Eruptive Phase Research Articles

Monitoring the Thermal Activity of Kamchatkan Volcanoes during 2015–2022 Using Remote Sensing

The powerful explosive eruptions with large volumes of volcanic ash pose a great danger to the population and jet aircraft. Global experience in monitoring volcanoes and observing changes in the parameters of their thermal anomalies is successfully used to analyze the activity of volcanoes and predict their danger to the population. The Kamchatka Peninsula in Russia, with its 30 active volcanoes, is one of the most volcanically active regions in the world. The article considers the thermal activity in 2015–2022 of the Klyuchevskoy, Sheveluch, Bezymianny, and Karymsky volcanoes, whose rock composition varies from basaltic andesite to dacite. This study is based on the analysis of the Value of Temperature Difference between the thermal Anomaly and the Background (the VTDAB), obtained by manual processing of the AVHRR, MODIS, VIIRS, and MSU-MR satellite data in the VolSatView information system. Based on the VTDAB data, the following “background activity of the volcanoes” was determined: 20 °C for Sheveluch and Bezymianny, 12 °C for Klyuchevskoy, and 13–15 °C for Karymsky. This study showed that the highest temperature of the thermal anomaly corresponds to the juvenile magmatic material that arrived on the earth’s surface. The highest VTDAB is different for each volcano; it depends on the composition of the eruptive products produced by the volcano and on the character of an eruption. A joint analysis of the dynamics of the eruption of each volcano and changes in its thermal activity made it possible to determine the range of the VTDAB for different phases of a volcanic eruption.

Magma plumbing architectures and timescales of magmatic processes during historical magmatism on the Reykjanes Peninsula, Iceland

In the past 4000 years, three rifting episodes have occurred on the Reykjanes Peninsula (RP, SW Iceland) at time intervals of about 800-1000 years, with the activation of four of the five volcanic systems on the peninsula: Reykjanes, Svartsengi, Krýsuvík and Brennisteinsfjöll. In 2021 AD, 2022 AD and 2023 AD, three eruptions occurred in the Fagradalsfjall volcanic system, the only volcanic system that remained inactive during these past rifting episodes. Considering the eruptive history of the peninsula, this could mark the onset of a new eruptive episode. Although extensive petrochemical datasets have emerged from past rifting episodes, little is known about magma plumbing configuration and timescales of pre-eruptive magmatic processes. In this work, we focus on 16 basaltic lava units erupted across RP during a well-established rifting episode: the 800-1240 AD Fires. We analysed major and minor element contents of glasses, mineral phases and melt inclusions, and we reconstruct plumbing system architecture and constrain mixing-to-eruption timescales, with the goal of assessing likely eruption scenarios of a possible future eruptive episode. Mineral-melt equilibria suggests that most of crystal cores are antecrysts that did not crystallize from the magmas that carried them to the surface, but instead were scavenged from disaggregating mush layers genetically related to the erupted magmas. Magmas erupted in the easternmost part of the RP reveal larger contributions from geochemically enriched mantle-derived melts. However, MIs that record various extents of mixing of geochemically enriched and depleted components throughout the entire peninsula appear devoid of any spatial control of the underlying mantle. Independent clinopyroxene-melt and melt-based barometry, after correction for microlite crystallization, show consistent results and suggest that magmas from the western part of the peninsula were extracted from reservoirs located at about 7-10 km depth. In contrast, and similar to observations from recent eruptions at Fagradalsfjall, the easternmost system, Brennisteinsfjöll, was fed from deeper crustal reservoirs, at about 14-21 km depth. Fe-Mg diffusion chronometry applied to olivine rims suggests short mixing-to-eruption timescales on the order of days to weeks and likely faster ascent rates of magmas underneath Brennisteinsfjöll. Compared to 2021 AD Fagradalsfjall, mixing-to-eruption timescales were considerably shorter during the 800-1240 AD Fires. With inferred eruption durations on the order of months, the short olivine rim diffusion records are consistent with several discrete eruptive phases, which eventually assembled the individual magmatic units. In the light of possible future eruptive episodes on the RP, our work suggests that magmas are likely to accumulate at persistent depths across the RP, with key implication for interpreting pre-eruptive signals and eruption mitigation.

The role of phreatomagmatism in the formation of complex monogenetic volcanic systems in a low-lying coastal plain

Monogenetic volcanoes are characterised worldwide by a single eruptive phase that is short-lived, with small eruptive volumes that produce a wide range and complexity of landforms. Investigating the evolution in eruptive styles through the active history of a volcano is key to understanding the role of phreatomagmatism in the formation of these complex monogenetic systems. The classification of the complexity of a monogenetic volcanic centre is of great significance to understanding both past volcanoes and the hazards of future volcanoes. Complexity can be defined by the number of volcanic structures created, the presence of multiple types of eruptions, and the number of conduits involved. In this paper we reconstruct the volcanic history of the Waitomokia Volcanic Complex, located in the southern lowlands of the active monogenetic Auckland Volcanic Field (AVF), New Zealand. Activity began with deposition of an initial tuff ring, followed by vent migration and establishment of a maar with a surrounding tuff ring. Four smaller tuff rings developed on the north and northeastern rim of the maar. This was followed by the noteworthy deposition of complex intercalated transitional deposits from at least two tuff rings and magmatic deposits from a scoria cone. Three scoria cones were then built within the maar, followed by minor effusion of short lava flows. Waitomokia highlights the prospect of having a complex system with ten or more landforms being created in different areas active at the same time, with associated eruptive styles and mechanisms. The possibility of a complex eruption, where several styles may occur simultaneously from distinct vents, should be considered in hazard assessment and crisis management plans.

One decade of b-value variations from volcano-tectonic seismicity as an early indicator of episodes of crisis in a volcano: the case of Copahue, Southern Andes

Volcanoes can enter in episodes of unrest, which might end later in an eruption, with little warning. They are normally produced due to the inner dynamics of the volcano, but can also be triggered by external earthquakes. To detect these periods early, it becomes crucial to understand the dynamics of the different structures (such as fault systems) of the volcano, as they can act as magma pathways and can also generate instabilities on it. In this article we study the seismicity of Copahue (central-south Chile), which sits atop a complex system of faults, and was importantly affected by the 2010 Mw 8.8 Maule earthquake. We focused ourselves in the temporal variations of the b-value of the Gutenberg-Richter law during the 2012–2022 period. During this timeframe the volcano had a series of crises, which led to seven eruptive phases. Our results show that the system does exhibit signs of a future unrest phase weeks to months before there is a change on its alert level, and they are mostly linked to the activity of a N-S fault zone, located not beneath the main crater of Copahue, but around 10 km to the East. Most of the crises start after drops in the b-value of this structure, with sudden variations in b-value being also noticeable as a response to the 2015 Mw 8.3 Illapel earthquake. Our results show a correlation between instances of fluid injection and release in the relevant structures of an active volcano with the variations of the b-value. This allow us to use the temporal variations of the b-value as a tool to anticipate the inner dynamics of the system, particularly when there is a strong structural control on it, such as in the case of Copahue. We also found out that the influence of the 2010 Mw 8.8 Maule earthquake was long-lived, affecting mostly the structures that later destabilized the volcano for the most part of a decade, therefore enhancing magma injection into the whole system. This seems to have changed since 2021, which might indicate a waning in the influence of the megathrust earthquake in Copahue volcano.

Epithelial-specific deletion of FAM20A leads to short root defects

Short Root Defects defined by a reduced ratio of root to crown, may culminate in root resorption and subsequent tooth loss, in spite of the absence of apparent symptoms. Such defects present considerable impediments to orthodontic treatment and restoration. Recent identification of Fam20a, an emergent pseudokinase, has been associated with enamel development and tooth eruption, yet its definitive role in root formation and eruption remains ambiguous. In this research, we initially ascertained that the targeted knockout of Fam20a within the epithelium led to truncated tooth roots, irregular breaks in the epithelial root sheath initiation of the WNT signaling pathway, and decreased expression of the cell polarity-related transcription factor Cdc42 in murine models. This was concomitant with the participation of the associated epithelial root sheath developmental pathways BMP2, Gli1, and Nfic. Furthermore, we observed that Fam20a predominantly affects the intraosseous eruption phase of tooth emergence. During this phase, the osteoclast peak around the mandibular first molar in cKO mice is delayed, leading to a slower formation of the eruption pathway, ultimately resulting in delayed tooth eruption in mice. The findings of this study enrich the extant knowledge regarding the role of Fam20a, suggesting its potential regulatory function in tooth root development through the WNT/β-catenin/Cdc42 pathway.

Temporal and spatial evolution of the 2021 eruption in the Tajogaite volcano (Cumbre Vieja rift zone, La Palma, Canary Islands) from geophysical and geodetic parameter analyses

The eruption of the Tajogaite volcano in 2021, in the Cumbre Vieja rift zone (La Palma, Canary Islands), is the most recent but also the most damaging and longest-lasting eruption on the island since historical records began. We analyzed geophysical parameters (seismicity, surface deformation, thermal anomalies, and volcanic activity) with the aim of reconstructing the temporal development of the magma plumbing system. The seismic sequence (> 9000 events, mbLg ≤ 5.0) can be grouped into nine distinct phases, which correspond to well-separated spatial clusters and distinct earthquake regimes. A strong premonitory thermal anomaly was calculated on July 2021 in the South of La Palma. The source of the magma was within the upper mantle (40–20 km depth). A second magma budget (< 15 km depth) indicated a short-term stagnation of alkaline magma within the lower crust, near the Moho. The outline of these earthquakes delineates the magma pathway. Just before and immediately after the eruption (phases 2 and 3), the high-frequency seismicity in the mantle disappeared completely, reappearing ten days after the eruption started. The pattern of deformation began before the eruption with a breakpoint around September 11, after which, deformation accelerated sharply, followed by stabilization in phase 3 and a decrease in the following phases. The level of deformation suggested that a shallow magma intrusion was established. Based on the historical eruptive pattern, it is possible to infer two possible hazard-forecast scenarios: (a) the volcano could enter a prolonged phase of tranquility for more than one century or, (b) a new eruption could occur between ca. 2045 and 2065, with a slightly shorter duration than this recent one. Therefore, if the more pessimistic scenario is assumed, appropriate territorial planning is required.

In-situ monitoring of 3He/4He in summit gases of Kilauea Volcano (Hawaii) prior to the 2020 eruption

We present He isotope (3He/4He) data from a fumarole and near-ground gases measured in-situ at the Sulfur Banks solfatara field at the summit of Kilauea Volcano, Hawaii. We used a field-deployable mass-spectrometer-based system: the Helium Isotope Monitor (HIM) previously described in McMurtry et al. (2019a, b). The in-situ instrument was deployed using solar power for the first time and results were ground-truthed against data determined using conventional gas analytical and noble gas mass spectrometry techniques. The HIM instrumentation, associated Vent Gas Purification System (VGPS), and related sampling equipment and strategy are described. Cloudy and rainy weather conditions hampered the deployment, which was reorganized to reduce power loads and resulted in less sampling than planned. Nevertheless, we obtained daily sampling of the volcanic vent gas. Results from the Old Well fumarole indicate a ~ 2 RA increase in 3He/4He on the day of the December 20th, 2020 eruption of nearby Halema‘uma‘u Crater, reaching 17.0 RA using the in-situ instrument and 16.0 ± 0.67 RA using conventional techniques. This finding suggests that a new 3He-enriched magma source is driving the current, ongoing eruption phase of Kilauea and, if so, confirms that the deep summit caldera fault system that hosts the Sulfur Banks field is connected to the Halema‘uma‘u Crater magmatic system. Overall, these findings illustrate how time-series helium isotope data, which are well established by ongoing discrete monitoring at low temporal resolution, can help forecast forthcoming eruptive events that may not be foreseen by other volcanic monitoring methods.

Electron microprobe dating of monazites from rhyolites of the Veľká Stožka Massif (Muráň nappe, Western Carpathians) – implications for the Permian volcanic evolution in Internal Western Carpathians

New results of field research, as well as petrographical and geochronological studies are presented in the form of a geological map, tectonostratigraphic scheme and new magmatic age data of monazite crystallization from the rhyolite body located on SW slopes of the Veľká Stožka Massif, Dudlavka Valley (Muráň Plateau). The rhyolite bodies in the Veľká Stožka area are tectonically incorporated into the Lower Triassic formations at the base of the Muráň nappe. The electron microprobe dating of monazites yields magmatic / volcanic age 281 ± 4.5 Ma (Artinskian – Kungurian), which complements geochronological data from the same rhyolite body below the Veľká Stožka Massif, as well as other rhyolite bodies from Telgárt, Poniky and Tisovec, which, originally erupted in a Permian volcanically active fault zone (VAFZ) geodynamical setting. The comparison of geochronological data 281 ± 4.5 Ma and 269.5 ± 1.8 Ma from the studied locality suggest a geodynamic evolution, where not only one, but several separate volcanic eruption phases acted in the original domain of rhyolitic volcanism. The geochronological correlation of the rhyolite bodies in the Upper Hron Valley, active in time span 281–263 Ma, allowed to identify a volcanic hiatus between 280–271 Ma. Such eruptional pause correlates very well with other volcanic provinces such as Harnobis volcanogenic horizon of the North Veporic realm, the Petrova hora and Novoveská Huta Fm. of the Northern Gemericum, which erupted during hiatus of VAFZ and their activities have ended in during recovering rhyolite eruptions in VAFZ. Reactivation of rhyolitic volcanic activity in VAFZ 271–263 Ma is a result of paleostress reorganisation in Pangea lithosphere. The revealed paleovolcanic relationships highlight interconnection of paleotectonic and paleovolcanic events in the known paleotectonic units of Internal Western Carpathians during Permian.

The Coastal Areas of the Bay of Naples: The Sedimentary Dynamics and Geological Evolution of the Naples Canyons

The sedimentary dynamics and geological evolution of the Naples canyons during the Late Quaternary have been studied based on sedimentological and seismo-stratigraphic data. Several factors, including the sedimentary environments, tectonic setting, and volcanic eruptions, have controlled the geological evolution of the coastal and marine areas of the Bay of Naples. The main data and methods include the sedimentological data analysis, the seismo-stratigraphic techniques applied in the geological interpretation of seismic profiles, and the integrated analysis of core data that were previously published. The formation of the Dohrn canyon is controlled by fluvial processes, active in correspondence with the palaeo-Schiazzano River system and by the main eruptive events involving the submarine portion of Naples Bay, including the Campanian Ignimbrite (CI; 39 ky B.P.) and the Neapolitan Yellow Tuff (NYT; 15 ky B.P.). The formation of the Magnaghi canyon is controlled by erosional processes on the continental slope of Procida Island, which was active during the last eruptive phases of the island (Solchiaro Formation; 18 ky B.P.), triggering high rates of volcaniclastic supply.

Multi-method constraints on the age and timescale of silicic small-volume eruptions of Puketerata Volcanic Complex, Taupō Volcanic Zone, New Zealand

Accurate dating of young eruptions from explosive volcanoes is essential for forecasting future eruptions and for defining the hazardscape of volcanic fields. However, precise dating of Quaternary eruptions is often challenging due to limited number of applicable dating methods or lack of datable eruptive phases. Moreover, small volume eruptions (e.g., monogenetic type), despite their significance on regional scale, have traditionally deserved less attention than their large volume counterparts. Puketerata is a maar-lava dome complex in the central Taupō Volcanic Zone (New Zealand), encompassing mafic and silicic phreatomagmatic eruptions with well-preserved pyroclastic deposits sourced from closely spaced vents. Its most recent activity is estimated to ca. 16 ka based on medial and distal stratigraphic surveys. Here, we carried out two independent age determinations and an additional paleomagnetic analysis on the volcanic succession of the Puketerata maar-lava dome complex with an aim to unravel the timing of volcanic activity. Combined U-Th disequilibrium and (U-Th)/He dating of zircon from two lava domes yielded eruption ages of 11.3 ± 2.6 ka and 11.3 ± 1.7 ka, which are concordant with the radiocarbon ages of 11.3–11.7 ka obtained on charcoal from the base of the pyroclastic sequence. Paleomagnetic data on the lavas from the two lava domes suggest at least ~ 100 years difference between their emplacements. Our geochronological results and new stratigraphic observations suggest that the volcanic/magmatic history of the Puketerata is complex with multiple eruptions within a small, confined area, where the most recent eruptions occurred only at ca. 11.5 ka, which is significantly younger than previously thought. This provides an additional datum for volcanic hazards assessment and stratigraphic correlations in New Zealand.Graphical

Eruption dynamics and plumbing system of Shikabe Geyser in southern Hokkaido, Japan, revealed by field observation inside and outside the conduit

The development of observation and data analysis techniques has advanced the understanding of the plumbing systems that contribute to the eruption dynamics of geysers. However, the interrelations between the plumbing system, dynamic and thermal processes inside the conduit, and surface phenomena remain unclear. We recorded video images, pressure, and temperature inside and outside the conduit of the Shikabe Geyser, a geysering well in southern Hokkaido, Japan. Video observations revealed that numerous bubbles are generated in the deep part of the conduit immediately after the eruption begins. However, the water temperature at depth is lower than the boiling point throughout the eruption cycle. The directly measured volume of discharged water indicate that the water supply rate during the eruption phase is significantly higher than that during the recharge phase. At the Shikabe Geyser, there may be void spaces composed of cracks and porous media around the deep part of the conduit, and high-temperature water containing dissolved CO2 gas is likely supplied from the reservoir. Dissolved CO2 plays a critical role in decreasing the boiling point of water. When an eruption occurs, steam with CO2 gas nucleation and expansion owing to decompression drives the vigorous discharge of water at the vent. Simultaneously, bubbles are generated inside the cracks in the aquifer owing to decompression, which may contribute to oversupply during the eruption.

The Relation Between Decadal Droughts and Eruptions of Steamboat Geyser in Yellowstone National Park, USA

AbstractIn the past century, most eruptions of Steamboat Geyser in Yellowstone National Park's Norris Geyser Basin were mainly clustered in three episodes: 1961–1969, 1982–1984, and ongoing since 2018. These eruptive episodes resulted in extensive disturbance to surrounding trees. To characterize tree response over time as an indicator of geyser activity adjustments to climate variability, aerial and ground images were analyzed to document changes in tree coverage around the geyser since 1954. Radiocarbon dating of silicified tree remnants from within 14 m of the geyser vent was used to examine geyser response to possible variations in decadal to centennial precipitation patterns. We searched for atypical or absent growth rings in cores from live trees in years associated with large geyser eruptions. Photographs indicate that active eruptive phases have adversely affected trees up to 30 m from the vent, primarily in the dominant downwind direction. Radiocarbon dates indicate that the geyser formed before 1878, in contrast to the birthdate reported in historical documents. Further, the ages of the silicified trees cluster within three episodes that are temporally correlated with periods of relative drought in the Yellowstone region during the 15th–17th centuries. The discontinuous growth of trees around the geyser suggests that changes in eruptive patterns occur in response to decadal to multidecadal droughts. This inference is supported by the lack of silicified specimens with more than 20 annual rings and by the existence of atypical or missing rings in live trees during periods of extended geyser activity.

The Ediacaran metamorphosed banded iron formation (BIF) at Gohar Zamin mine (Gol-e-Gohar #3 anomaly), Sirjan (southeastern Iran): Perspective from ore structures, bulk ore-rock geochemistry and O-S-Pb isotopic signatures

Little is known about the occurrence of the Neoproterozoic banded iron formations (BIFs), except few cases of the glaciogenic Cryogenian BIFs. In this investigation, we describe an Ediacaran metamorphosed BIF interbedded with metamorphosed rocks. The Gohar Zamin iron deposit (643 Mt @ 54.3 % Fe, 2.04 % S, 0.12 % P) is hosted by mica schist, quartz schist and meta-basite that formed by metamorphism of the Fe-oxy-hydroxides, terrigenous (pelitic)-chemical (carbonate) sediments, silica gel and repeated phases of MORB-type submarine basic eruptions in shallow marine syn-rift basins. The sediments, basaltic eruptions and iron oxides were lithified to BIFs and then metamorphosed to greenschist facies during Cimmerian orogeny. The presence of macro-meso-microbandings in BIFs, coarse-grained quartz dropstones and magnetite clasts in the ores-host rocks, chemical index of alteration (CIA) (41.83 to 95.42 %) and positive correlation of Al2O3 against TiO2 and SiO2 values suggests a possible syn-glaciogenic BIF deposition. Fe/Ti-Al (Al + Fe + Mn), Fe-P, Co-Ni, V-Ti, V-Ni and Ni/ (Cr + Mn)-Ti + V diagrams suggest similarity to BIFs rather than the I-type granitoid magmatic-hydrothermal-skarn iron ores. REE + Y patterns display LREE depletion to slight enrichment, low-moderate Y/Ho ratios, HREE flat patterns, a nearly-zero to a seawater-like negative Ce anomaly and negative Eu anomaly. Such signatures may reflect low-T (300–200 °C) hydrothermal fluids for the origin of Fe-oxy-hydroxides formed by seawater-basaltic interaction and syn-glaciogenic meltwater influxes. Delta 18O values in magnetite-hematite (+3.3 to + 9.5 ‰) are in equilibrium with seawater and global BIFs. Delta 34S values in pyrite (+21.51 to + 26.59 ‰) reflect similarity to the Ediacaran pyrite composition formed by both thermal sulfate reduction (TSR) and bacterial sulfate reduction (BSR) processes. The radiogenic ratios of 206Pb/204Pb (19.228–25.105), 207Pb/204Pb (15.50–16.158) and 208Pb/204Pb (38.526–39.895) plot on the right side of 0.0 Ga geochron and were probably originated from the highly radiogenic zircon or galena clasts deposited by glaciogenic deposits. Geochemostratigraphy records zigzag elemental halos with the highest values of Fe (59.08 wt%) and Au (49.9 ppb). Exploration guides may be oriented to surficial sampling of the gossanized outcrops and heavy mineral surveys in drainage crosscutting the schistose rocks.

Monitoring the Mauna Loa (Hawaii) eruption of November–December 2022 from space: Results from GOES-R, Sentinel-2 and Landsat-8/9 observations

Mauna Loa, one of the most actives volcanoes on Earth, is a shield volcano, located on the Island of Hawaii (USA). On 27 November 2022, after about 38 years of quiescence, a new eruptive activity took place at the Moku‘āweoweocaldera, continuing in the following days (i.e. until 10 December) from the fissure vents opening on the Northeast Rift Zone.In this work, we investigate the Mauna Loa November − December 2022 eruption from space, integrating the information from different satellite sensors. The analysis of short-wave infrared (SWIR) data, at 10 min temporal resolution, from the Advanced Baseline Imager (ABI), aboard the Geostationary Operational Environmental Satellites − R series (GOES-R), performed through the Normalised Hotspot Indices (NHI), indicates that the Mauna Loa eruption started on 27 November in between 23:10–23:20 LT (28 November at 09:10–09:20 UTC). The same analysis shows the increase of thermal activity and its progressive reduction from the early morning of 28 November, in agreement with the eruption migration from the summit caldera to the Northeast Rift Zone. By analysing the second phase of eruption through SWIR data from the Multispectral Instrument (MSI) and Operational Land Imager (OLI), respectively aboard Sentinel-2 and Landsat 8/9 satellites, we estimated a maximum lava flow length of 17 km. Moreover, we retrieved values of the volcanic radiative power (VRP) up to 65 GW, and a time-averaged discharge rate (TADR) of ∼1000 (±500) m3/s. These results show that SWIR observations, at different spatial and temporal resolution, may give an important contribution to the monitoring, mapping and characterisation of intense lava effusions.

Origin of Fe-rich clay minerals in Early Devonian volcanic rocks of the Northern Minusa basin, Eastern Siberia

The formation of clay minerals in volcanic successions follows various evolutionary trends, the understanding of which is crucial for estimating the age of volcanism and the prospecting clay deposits. Early Devonian volcanics within the Byskar Series of the Minusa Depression (Khakassia) are variably altered to a range of phyllosilicate mineral assemblages. This study highlights the origin and formational conditions of the clay minerals, including illite, glauconite, smectite (saponite) and chlorite. Detailed mineralogical and chemical investigation identifies the predominant phyllosilicates, including 1 M illite, illite-smectite (R = 3), 1 M glauconite, smectite, chlorite and kaolinite within trachyandesite, trachyte, and rhyodacite. The phyllosilicates formed by the diagenetic transformation of volcanics after eruptive phases. Evolution trends of phyllosilicates depend largely on the composition of the volcanic substrate. The smectite to illite trend developed due to the dissolution of felsic volcanics and the alteration of smectites into illites with the K+, Al3+ and Mg2+ dominating the mineral formation system. The illites evolved by the substitution of Fe2+ and Mg2+ for Al3+ in the octahedral sheets of smectites. The K+, which was released due to devitrification of felsic substances, was introduced into the interlayer sites for compensating the layer charge originated by the isomorphic substitution in tetrahedral and octahedral sheets. The smectite to glauconite transition trend corresponds to the devitrification and dissolution of alkaline intermediate-felsic volcanics. Early formed dioctahedral smectites evolved into glauconite probably with the predominance of K+ and Fe2+/3+ ions in the formation environment. The substitution of Fe2+/3+ to Al3+ and Mg2+ in the octahedral sheets of smectite contributed to the formation of a layer charge and the entry of exchangeable K+ into the interlayers of glauconite. The third trend involved the formation of smectites (saponites) or chlorites within the intermediate volcanics possibly with Mg-rich but K-poor mineral system.

Interdisciplinary management of mpox-related local complications: report on a series of cases.

Monkeypox (mpox) is a viral zoonosis, and human-to-human transmission can result from close contact with the respiratory secretions and mucocutaneous lesions of an infected person. The prodromal phase is followed by an eruptive phase, with skin and/or mucosal lesions that progress through several stages at different sites. In this study, we describe the importance of interdisciplinary care management and follow-up of patients with complicated mpox. A cross-sectional study was conducted from May 2022 until August 2022 at a secondary hospital in Madrid (Spain). Out of 100 patients with mpox seen at this institution, we selected and analyzed 11 with local complications. All the patients were male at birth, and the mean age was 32 (30-42) years. The clinical manifestations included skin rash or mucosal lesions, fever, myalgia and lymphadenopathies. The most frequent local complications were pharyngitis associated with dysphagia, penile edema, infection of the mucocutaneous lesions, and ulceration of the genital lesions. A multidisciplinary team was created for the care of patients with complications secondary to mpox. The team comprised dermatologists and specialists in infectious diseases, preventive medicine, and emergency medicine. This approach improved the ability to diagnose and treat early with supportive, topical, and systemic treatment. In our center most of the cases were self-limiting, and none were life-threatening. An interdisciplinary response to a public health alert enhances the management of complex patients and should be implemented in successive outbreaks of mpox.

SO 2 emissions during the 2021 eruption of La Soufrière, St Vincent, revealed with back-trajectory analysis of TROPOMI imagery

Abstract Determining SO 2 emission time-series from explosive eruptions can provide important insights into the driving magmatic processes, however accurate measurements are difficult to collect. Satellite-based platforms provide SO 2 imagery, however translating this to the altitude- and time-resolved emission history required to unravel volcanic processes is a major challenge. This means SO 2 emission time-series are rarely quantified for major eruptions, producing a gap in our understanding of explosive volcanism. Here, we combine SO 2 imagery collected by the TROPOspheric Monitoring Instrument (TROPOMI) with PlumeTraj, a back-trajectory analysis toolkit, to reconstruct the SO 2 emission prior to, and during, the explosive eruption of La Soufrière volcano, St Vincent, in April 2021. Precursory SO 2 emissions were quantified the day before the eruption, with emission rates in agreement with ground-based measurements. We estimate initial magma sulfur contents by comparing the measured SO 2 emissions with erupted magma volumes, finding that the initial explosion was sulfur poor (730 ppm S) compared to the main eruption phase (up to 3400 ppm S). This suggests that the initial explosion cleared old, previously degassed magma resident in the shallow plumbing system, followed by the eruption of the main, mostly un-degassed magma source.

Complex monogenetic volcano in karst setting: Lechmine N'kettane volcano (Middle Atlas, Morocco)

The Lechmine N'kettane is a Quaternary volcano, located within the Middle Atlas Volcanic Field (MAVF) in central Morocco. It is built on the faulted contact between Liassic limestone and Plio-Quaternary fluvio-lacustrine deposits. In map-view it consists of an elliptical maar crater, surrounded by a tephra ring, within which a scoria cone is nested in its northern crater zone.The Lechmine N'Kettane volcano is monogenetic in the sense of its small eruptive product volume and lack of evidence of significant time breakthrough it grows. The volcano formed from an eruptive locus that migrated laterally and vertically within the short duration of the eruption in a zigzagging pattern, along a complex set of generally NE-SW and NW-SE-trending faults. It represents a perfect example of how a volcano form and evolve under the influence of a combination of specific factors such as the lithological characteristics of the substrate, its hydrogeological parameters, magma flux and the local structural framework of the country rocks.The petrographic, granulometric and morphological (including terrain modelling) analyses of the Lechmine N'kettane pyroclastic deposits show that it was constructed in four eruptive phases with variable eruptive styles. The first, relatively dry, phreatomagmatic phase, that took place on a NE-SW fault in the northeastern part of the crater, was generated by the interaction between the ascending basaltic magma with meteoric water in the karst aquifer hosted by the Liassic limestone. The second phase is represented by a magmatic scoria fallout deposit whose explosion locus moved westward, along the same NE-SW fault. During the third phase, the explosion center migrated southward, along a NNW-SSE fault, and produced the last phreatomagmatic event by interaction of magma and water-saturated Plio-Quaternary sediment. The fourth eruptive phase is a purely scoria event, corresponding to the construction of the nephelinitic scoria cone in the northwestern part of the tephra ring. Between eruptive products formed in respective eruptive phases no evidence was recognized to establish significant time gaps between their formation.

Power flux in the Schumann resonance band linked to the eruption of Tonga volcano on Jan. 15, 2022. (Two point measurements of Umov-Poynting vector)

Observations and model computations are compared of the Umov – Poynting vector (UPV) in the Schumann resonance (SR) band during the eruption of Tonga volcano on Jan. 15, 2022. The volcanogenic SR signals were recorded at the dual site: at the Cumiana observatory (44.96° N and 7.42° E) in the vertical electric field component and at the Sos Enattosobservatory (40.47° N, 9.48° E) in the two orthogonal ELF components of horizontal magnetic field. Initially, we present computations in the update model of the Earth – ionosphere cavity with the global lightning stroke distribution found by the Worldwide Lightning Location Network (WWLLN), which demonstrates the workability of our approach. The hodographs of UPV were obtained in the frequency (formally rigorous) and the time domain during the major phase of eruption. The positions of both of them suitably agree with each other and indicate on the wave arrival from the compact area around volcano during the major phase of Tonga eruption. The UPV magnitude indicates that the contribution from the Tonga volcano has elevated the observed level of ELF power flux by the factor of six relative to the quiet condition.

Episodic Magma Hammers for the 15 January 2022 Cataclysmic Eruption of Hunga Tonga‐Hunga Ha'apai

AbstractUnderstanding the forces and magma system dynamics on timescales of seconds to minutes remains challenging. In the January 2022 phreatoplinian Hunga Tonga‐Hunga Ha'apai eruption, four remarkably similar seismic subevents within a 5‐min interval occurred during the intensifying early eruptive phase. The subevents are similar in waveforms and durations (∼25 s each). Each subevent begins with an unusual negative P‐wave polarity which is inferred, using full‐wave seismic modeling, to be caused by an upward single‐force mechanism at the volcano created by a magma hammer likely in response to magma flow blockage/constriction during the early part of the eruption as discharge rapidly increased over orders of magnitude with concomitant conduit geometry evolution and instability. Our proposed episodic magma hammer model is consistent with thermodynamic and phase properties of the magmatic mixture, and yields an estimate of conduit mass flow in agreement with vent discharge rates derived from satellite imagery of plume heights.