In the eastern branch of the EARS in southeast Kenya, the Pleistocene Chyulu Hills volcanic field

This work presents the first record of boron-rich aqueous solutions in barite-, anhydrite-, and sassolite-hosted fluid inclusions found in the fumarolic deposits of the Guallatiri volcano, an active and quiescently degassing volcano located in northern Chile. These findings offer a unique opportunity to investigate the mineral-forming and depositional processes in fumarolic environments. Chemical and

Detecting transitions between different eruption styles through real-time monitoring can mitigate the risk posed by volcanic hazards. During periods of eruptive activity, changes in ash characteristics can reflect changes in magma behavior in the conduit. However, conventional methods for characterizing ash involve manual field processes followed by laboratory observations, which leads to a potential

In this paper we simulate the economic impacts and land use changes associated with a volcanic eruption scenario for the Auckland region of New Zealand for a period of 20 years following the eruption. The simulation demonstrates the capability to model not only the direct physical impacts associated with infrastructure and land use destruction and disruption, but also population and business evacuation

To quantify the size of tephra, two practical challenges must be addressed: the wide range of particle sizes (10−8 - 101 m) and the diversity of particle shape, density and optical properties. Here we use dynamic image analysis (DIA) to simultaneously characterise the size and shape of tephra samples from Mount Mazama, Krafla, Mount St. Helens and Campi Flegrei. The Camsizer X2 instrument used in this

The southern portion of the Mesa Central (MC) physiographic province is covered by numerous Oligocene to Miocene volcanic successions that are part of the Sierra Madre Occidental silicic large igneous province. The MC merges with the Sierra Madre Occidental and the southern Basin and Range extensional province. The voluminous Villa Garcia-Loreto Volcanic Complex (VGLVC) is located in the southern portion

In recent literature thermo-poro-elastic (TPE) inclusions are proposed to contribute to deformation and stress in volcanic and hydrothermal areas. With respect to previous works, the present study implements the modeling improvements requested for a more realistic description of a TPE source and the embedding medium. Firstly we propose a numerical method to represent inclusions with an arbitrary geometry

The magnitude and intensity of the 60 CE Cretaio Tephra, the largest historical explosive eruption at Ischia caldera (Italy), was studied integrating field data and numerical modelling in order to reconstruct the dispersal of the fallout related to the climax phase of the eruption and characterize its physical parameters. A field survey of the main fall unit (EUC) of Cretaio Tephra and its sampling

We present integrated structural, petrological, mineralogical and geochemical investigations conducted on an exhumed hydrothermal system identified in Terre-de-Haut Island (Guadeloupe archipelago). This work demonstrates, for the first time, the occurrence of ductile shear zones, marked by the development of spaced schistosity planes generated by pressure-solution processes. We unravel first that the

We use ground and space geodetic data to study surface deformation at Kīlauea Volcano from January to September 2015. This period includes an episode of heightened activity in April and May 2015 that culminated in a magmatic intrusion beneath the volcano's summit. The data set consists of Global Navigation Satellite System (GNSS), tilt, visual and seismic time series along with 25 descending and 15

In this paper we explore the efficiency of various machine learning techniques to determine the volcano source, the eruptive formation and the eruption period of volcanic rocks when their chemical contents are known. With this aim, we assembled a data set of 9800 volcanic rocks from the open-access literature. The rocks belong to eruptive formations from Somma-Vesuvius, Campi Flegrei, Ischia and Procida

Between 1992 and the mid 2010s, strong uplift has been observed centred on Uturuncu volcano in Bolivia. More recently it was shown that a smaller-amplitude moat of subsidence surrounds the uplift. We propose that this “sombrero” pattern can be the signature of elastic-plate deformation due to a buoyant fluid stored beneath it. We take the base of the “plate” to be the brittle ductile transition which

Recent eruptions of Kīlauea volcano, on the Island of Hawai'i, represent an ideal test location for studying volcanic plumes, due to its remote location and minimal anthropogenic pollution. Within this work we exploit the over 20-year data record from NASA EOS satellites to investigate the degree to which space-borne observations can detect shifts in known eruption dynamics at Kīlauea. Through the

The Socompa stratovolcano is located in the Andean Central Volcanic Zone, where active volcanism turns it into an area of interest for geothermal resources. In the surroundings of the volcano, the Socompa Geothermal Prospect was carried out looking for thermal manifestations related to an active geothermal system. The results of these preliminary studies are not conclusive. Here we present a geoelectrical

Fluids supplied by stored magma at depth are causal factors of volcanic unrest, as they can cause pressurization/heating of hydrothermal systems. However, evidence for links between hydrothermal pressurization, CO2 emission and volcano seismicity have remained elusive. Here, we use recent (2010−2020) observations at Campi Flegrei caldera (CFc) to show hydrothermal pressure, gas emission and seismicity

A large number of thermal springs are widely distributed along the deep suture zones and faults in the north section of the Sanjiang Orogenic belt in southeast Tibetan Plateau, connecting the two high-temperature hydrothermal areas in southern Tibet and western Sichuan. Whether the genesis of all geothermal water in the north section of the Sanjiang Orogenic belt is consistent is still an unanswered

The Tilocálar volcanic complex comprises four monogenetic volcanoes located at the southeastern edge of the Salar de Atacama Basin, northern Chile. These monogenetic volcanic centers are the Tilocálar Norte lava, the El Maní dome, the Tilocálar Sur small–lava shield, and the Tilocálar Sur maar, respectively, and were formed between 460 ± 50 ka to < 1 Ma ago along the north–south-striking Tilomonte

We provide evidence that noble gasses (NGs) trapped in Pele's hairs and tears can be used as a tool to monitor the degassing behaviour of persistently active volcanic systems. We investigated 4He, 36Ar, 40Ar abundances and 4He/40Ar* and 40Ar/36Ar isotopic ratios in samples collected in March 2015 and March 2016 from Masaya volcano (Nicaragua). The resurgence of a lava lake in December 2015 provided

The Caviahue-Copahue Volcanic Complex (CCVC) hosts one of Argentina's most important geothermal systems. To provide new insights into origin, circulation, and residence time of fluids, the chemical and isotopic composition (3He/4He, δ2H-δ18O in H2O; δ13C-δ18O in CO2; 87Sr/86Sr) of thermal waters was measured together with the 3H and 14C activities. Water samples were collected from hot springs (LM

Understanding the petrogenesis of silicic magmas is critical for understanding the volcanic hazards they pose, their geothermal energy potential, and the creation of continental crust. In this study we explore the origin of rhyolitic magmas in basaltic crust at the Krafla Central Volcano in Iceland. We present laser fluorination oxygen isotope analyses of plagioclase, pyroxene, and groundmass from

More than 70 years observation of the SO42−/Cl− molar ratios of water from the Obuki hot spring in the vicinity of Mt. Akita-Yakeyama volcano indicated that the ratio started increasing rapidly from 1973, peaked in 1980 (SO42−/Cl− = 0.34), remained at high values for about 18 years, then gradually decreased and returned to a normal baseline value (0.14) in 1991. The volcano erupted near the summit

Numerical models of geothermal systems have achieved considerable progress when dealing with fundamental transport processes. Site-specific geothermal models however, often face the lack of sufficient field data, which leads to under constrained models. Recent field studies in the Las Tres Virgenes volcanic complex (TVVC) provide us with a sound framework to build a numerical model for the magmatic

Yellowstone Lake hydrothermal vent systems have been studied using ROV assets to better understand the chemical and mineralogical evolution of the sublacustrine sediments through which the hot spring fluids discharge to the lake floor. Here we focus on the deposits/alteration and coexisting vent fluid chemistry associated with the Deep Hole on the lake floor, east of Stevenson Island. Remote in its

Steamboat Geyser in Norris Geyser Basin in the northwestern part of Yellowstone National Park is the highest erupting active geyser in the world with jets of fluids observed to be as high as 115 m. Steamboat eruptions increased from 11 between 2000 and 2017 to 131 between 19 April 2018 and 21 February 2021. Recurrence intervals are now irregular, averaging 8 ± 4 (1σ) days between each event. To examine

In volcano gravimetry, when analyzing residual spatiotemporal (time-lapse) gravity changes, the accurate deformation-induced topographic effect (DITE) should be used to account for the gravitational effect of surface deformation. Numerical realization of DITE requires the deformation field available in grid form. We compute the accurate DITE correction for gravity changes observed at the Laguna del

We present the results of analogue laboratory experiments on pyroclastic fountain collapse. Mixtures of air and glass beads ranging in size around 75 ± 15 μm, with Stokes number of ~10−3−101 and representative of 0.1–1 mm sized particles in nature, were released from a hopper at heights of 0.45–2.95 m above the base of a horizontal channel. Free fall caused continuous dilation of the granular material

Using Sentinel-1A/B SAR data, Harvey (2021) produced an InSAR timeseries over White Island, New Zealand. The paper documents the apparent deformation through 2019, with particular focus on the mechanisms surrounding the fatal eruption on December 9 of that year. Based on the analysis, the author suggests that a sudden increase in the Line of Sight (LOS) range occurred two weeks prior to the eruption

In this study we demonstrate how very-long period (VLP) volcanic seismic signals can be processed in order to obtain essential and detailed information about the seismo-volcanic source process. As an example we use the VLP signal observed on 23 March 2012 during an outgassing event at Soufrière Hills volcano, Montserrat, acquired by instruments with different natural periods. The aim of this study

We use new estimates of the total content and speciation of volatiles released during the ascent and eruption of lunar mare basalt magma to model the generation and behavior of gas bubbles, the disruption of magma at shallow depth by bubble expansion, and the acceleration and dispersal of the resulting pyroclasts. Lunar eruptions in near-vacuum differ significantly from those on bodies with an atmosphere:

Degassing volcanic systems, expressed by fumaroles, thermal anomalies, and hydrothermal alteration and deposition at the surface provide insights into the underlying structural architecture and the magmatic system. While the fumarole sites are easily identified and investigated, areas of diffuse degassing and associated hydrothermal alteration are barely explored. Here we investigate high-resolution

A study of anisotropic characteristics based on shear wave splitting (SWS) parameters (fast shear wave polarization and delay time) was carried out on 121 microearthquakes recorded by seismic arrays installed in Los Humeros Geothermal Field, Puebla, Mexico from 2011 to 2016. This analysis determined how both parameters seem to have been influenced by the geothermal field operation and by the spatial

We present a textural investigation of compositionally homogeneous alkaline tube pumices from the plinian fallouts of the Agnano Monte Spina eruption (ca. 4.1 ka), Campi Flegrei, Italy. The pumice clasts present strong textural complexity from hand specimen to microscopic scale of inspection. The clasts are characterized by large vesicle tubes that extend up to several millimetres along the clast main

The accurate labeling of the volcanic earthquake signals is a crucial task in order to estimate the increase in volcanic activity (among other parameters), which contributes to determine a state of volcanic unrest (as a possible precursor of an eruption). Several automatic classification approaches have been proposed in different computer science areas in order to complement the exhaustive human task

Batu Tara is an active but poorly studied volcano located in the Lesser Sunda Archipelago (Indonesia). Its last known long-lasting eruptive phase, dating 2006–2015, was characterised by frequent short-lived explosions, similar in style and magnitude to those of the well monitored Stromboli volcano (Italy). On September 2014, we collected high-frequency multi-parametric measurements of the ongoing explosive

This study presents the first high resolution geophysical survey conducted in The El Tatio geothermal field, northern of Chile, focused on the detection of shallow subsurface structures and identification of ascending fluid pathways. TEM data was collected along 5 profiles crossing the two main geothermal basins (Upper and Middle Basin) to obtain an electrical resistivity model up to 200 m depth. The

This paper demonstrates the advantages of three-dimensional (3D) analysis and visualization of weather radar data for studies on the inner structure of eruption columns and their 3D ash-fall distributions. The 3D data were collected using an operational X-band polarimetric radar located ~11 km from the Showa vent of Sakurajima, Japan. Three eruption cases were chosen for the analysis to study the effect

The post-collisional Syunik and Vardenis volcanic highlands, located in the southern Lesser Caucasus mountains (part of the Arabia-Eurasia collision zone) are host to over 200 monogenetic volcanoes, as well as 2 large Quaternary polygenetic volcanoes in the Syunik highland. The latter are overlain by lavas from the monogenetic volcanoes, suggesting there was a transition in the style of volcanic activity

The dangerous juxtaposition of human populations and active volcanic arcs worldwide makes elucidating the history of explosive eruptions of these arcs a crucial endeavor. The well-preserved Deschutes Formation, which forms part of the Deschutes Basin of central Oregon, USA, contains a distal record of a period of unusually frequent explosive eruptions between 5.45 and 6.25 Ma, which is atypical of

Several kilometers of rapid uplift in the past 2–3 million years in the Greater Caucasus in Russia has produced world-class exposures of Pliocene-Pleistocene age granites and ignimbrites at the Tyrnyauz and Chegem volcanic centers just to the east of Europe's highest mountain and active volcano, Mount Elbrus. This represents one of the world's best-preserved examples of silicic magmatism in a continental

Both chemical and isotopic compositions of volcanic plumes are highly useful in evaluating the present status of active volcanoes. Monitoring their temporal changes can facilitate the forecasts of volcanic activity as well. In the present study, we developed a drone-borne automatic sampler for volcanic plumes in which an output signal from a sulfur dioxide (SO2) sensor triggered a pump to collect samples

The Quaternary Villamaría-Termales Monogenetic Volcanic Field (VTMVF) is one of the monogenetic fields located within the subduction related, volcanic chain in the northern Colombian Andes. The dominantly andesitic composition of the products from this field provides an opportunity to study the crystallisation history of monogenetic volcanic products, associated with long term crustal stagnation before

Potrerillo I, Potrerillo II, and San Juanito volcanoes are part of the 28 Late Quaternary monogenetic eruptive vents concentrated along a ~2-km-wide and ~30-km-long stripe in the vicinity of Ceboruco stratovolcano (western Mexican Volcanic Belt). The studied volcanoes are closely spaced and located within a ~12 km2 sub-drainage basin, northwest of Ceboruco's edifice. Eruptive dynamics were inferred

Isotopic (D, 3H, 18O, and 34S) and chemical studies on the hyper-acidic hot spring waters (Obuki; pH 1.1), other hot spring waters, and fumarolic gases taken in 1990–1992 at Tamagawa Hot Spring, Akita, Japan were undertaken to investigate the source and behavior of sulfur compounds. The Obuki hot spring water discharges after mixing of magmatic gas with meteoric water and underground vapor–liquid separation

Cleveland and Tana are remote volcanoes located in the central Aleutian volcanic arc on the eastern end of the Islands of Four Mountains (IFM). The persistently active Mount Cleveland volcano, on the western side of Chuginadak Island, is surrounded by several closely spaced Quaternary volcanic centers including Carlisle, Herbert, Kagamil, Tana, and Uliaga, and numerous small satellite vents on Chiginadak

Sangay is one of the most active volcanoes in the world. Its eruptions were first recorded by Spanish priests in 1628, and since 2010 it has displayed VEI 1–2 level eruptive activity about every two years. Its most recent eruptive phase began on May 7, 2019, and has continued until the present. While most eruptive products do not impact inhabited areas, Sangay's associated Pleistocene-age avalanche

Resurgence uplift is the rising of the caldera floor, mainly due to pressure or volume changes in the magma reservoir. Identifying resurgence structures and understanding their relationship to the magmatic reservoir is challenging. We investigate the resurgence structures of the Neapolitan Yellow Tuff caldera (Italy) by integrating bathymetric data, high-resolution seismic profiles and Differential

Motuoapa Peninsula, located in the southeast of the Taupo Volcanic Centre, New Zealand, is dominated by a silicic pyroclastic cone and overlaying lavas. The pyroclastic succession has not been recognised and studied before, and its thickness and sedimentological characteristics indicate completely different eruption mechanisms than proposed for the other pyroclastic successions within the central Taupo