Search Results (5)

Catchment areas on volcanic territories in different regions are of great interest since they are enriched with nutrients that contribute significantly to coastal ecosystems. The Kamchatka Peninsula is one of the most active volcanic regions of the world; however, to date, the chemistry of its river waters and the state of its coastal ecosystems remain understudied in connection with volcanism. The two rivers under study are the largest in this region. The Kamchatka River, unlike the Penzhina River, drains volcanic territories, including the areas of the most active volcanoes of the Klyuchevskaya group of volcanoes and the Shiveluch Volcano. The mouth of the Kamchatka River has been shown to have DIP and DIN concentrations of 2.79–3.87 and 10.0–23.8 µM, respectively, during different seasons, which are comparable to rivers in urbanized areas with sewerage and agricultural sources of nutrients. It has been established that volcanoes form high concentrations of nutrients in the catchment area of the Kamchatka River. The Penzhina River has had very low DIP and DIN concentrations of 0.2–0.8 and 0.17–0.35 µM, respectively, near the mouth during different seasons, but high concentrations of DOC, at 5.9 mg/L in spring, which may be due to seasonal thawing of permafrost. During the period of increasing river discharge, seasonal phytoplankton blooms occur in spring and summer in bays of the same name, as shown using satellite data. The biomass of zooplankton in Penzhina Bay is at a level of 100 mg/L, while in Kamchatka Gulf, it exceeds 2000 mg/L. Thus, the biomass of zooplankton in the receiving basin, which is influenced by the runoff of the Kamchatka River with a volcanic catchment area in eastern Kamchatka, is 20 times higher than in the basin, which has a small nutrient flux with the river runoff in northwestern Kamchatka. This study demonstrates the connection between nutrient fluxes from a catchment area and the formation of seasonal phytoplankton blooms and high zooplankton biomass in the coastal area. We also study seasonal, year-to-year, and climatic variability of water discharges and hydrometeorological conditions to understand how nutrient fluxes can change in the foreseeable future and influence coastal ecosystems. Full article

The results of the observations of atmospherics and whistlers initiated by high-altitude electrical discharges that occurred during the eruption of the Kamchatka volcanoes (Bezymianny and Shiveluch (Russia)) on 7 and 10 April 2023 are presented. Recording of atmospherics and associated whistlers was carried out by a VLF (very low frequencies) radio direction finder. Two-hop whistlers were identified by dispersion coefficient, which corresponded to the double passage of the signal from Kamchatka to Australia and back. The heights of the electric discharges were determined by means of interferograms of direct and reflected from the ionosphere radiofrequency atmospherics. The high-altitude distribution of an electric discharge is obtained, the penetration of which into the ionosphere is responsible for the generation of whistlers. The characteristics of volcanic electrical discharges and whistlers can be used to estimate the height of an explosive eruption. Full article

The full range of effects of strong volcanic eruptions on the electrical characteristics of the atmosphere is not yet fully understood. On the 10 April 2023, the largest eruption in recent decades of the Shiveluch volcano in Kamchatka occurred. At the same time, a sharp increase in electron concentration was observed in the F layer of the ionosphere above the volcano. Simultaneously, at a distance of 450 km from the volcano, an intense anomaly was observed in the vertical component of the electric field potential gradient in the surface atmosphere. At this distance, the anomaly could not have been caused by a space charge of volcanic ash. The article examines the atmospheric–electrical effects of a volcanic eruption and proposes a physical mechanism for these phenomena. The formation of strong electric field positive jump as result of volcano eruption was confirmed by the consecutive Shiveluch volcano eruption on the 18 August 2024. Full article

The paper is devoted to the description of observations over atmospheric and electric effects from volcanic eruptions on Kamchatka peninsula (Russia) and perspectives of their development. To collect information about atmospheric-electric effects accompanying the eruptions of Kamchatka volcanoes, three sensor networks and a VLF radio direction finding station are used. The World Wide Lightning Location Network (WWLLN) provides information on high-current lightning discharges that occur during the development of an eruptive cloud (EC). Variations in the electric field of the atmosphere (AEF $E_z$ ), during the passage of EC, were obtained by a network of electric field mills at the sites for volcanic activity observations. Seismic detector network was used to make precision reference to the eruptions. Based on the data obtained, a description is given of the dynamics of eruptions of the most active volcanoes in Kamchatka and the Northern Kuril Islands (Shiveluch, Bezymianny, Ebeko). The paper presents a simulation of the response of the atmospheric electric field, which showed that the approximation by the field of distributed charges makes it possible to estimate the volume charges of EC. The fact of a multi-stage volcanic thunderstorm is confirmed. The first stage is associated with the formation of an eruptive column, and the second with the emergence, development and transfer of EC. Registration of electrical and electromagnetic processes in eruptive clouds can be one of the components of complex observations of volcanic eruptions in order to assess the ash hazard for air transport. Full article

Shiveluch (Kamchatka, Russia) is the most active andesitic volcano of the Kuril-Kamchatka arc, typically exhibiting near-continual high-temperature fumarolic activity and periods of exogenous lava dome emplacement punctuated by discrete large explosive eruptions. These eruptions can produce large pyroclastic flow (PF) deposits, which are common on the southern flank of the volcano. Since 2000, six explosive eruptions have occurred that generated ash fall and PF deposits. Over this same time period, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument has been acquiring image-based visible/near infrared (VNIR), short wave infrared (SWIR) and thermal infrared (TIR) data globally, with a particular emphasis on active volcanoes. Shiveluch was selected as an ASTER target of interest early in the mission because of its frequent activity and potential impact to northern Pacific air transportation. The north Pacific ASTER archive was queried for Shiveluch data and we present results from 2000 to 2009 that documents three large PF deposits emplaced on 19 May 2001, 9 May 2004, and 28 February 2005. The long-term archive of infrared data provides an excellent record on the changing activity and eruption state of the volcano. Full article