Эксплозивная активность вулкана Атсонупури в позднем голоцене (о. Итуруп, Южные Курильские острова): предварительные результаты

<p>Strong explosive eruptions of volcanoes are the most dangerous for aircraft because they can produce in a few hours or days to the atmosphere and the stratosphere till several cubic kilometers of volcanic ash and aerosols. Ash plumes and the clouds, depending on the power of the eruption, the strength and wind speed, can travel thousands of kilometers from the volcano for several days, remaining hazardous to aircraft, as the melting temperature of small particles of ash below the operating temperature of jet engines.</p><p>There are 30 active volcanoes in the Kamchatka, and several of them are continuously active. Scientists of KVERT monitor Kamchatkan volcanoes since 1993. In 2020, four of these volcanoes (Sheveluch, Klyuchevskoy, Bezymianny, and Karymsky) had strong and moderate explosive eruptions.</p><p>The eruptive activity of Sheveluch volcano began since 1980 (growth of the lava dome) and it is continuing at present. In 2020, strong explosions sent ash up to 7-10 km a.s.l. on 08 April, and 22 and 29 December. Ash from explosions rose up to 5-6 km a.s.l. on 13 June, and 24 December. Ash plumes extended more 625 km mainly to the south-east of the volcano. A form of resuspended ash was observed on 20 April, 28 June, 24 August, and 07-10 October: ash plumes extended for 310 km to the northeast and southeast of the volcano. Activity of Sheveluch was dangerous to international and local aviation.</p><p>Two moderate explosive-effusive eruptions of Klyuchevskoy volcano occurred in 2020: first from 01 November 2019 till 03 July 2020, and second from 30 September, it is continuing in 2021. Explosions sent ash up to 7 km a.s.l., gas-steam plumes containing some amount of ash extended for 465 km to the different directions of the volcano. The lava flows moved along Apakhonchichsky and Kozyrevsky chutes. Activity of the volcano was dangerous to local aviation.</p><p>The strong explosive eruption of Bezymianny volcano occurred on 21 October: explosions sent ash up to 11 km a.s.l., the large ash cloud was located over Klyuchevskoy group of volcanoes long time and later drifted up to1200 km to the southeast of the volcano. Activity of the volcano was dangerous to international and local aviation.</p><p>Eruptive activity of Karymsky volcano was uneven in 2020: ash explosions were observed from one (June) to seven (October) days a month, for five months the volcano was quiet. Explosions rose ash up to 8 km a.s.l. (08 November), ash plumes and clouds drifted for 380 km to the different directions of the volcano. The eruptive volcanic activity was observed in April, May, June, July, October, November, and December. Activity of Karymsky was dangerous to international and local aviation.</p>

<p>Strong explosive eruptions of volcanoes are the most dangerous for aircraft because they can produce in a few hours or days to the atmosphere and the stratosphere till several cubic kilometers of volcanic ash and aerosols. Ash plumes and the clouds, depending on the power of the eruption, the strength and wind speed, can travel thousands of kilometers from the volcano for several days, remaining hazardous to aircraft, as the melting temperature of small particles of ash below the operating temperature of jet engines.</p><p>There are 30 active volcanoes in the Kamchatka; scientists of KVERT monitor these volcanoes since 1993. Description of volcanic eruptions is based on video monitoring and various satellite data from the information system "Remote monitoring of the activity of volcanoes of the Kamchatka and the Kuriles" (VolSatView, http://kamchatka.volcanoes.smislab.ru). In 2021, three volcanoes (Sheveluch, Klyuchevskoy, and Karymsky) had eruptions.</p><p>The eruptive activity of Sheveluch (growth of the lava dome) is continuing since 1980. In 2021, explosions sent ash up to 7.5 km a.s.l. mainly in August and December; ash plumes were extending more 380 km to the different directions of the volcano. A new plastic lava block Dolphin-2 squeezed at the dome from February till July 2021. Resuspended ash was observed on 02-03 April, 06-07 July, 13-14 and 22 August, and 06-07 and 21 October: ash plumes were extending for 400 km to the east and southeast of the volcano. Satellite data by KVERT showed a thermal anomaly over the volcano all year. Activity of the volcano was dangerous to local aviation.</p><p>The terminal explosive-effusive eruptions of Klyuchevskoy volcano took place from 30 September, 2020 to 08 February, 2021. Explosions sent ash up to 8 km a.s.l., gas-steam plumes containing some amount of ash were extending for 500 km to the different directions of the volcano. The lava flows moved along Apakhonchichsky and Kozyrevsky chutes. Satellite data by KVERT showed a thermal anomaly over the volcano all year. The lateral break on the northwestern slope of Klyuchevskoy at an altitude of 2.8 km a.s.l. lasted from 17 February to 20 March, 2021: lava effused from two cracks, a cinder cone 60 m high was formed. By February 23, lava flows 1.2 km long reached the Erman glacier, mud flows passed about 30 km. Activity of the volcano was dangerous to international and local aviation.</p><p>Eruptive activity of Karymsky volcano was uneven in 2021. According to satellite data, the strong ash explosions were observed: on 04 April (8.5 km a.s.l.), 10 September (7 km a.s.l.), 03 November (11 km a.s.l.), and 06, 13, and 18 November (8 km a.s.l.); in the other months explosions sent ash up to 6 km a.s.l.; ash plumes and clouds drifted for 2700 km to the different directions from the volcano. The thermal anomaly over the volcano was recorded on satellite images from time to time. Activity of the volcano was dangerous to international and local aviation.</p>

Sulphur eruptions at Volcán Poás, Costa Rica

The collaborative research UNIFI–University of the Azores (IVAR) focused on the detection and characterization of events injecting energy into the atmosphere and allowed to analyze of the Grímsvötn volcano eruptive activity (Iceland) and Mt. Etna and Stromboli volcanoes (Italy) by several Stations (among which IS42) of the CTBTO’s International Monitoring System (IMS). Grímsvötn volcano, located under the Vatnajökull glacier, is the most active Icelandic volcano. The May 2011 explosive eruption broke the ice-covering and turned into sub-aerial, ejecting ash into the atmosphere and restricting flights across Northwestern Europe and the North Atlantic region. Mt. Etna, located in Sicily Island (Italy), is Europe’s largest and most active volcano. It is typically effusive with explosive episodes, and lava fountaining activity has recently produced high eruptive plumes causing an impact on local air traffic and nearby airports and cities. Finally, Stromboli volcano (Italy), located in one of the Aeolian Islands (Italy) with the same name, is one of the most active volcanoes on Earth, with sustained explosive activity and permanent degassing. A strong explosive event characterized by two distinct explosions occurred on July 3rd, 2019. In this study, we describe a multiple-detections analysis of (a) the May 2011 Grímsvötn eruption as observed at IS42 and other infrasound stations and its correlations with on-site observations; (b) the Mt. Etna eruptive activity of the May–September 2011 and the 2016 eruptions, as observed at IS42 and other stations, compared with near-source observations; and (c) the Stromboli July 3rd, 2019 event detections from IS42 and other IMS infrasound stations. We relate those results with events listed in the CTBTO Reviewed Event Bulletin (REB) to evaluate the potential of the IMS network in detecting and identifying sources of volcanic activity. In the framework of earth-based volcanic monitoring techniques, infrasound is a unique technology with the potential to detect explosive eruptions at great distances. Furthermore, simultaneous infrasound recording in near- and far-field represents a substantial improvement in the characterization of explosive sources.

In our paper we represent the first data on the Holocene explosive activity of Zavaritsky volcano, the largest caldera center on Simushir Island (Central Kuriles). For the first time, we reconstructed the chronology of explosive eruptions of this volcanic center for the past 10 000 years, as well as estimate the parameters of its largest eruptions. In total, more than 40 tephra horizons have been identified, which allows us to estimate the frequency of eruptions: 1 event in 250 years. Constructed age model allowed us to determine the age of most eruptions. Volcanic glasses of Holocene tephras correspond in composition to low-potassium basaltic andesite-rhyolites, while the very low K2O content makes it possible to fairly confidently distinguish Zavaritsky tephra not only from the tephra of neighboring moderate-potassium volcanoes, but also from the tephra of other low-potassium volcanoes of the Kuril-Kamchatka Island arc. Holocene activity of Zavaritsky volcano started with two powerful eruptions with a conservatively estimated magnitude (M) of 6.4 and 5.6, which occurred about 9.5 and 9.2 thousand years ago (ka BP). Tephra from the first eruption (ZV-1) spread to the northeast and was found as far as northwestern North America. Tephra from the second powerful eruption (ZV-3) spread north and was found in sediments of the Sea of Okhotsk. Volcanic glass of ZV-1 tephra is characterized by rhyolitic composition with the highest SiO2 content (72.5‒74 wt. %). Glasses of the ZV-3 tephra varied in composition from dacites to rhyodacites (65‒71.9 wt. % SiO2). The products of subsequent eruptions were represented by scoria with glasses of dacite — andesite and basaltic andesite composition. Dacitic glasses reappeared only in the tephra of the last large explosive eruption that occurred early before the middle of the 19th century. Our studies revealed the catastrophic explosive eruptions of Zavaritsky volcano during the Early Holocene and sustained activity of this eruptive center throughout the Holocene. The appearance of high-silica glasses in the tephra of the last powerful eruption (ZV-40) indicates a possible strong eruption in the near future.

The article presents memories of the author’s work on the Iturup Island (in 1988 and 1990) together with Yu. V. Knorozov, the prominent Soviet/Russian specialist in ancient writing systems and ethnic semiotics. A brief review of archaeological sites and rock images found and studied by him on the Iturup Island in 1979–1990 is given. One of the main tasks was the search for the traces left by Ainu and more ancient populations of the Kuriles, mainly rock images and carvings. Before works by Yu. V. Knorozov in 1979–1990, archaeological investigation in the southern Kurile Islands were conducted sporadically, without clear program. Yu. V. Knorozov found, analyzed and interpreted signs and symbols carved on the boulders and other rock surfaces of the Iturup Island. He also collected large amount of samples for radiocarbon dating, and this allowed to generate for the first time the chronological framework for ancient cultural complexes of the southern Kuriles. Yu. V. Knorozov found and preliminarily studied the Yankito 2, the oldest archaeological site in the entire Kuriles. The importance of the Yu. V. Knorozov’s contribution to the investigation of the distant past of the southern Kuril Islands and the spiritual world of their inhabitants in antiquity is emphasized.

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.

Iturup Island (in southern Kuril Islands) and southeastern Sakhalin Island are known by the highest catches of salmons within the Sakhalin-Kuril region. The timing of pink salmon mass return to Iturup is 5–10 days later than to Sakhalin, and the females returned to Iturup have higher relative individual fecundity, on average. In 2014, an unexpected increase of pink salmon catches occurred on southeastern Sakhalin Island, with a simultaneous sharp decrease of the catches on Iturup Island. Assumption on appearance of Kuril pink salmon in the Sakhalin waters was confirmed by analysis of the scale parameters (number of sclerites and intercirculi distance in the first-year scale zone), dynamics of catches, and individual fecundity of females. Sharp opposite changes of the pink salmon catch dynamics were noted again for these areas in 2017 and 2018. Such changes of pink salmon abundance could be reasoned by environmental conditions of reproduction in these areas or new redistribution between two areas. To clarify the issue, complex analysis (same as for 2014) was applied for pink salmon at southeastern Sakhalin and Iturup in 2017 and 2018 (187 and 215 fish samples from Sakhalin and 194 and 152 fish samples from Iturup in these two years, respectively). The results were interpreted following the hypothesis of fluctuating stocks. Taking into account the complex of traits, there is concluded that the assumption about redistribution of pink salmon between southeastern Sakhalin and Iturup Island in 2017 and 2018 is untenable.

Every now and again Earth experiences tremendous explosive volcanic eruptions, considerably bigger than the largest witnessed in historic times. Those yielding more than 450km3 of magma have been called super-eruptions. The record of such eruptions is incomplete; the most recent known example occurred 26000 years ago. It is more likely that the Earth will next experience a super-eruption than an impact from a large meteorite greater than 1km in diameter. Depending on where the volcano is located, the effects will be felt globally or at least by a whole hemisphere. Large areas will be devastated by pyroclastic flow deposits, and the more widely dispersed ash falls will be laid down over continent-sized areas. The most widespread effects will be derived from volcanic gases, sulphur gases being particularly important. This gas is converted into sulphuric acid aerosols in the stratosphere and layers of aerosol can cover the global atmosphere within a few weeks to months. These remain for several years and affect atmospheric circulation causing surface temperature to fall in many regions. Effects include temporary reductions in light levels and severe and unseasonable weather (including cool summers and colder-than-normal winters). Some aspects of the understanding and prediction of super-eruptions are problematic because they are well outside modern experience. Our global society is now very different to that affected by past, modest-sized volcanic activity and is highly vulnerable to catastrophic damage of infrastructure by natural disasters. Major disruption of services that society depends upon can be expected for periods of months to, perhaps, years after the next very large explosive eruption and the cost to global financial markets will be high and sustained.

Characteristics of early and late migrants of pink salmon Oncorhynchus gorbuscha that spawned in the rivers of the coast of Aniva Bay (southern Sakhalin) and Iturup Island (southern Kuril Islands) are described. Upstream migration of the late form is characterized by the presence of large exemplars, especially males, and increasing proportion of these fishes in the catches. Absolute fecundity of the females of the early and late forms can be similar (Iturup Island) or different (Aniva Bay), but relative fecundity is lower in the females of the late form in both regions. Production of a larger number of eggs by the females of the early form is associated with a larger level of mortality: the abundance of the early form is comparatively low, and substantial annual variation of the abundance is registered. Relative abundance of pink salmon from the temporal groups depends mainly on reproductive conditions during the freshwater part of their life cycle. Analysis of size composition of the fish conducted over many years shows a trend in the ratio between the body lengths of males and females: unfavorable foraging conditions (and slower growth rate) lead to the appearance of females that are larger than males. To take into account a positive correlation between the body length and fecundity of females, this feature is regarded as a compensatory reaction of the population directed to more intensive reproduction at poor foraging conditions.

—This paper describes a set of studies performed at a thermal manifestation (Lake Utinaya Banya) on the Iturup Island (Kuril Islands). These studies include bathymetric survey of the lake basin, geometric leveling across the lake, pitting, sampling of thermal waters from the lake and springs, hydrochemical research, and isotopic analysis of oxygen and hydrogen in the lake water. It is suggested by the shape of the lake basin (close to lenticular with a significant concentric depression), the underwater gas-hydrothermal vents, the bank along the perimeter of the lake basin, and the presence of several layers of clastic deposits at the top of the rampart that the lake was formed by a hydrothermal eruption. The lake temperature has remained constant over the years and ranges on average from 25 to 15 °C, depending on the season. The water of Lake Utinaya Banya is represented by acidic, sulfate calcium, and low-mineralized waters.

The establishment of volcanic risk in any district is usually likely to be a necessary preliminary to the detailed investigation and observation required for the prediction of volcanic eruptions. Volcanoes may be well known in their habits and studied in detail, as at Hawaii; they may be known as active or intermittently active volcanoes though not studied in detail, like Mt Ruapehu in New Zealand; or they may be regarded as dormant or even extinct. It is with this last type that this paper is chiefly concerned. Detailed geological mapping of volcanic deposits in an area, combined with radiocarbon or other adequate dating technique, can now indicate the existence of volcanic risk in areas that might otherwise be regarded as extinct. In New Zealand four active volcanic districts have been inferred where there are no visibly active volcanoes. These are Kaikohe, Auckland, Taranaki, and the central volcanic region of Taupo and Rotorua. At Taupo and Rotorua there is a mantle of volcanic ash spread over about 10,000 square miles as the result of a series of explosive eruptions of rhyolitic pumice. Mapping of these deposits has shown that those near Rotorua were erupted from vents within the Okataina Volcanic Centre, and those near Taupo from a previously unrecognised volcanic centre on the north-east side of Lake Taupo (Taupo Volcanic Centre). Quiescent periods between eruptions are represented by a number of fossil topsoils buried within the sequence of ash deposits. Both volcanic centres have eruptive histories throughout the latter part of the Pleistocene, and appear to have been the sources for some of the great ignimbrite flows of the region. At both localities the most recent activity (apart from the building of domes in the Okataina Volcanic Centre) has been the explosive eruption of pumice ash, and this is taken to be the present phase of activity. Radiocarbon dating has now established ages for many of the eruptions, and it can be inferred from the periodicity of these that the phase is not yet over, so that further eruptions may be expected. The last eruption was that of Tarawera near Rotorua in 1886; at Taupo the last took place about A.D. 120. The latter was probably of greater magnitude than any other of historic time. Many of the eruptions if they occurred today would be regarded as catastrofhic. The same type of eruptive sequence is possibly common to other rhyolitic areas, and the recognition of volcanoes and volcanic centres that must still be regarded as active, or that were previously not known to exist, is important. It is then possible to plan detailed geological and geophysical investigations in these areas to detect signs of any impending eruptions.

The United States ranks as one of the top countries in the world in the number of young, active volcanoes within its borders. The United States, including the Commonwealth of the Northern Mariana Islands, is home to approximately 170 geologically active (age <10,000 years) volcanoes. As our review of the record shows, 30 of these volcanoes have erupted since 1980, many repeatedly. In addition to producing eruptions, many U.S. volcanoes exhibit periods of anomalous activity, unrest, that do not culminate in eruptions. Monitoring volcanic activity in the United States is the responsibility of the U.S. Geological Survey (USGS) Volcano Hazards Program (VHP) and is accomplished with academic, Federal, and State partners. The VHP supports five Volcano Observatories - the Alaska Volcano Observatory (AVO), Cascades Volcano Observatory (CVO), Yellowstone Volcano Observatory (YVO), Long Valley Observatory (LVO), and Hawaiian Volcano Observatory (HVO). With the exception of HVO, which was established in 1912, the U.S. Volcano Observatories have been established in the past 27 years in response to specific volcanic eruptions or sustained levels of unrest. As understanding of volcanic activity and hazards has grown over the years, so have the extent and types of monitoring networks and techniques available to detect early signs of anomalous volcanic behavior. This increased capability is providing us with a more accurate gauge of volcanic activity in the United States. The purpose of this report is to (1) document the range of volcanic activity that U.S. Volcano Observatories have dealt with, beginning with the 1980 eruption of Mount St. Helens, (2) describe some overall characteristics of the activity, and (3) serve as a quick reference to pertinent published literature on the eruptions and unrest documented in this report.

The volcanic response to deglaciation: Evidence from glaciated arcs and a reassessment of global eruption records

Large explosive eruptions of volcanoes pose the highest hazard to modern jet flights, because such eruptions can eject as much as several cubic kilometers of volcanic ash and aerosol into the atmosphere during a few hours or days. The year 2016 saw eruptions on 5 of the 30 active Kamchatka volcanoes (Sheveluch, Klyuchevskoy, Bezymianny, Karymsky, and Zhupanovsky) and on 3 of the 6 active volcanoes that exist on the North Kuril Islands (Alaid, Ebeko, and Chikurachki). Effusive activity was observed on Sheveluch, Klyuchevskoy, Bezymianny, and Alaid. All volcanoes showed explosive activity. The large explosive events mostly occurred from September through December (Sheveluch), a moderate ash emission accompanied the entire Klyuchevskoy eruption in March–November, and explosive activity of Karymsky, Zhupanovsky, Alaid, and Chikurachki was mostly observed in the earlier half of the year. The ash ejected in 2016 covered a total area of 600 000 km2, with 460 000 km2 of this being due to Kamchatka volcanoes and 140 000 km2 to the eruptions of the North Kuril volcanoes. The activity of Sheveluch, Klyuchevskoy, and Zhupanovsky was dangerous to international and local flights, because the explosions sent ash to heights of 10–12 km above sea level, while the eruptions of Bezymianny, Karymsky, Alaid, Ebeko, and Chikurachki were dangerous for local flights, since the ash did not rise higher than 5 km above sea level.