A new ice core from the Eastern Summit of Mt. Elbrus, Caucasus, Russia

<p>Meteorological regime and glacier surface heat balance, GPR measurements of the ice thickness and seasonal snow cover were investigated in the crater of the Eastern Summit of Mt. Elbrus In the period from 18 to 30 August 2020 at 560 m a.s.l. On the base of preliminary data analysis, the predominance of fluctuations in the synoptic scale over the diurnal ones was revealed; high values of the average and maximum wind speed associated with the influence of jet currents and with the effects of leeward storms were identified; extremely high temporal variability of relative humidity and its very high deficit in cloudless conditions, which contributes to intensive evaporation and sublimation from the snow surface, were explored. The maximum ice thickness in the crater reaches 100 m, with an average of 45 m. A new 96.01 m ice core from glacier surface to bedrock has been recovered. The drilling speed varied from 11 to 1 m / h, decreasing on average with depth from 4.5 to 4.0 m / h. The thickness of the snow-firn strata is about 20 m, which is three times less than on the Western Plateau. The borehole temperature was measured. The temperature on the glacier bedrock was -0.6 °С. The calculated heat flux was 0.39 W/m2. Air sampling was carried out in the crater of the Eastern Summit of Elbrus and on the Garabashi glacier. The repeated measurement of the soil temperature in the fumarole field on the Elbrus Eastern Summit outer crater rim suggests that the temperature regime is stable.</p><p>The research was carried out on the territory of the Elbrus National Park with the financial support of the Russian Science Foundation (project 17-17-01270).</p>

Time-Lapse Landform Monitoring in the Pisciarelli (Campi Flegrei-Italy) Fumarole Field Using UAV Photogrammetry

The utility of new imaging technologies to better understand hazardous geological environments cannot be overstated. The combined use of unmanned aerial vehicles (UAV) and digital photogrammetry (DP) represents a rapidly evolving technique that permits geoscientists to obtain detailed spatial data. This can aid in rapid mapping and analyses of dynamic processes that are modifying contemporary landscapes, particularly through the creation of a time series of digital data to help monitor the geomorphological evolution of volcanic structures. Our study comprises a short-term (in geological terms) monitoring program of the dynamic and diffuse Pisciarelli degassing structure caused by the interplay between intensive rainfall and hydrothermal activity. This area, an unstable fumarole field located several hundred meters east of the Solfatara Crater of the Campi Flegrei caldera (southern Italy), is characterized by consistent soil degassing, fluid emission from ephemeral vents, and hot mud pools. This degassing activity is episodically accompanied by seismic swarms and macroscopic morphology changes such as the appearance of vigorously degassing vents, collapsing landslides, and bubbling mud. In late-2019 and 2020, we performed repeated photogrammetric UAV surveys using the Structure from Motion (SfM) technique. This approach allowed us to create dense 3D point clouds and digital orthophotos spanning one year of surveys. The results highlight the benefits of photogrammetry data using UAV for the accurate remote monitoring and mapping of active volcanoes and craters in harsh and dangerous environments.

Changes in CO2 Soil Degassing Style as a Possible Precursor to Volcanic Activity: The 2019 Case of Stromboli Paroxysmal Eruptions

Paroxysmal explosions are some of the most spectacular evidence of volcanism on Earth and are triggered by the rapid ascent of volatile-rich magma. These explosions often occur in persistently erupting basaltic volcanoes located in subduction zones and represent a major hazard due to the sudden occurrence and wide impact on the neighboring populations. However, the recognition of signals that forecast these blasts remains challenging even in the best-monitored volcanoes. Here, we present the results of the regular monitoring of soil CO2 flux from a fumarole field at the summit of Stromboli (Italy), highlighting that the 2016–2019 period was characterized by two important phases of strong increases of volatile output rate degassing (24 g m2 d−2 and 32 g m2 d−2, respectively) and moreover by significant changes in the degassing style few months before the last paroxysmal explosions occurred in the summer 2019 (3 July and 28 August). Establish that the deep portions of a volcano plumbing system are refilled by new volatiles-rich magma intruding from the mantle is therefore a key factor for forecasting eruptions and helping in recognizing possible precursors of paroxysmal explosions and could be highlighted by the monitoring of soil CO2 flux. The abrupt increase of degassing rate coupled with the strong increase of fluctuating signal (daily natural deviation) recorded during 2019 at Stromboli could be the key to predicting the occurrence of paroxysmal events.

New insights on the structural setting of the Pisciarelli fumarole field (Campi Flegrei caldera): implications for evolution and eruptive scenarios

<p>The Solfatara-Pisciarelli area, located in the active Campi Flegrei caldera (Italy) hosts an intense hydrothermal activity, whose shallower expression is controlled by a complex pattern of fractures and faults. Volcanological and structural studies may be the key to disclose the relationships between brittle structures and hydrothermal activity, as well as to understand the dynamic processes and possible eruption scenarios. For this purpose, we present the results of a volcanological and structural survey combined with Electrical Resistivity Tomography (ERT) and Self Potential data. Three ERT surveys has been performed in order to reconstruct the Pisciarelli structural setting and the relationships of the main fractures and faults with the underground fluid circulation. Two measured profiles crossing the main mud pool and fumaroles of Pisciarelli and has been repeated every three months to evaluate the possible influence of seasonal effects on the hydrothermal system. These profiles performed during the last year have been compared with a first ERT prospection carried on in correspondence of a 100 m long survey line, which crosses along the W-E direction the Pisciarelli permanent mud pool and its main fumarole. The comparison of the results with temperature, geochemical data and rainfall rates allowed to separate the areas dominated by seasonal effects from areas where deeper injected gasses cumulate in the subsoil. Further indication on the fluid circulation and structures derived by a mapping of the self-potential anomaly realized for the whole Solfatara-Pisciarelli area. The rocks exposed in the Pisciarelli area host a large number of faults and fractures, the latter often related to fault damage zones. Cross-cutting fault and fracture relationships and their relations with the volcanic sequences suggest that NW-SE and NE-SW trending faults are sealed by Solfatara deposits (4.28 ka); whereas E-W and N-S trending faults cross-cut the youngest volcanic succession (Astroni deposits, 4.25 ka). Several landslide deposits were recognized in the higher part of the Pisciarelli fumarole field, mainly due to intense rock fracturing, hydrothermal alteration, mud-pool activity and steep relieves surrounding the mud pool. Ancient landslide deposits overlying mud sediments, similar to those nowadays forming within the active mud pool, cropping out along the slope, at about 5 meters above the present mud pool level. New landslide phenomena could seal off the mud pool and fumaroles of Pisciarelli, with a possible consequence to trigger an hydrothermal explosions as described for other hydrothermal systems in the world.</p>

Deep Electrical Resistivity Tomography for a 3D picture of the most active sector of Campi Flegrei caldera

The central sector of the Campi Flegrei volcano, including the Solfatara maar and Pisciarelli fumarole field, is currently the most active area of the caldera as regards seismicity and gaseous emissions and it plays a significant role in the ongoing unrest. However, a general volcano-tectonic reconstruction of the entire sector is still missing. This work aims to depict, for the first time, the architecture of the area through the application of deep Electrical Resistivity Tomography. We reconstructed a three-dimensional resistivity model for the entire sector. Results provide useful elements to understand the present state of the system and the possible evolution of the volcanic activity and shed solid bases for any attempt to develop physical-mathematical models investigating the ongoing phenomena.

Composition and distribution of saturated hydrocarbons in the thermal waters and vapor–water mixture of the Mutnovskii geothermal field and Uzon caldera, Kamchatka

The paper presents data on the composition and molecular-mass distribution of saturated hydrocarbons in sterile vapor–water mixture from wells and in high-temperature springs in the Mutnovskii hydrothermal area and Uzon caldera. The condensate of the vapor–water mixture and thermal waters from the Mutnovskii area contain low-molecule n-alkanes, which were generated by thermogenic processes. The boiling mud pot of the Donnoe fumarole field typically contains hydrocarbons whose origin is likely related to thermocatalytic transformations of the biomass of thermophilic microorganisms. A separate type of the molecular-mass distribution is typical of the geyser in the caldera of Uzon volcano: this material contains n-alkanes, which were generated by two processes: chemical re-synthesis of floral organic remnants and biogenic synthesis with the probable involvement of bacteria and algae.

The ring-shaped thermal field of Stefanos crater, Nisyros Island: a conceptual model

Fumarole fields related to hydrothermal processes release the heat of the underground through permeable pathways. Thermal changes, therefore, are likely to depend also on the size and permeability variation of these pathways. There may be different explanations for the observed permeability changes, such as fault control, lithology, weathering/alteration, heterogeneous sediment accumulation/erosion and physical changes of the fluids (e.g., temperature and viscosity). A common difficulty, however, in surface temperature field studies at active volcanoes is that the parameters controlling the ascending routes of fluids are poorly constrained in general. Here we analyze the crater of Stefanos, Nisyros (Greece), and highlight complexities in the spatial pattern of the fumarole field related to permeability conditions. We combine high-resolution infrared mosaics and grain-size analysis of soils, aiming to elaborate parameters controlling the appearance of the fumarole field. We find a ring-shaped thermal field located within the explosion crater, which we interpret to reflect near-surface contrasts of the soil granulometry and volcanotectonic history at depth. We develop a conceptual model of how the ring-shaped thermal field formed at the Stefanos crater and similarly at other volcanic edifices, highlighting the importance of local permeability contrast that may increase or decrease the thermal fluid flux.