О наступании ледников в условиях вулканической деятельности вулкана Ключевской (Камчатка)

New data on continuing advance of the Kamchatka glaciers Erman, Vlodavets, Sopochny, Schmidt, and Bogdanovich were obtained as a result of analysis of aerospace information taken at different times. Glacier Erman advances during the past 70  years (1945–2016). Over the period from 1949 to 2016, its area increased by 4.7 km2 and the length – by 3.3 km (from 18.2 to 21.5 km). The highest speed of advancing had been estimated for the Schmidt glacier, in 2007–2013 it exceeded 100 m/year. We had identified a new isolated glacier between glaciers Erman and Schmidt, named as the Obvalny (the «Avalanche») glacier, since in 1945 this glacier was buried under volcanic-avalanche deposits resulted from the Klyuchevskaya volcano eruption. In 1975–2016, the Obvalny glacier advanced over a distance of about 1700 m. Also, we had found more 30 ice-rock massifs («wandering glaciers») on slopes of the Klyuchevskaya volcano. Their contours looked like drops or tongues, and some of them advanced in the frontal zone. From 2002 to 2016, the «wandering glacier» in the upper reaches of river Glubokaya (eastern sector of the volcano) advanced for 740 m (55 m/year). Advancing of glaciers here is a consequence of lateral and terminal eruptions of the Klyuchevskaya volcano in XX and XXI centuries. Erman Glacier, glacier advance, Klyuchevskaya volcano, lateral eruption, space images, volcanic and rock avalanche deposits, «wandering glaciers».На основе анализа разновременной аэрокосмической информации за период 1949–2016 гг. полу- чены новые данные о современном состоянии и наступании ледников района вулкана Ключев- ской – Эрмана, Влодавца, Сопочного, Шмидта, Богдановича и безымянных «блуждающих ледников». Площадь ледника Эрмана увеличилась на 4,7 км2, а длина достигла 21,5 км. Самые высокие темпы наступания – до 100 м/год – характерны для ледника Шмидта. Наступание ледников есть следствие латеральных и терминальных извержений вулкана Ключевской в XX и XXI вв

Эволюция озёр у ледника Джикиуганкез (Северное Приэльбрусье) в 1957–2020 гг. с учётом подземных каналов стока

Evolution of lakes near the Dzhikiugankez Glacier in the north of Elbrus for the period of 1957–2020 was studied using a comparative interpretation of aerial and satellite images as well as aerial and ground surveys in 2007–2018. Within this period the area of the Dzhikiugankez Glacier (43,35 N, 42,53 E) decreased by 8.2 km2. On the territory previously occupied by the glacier and close to it, 19 lakes appeared at different times, which dynamically developed and broke through. The lakes cover the area of 0.43 km2, that equals to 5.21% of the total icefree area. The average area of the lakes is 26.6 thousand m2. The maximum (the lake East Birdzhaly) is 89 thousand m2. In total there were six lakes larger than 25 thousand m2. They are concentrated in depressions on the surface of an ancient lava flow dammed by glaciers, dead ices and moraine lines. At a certain stage in the evolution of lakes, water from them penetrated through these barriers and, thus, formed subglacial and underground drainage channels. In 2013, during helicopter flights, an underground drainage channel with a length of more than 80 m was detected in the moraine line around the Lake «Podkova». The survey made possible to determine decreasing in the lake level by 2 m, and the accumulation of water with a volume of up to 48 thousand m3 in the cavities of the moraine massif, until it reaches the outer slope. The accumulated volume of water interflowed through the underground channel gradually, but despite the pot-holes on its bottom, no mudflow happened in the valley. Although in another case, the formation of an underground drainage channel from the Severnoye Chungurchat Lake was accompanied by a lake breakthrough and a mudflow. Other characteristic features of the evolution of lakes and changes in the direction of drainage from glaciers are also analyzed in the paper.По данным дешифрирования аэрофотоснимков и космических снимков за 1957–2020 гг., а также полевых наблюдений и вертолётных облётов определены особенности эволюции озёр у ледника Джикиуганкез и механизмы их прорыва, в том числе по подземным каналам. На примере озёр Подкова, Северное Чунгурчат и Балык Южное показано, что формирование подземных каналов стока не обязательно приводит к сходу селевых потоков, однако даже небольшие озёра могут быть очагами значительных селей

Активизация обвалов на Центральном Кавказе и их влияние на динамику ледников и селевые процессы

We analyzed multi-time satellite images of the Central Caucasus glacial zone and interpreted more than thirty rock avalanche events in the 21st century with a total damage area of more than 25 km2 (including the collapse zone of the Kolka Glacier disaster). The highest rock and rock-ice avalanche activity is detected in the section of The Greater Caucasus range (northern and southern slopes) with a length of about 20 km between the Bashkara and Kulaktau peaks (16 rock avalanches) and in the section of the Kazbek-Dzhimaray Massif (series of rock avalanches to the surface of Kolka, Suatisi and Devdoraki glaciers). The feature of the rock and ice-rock avalanches is the large runout distance. For 12 events (about 40%) the distance was more than 2000 m. One ice-rock avalanche from the Mount Kazbek (excluding the Kolka Glacier disaster in 2002) reached the runout distance more than 10 km. In some areas, the rock avalanches occurred several times. In particular, a large number of avalanches were in the cirque of the Kolka Glacier; the last of them at the end of 2019. Thrice шт each case, rock avalanches originated from Mount Bashkara, in the cirques of the Murkvam Glacier, the East Shtulu Glacier, and the Devdoraki Glacier. Ice and rock avalanches were the initial stage of the complex process of the Kolka Glacier disaster and following catastrophic glacial debris flow in the Genaldon/Gizeldon River valley in 2002. Also, they were causes of glacier surges, formation of dammed lakes, and debris flows. As a result of the collapse of the hanging glacier and bedrock, the former right tributary of the Kolka Glacier surged to 200 m in 2006. Ice-rock avalanche from Mount Kazbek in 2014 load up the former right tributary of the Devdoraki Glacier and caused its advancing in 2015–2019, at a distance of more than 400 m. The avalanches caused catastrophic debris flows in the Amilishka/Kabakhi River valley in 2014, the Mestiachala River valley in 2019. Rock avalanches can cause outbursts of lakes and debris flows. Two dammed lakes formed as a result of the rock avalanche from the cirque above the Seri Glacier in the Tviberi River valley of the in May 2016. The lakes (total area was more than 0.05 km2) have outburst at the end of August 2017 after heavy rains. Rock avalanches of the 20th century led to an abrupt deceleration in the retreat of the Yusengi, Bartuytsete, East Shtulu and Mosota glaciers. The formation of rock avalanches in the 21st century took place at high altitudes (an average of about 3900 m). Possibly, the reason was associated with an increase of the «0» isotherm and of the high border of the zone of intense frost weathering due to climate warming. Some rock avalanches in the section of the Kazbek-Dzhimarai Massif have been caused by endogenous factors (seismicity and volcanism).На основе анализа разновременных космических снимков приведены данные о 32 обвалах в ледниковой зоне Центрального Кавказа в ХХI в. Половина из них сосредоточена на участке северного и южного склонов Главного Кавказского хребта восточнее горы Башкара. Отмечена высокая активность обвалов в 2019 г., показано влияние обвалов на динамику ледников и селевые процессы

ON THE RESTRUCTURING OF DRAINAGE NETWORK OF THE BASE OF MOUNT ELBRUS

From 1957 to 2010, glaciers at the northeast foothills of Elbrus have significantly decreased in size. The area of the glaciers Birdzhalychiran and Chungurchatchiran have shrunk by 5.7 square kilometers. The shrinking in glacier thickness and the reduction in flow of glacier waters have resulted in the formation of barriers that look like riegels; at the same time, barriers that formed by dead ice of the medial moraine disappeared. This situation induced the constant change of glacial flow direction and the breach of lakes. The prediction for this area gives forthcoming radical reforming of the water network because of disappearance of the medial moraine ridge and the joining of the right-hand side of the river Birdzhaly-Su to the merging point of the river Kara-Kaya-Su

On advancing of glaciers due to activity of the Klyuchevskaya Sopka volcano (Kamchatka)

New data on continuing advance of the Kamchatka glaciers Erman, Vlodavets, Sopochny, Schmidt, and Bogdanovich were obtained as a result of analysis of aerospace information taken at different times. Glacier Erman advances during the past 70  years (1945–2016). Over the period from 1949 to 2016, its area increased by 4.7 km2 and the length – by 3.3 km (from 18.2 to 21.5 km). The highest speed of advancing had been estimated for the Schmidt glacier, in 2007–2013 it exceeded 100 m/year. We had identified a new isolated glacier between glaciers Erman and Schmidt, named as the Obvalny (the «Avalanche») glacier, since in 1945 this glacier was buried under volcanic-avalanche deposits resulted from the Klyuchevskaya volcano eruption. In 1975–2016, the Obvalny glacier advanced over a distance of about 1700 m. Also, we had found more 30 ice-rock massifs («wandering glaciers») on slopes of the Klyuchevskaya volcano. Their contours looked like drops or tongues, and some of them advanced in the frontal zone. From 2002 to 2016, the «wandering glacier» in the upper reaches of river Glubokaya (eastern sector of the volcano) advanced for 740 m (55 m/year). Advancing of glaciers here is a consequence of lateral and terminal eruptions of the Klyuchevskaya volcano in XX and XXI centuries. Erman Glacier, glacier advance, Klyuchevskaya volcano, lateral eruption, space images, volcanic and rock avalanche deposits, «wandering glaciers»

О ПЕРЕСТРОЙКЕ ГИДРОГРАФИЧЕСКОЙ СЕТИ СЕВЕРО-ВОСТОЧНОГО ПОДНОЖИЯ ЭЛЬБРУСА

From 1957 to 2010, glaciers at the northeast foothills of Elbrus have significantly decreased in size. The area of the glaciers Birdzhalychiran and Chungurchatchiran have shrunk by 5.7 square kilometers. The shrinking in glacier thickness and the reduction in flow of glacier waters have resulted in the formation of barriers that look like riegels; at the same time, barriers that formed by dead ice of the medial moraine disappeared. This situation induced the constant change of glacial flow direction and the breach of lakes. The prediction for this area gives forthcoming radical reforming of the water network because of disappearance of the medial moraine ridge and the joining of the right-hand side of the river Birdzhaly-Su to the merging point of the river Kara-Kaya-Su.С 1957 по 2010 г. ледники северо-восточного подножия Эльбруса значительно уменьшились в размерах. Площадь ледников Бирджалычиран и Чунгурчатчиран сократилась на 5,7 км2. В результате уменьшения толщины ледников и их отступания на путях стока ледниковых вод образовались преграды в виде ригелей и исчезли преграды, сложенные мёртвыми льдами срединных морен. Это стало причиной частых изменений направлений ледникового стока и прорывов озёр. Сделан прогноз предстоящей коренной перестройки гидрографической сети, связанной с исчезновением гряды срединной морены на водораздельном участке и присоединением правой составляющей р. Бирджалы-Су к бассейну р. Кара-Кая-Су

Glacial lake inventory and lake outburst potential in Uzbekistan

Climate change has been shown to increase the number of mountain lakes across various mountain ranges in the World. In Central Asia, and in particular on the territory of Uzbekistan, a detailed assessment of glacier lakes and their evolution over time is, however lacking. For this reason we created the first detailed inventory of mountain lakes of Uzbekistan based on recent (2002–2014) satellite observations using WorldView-2, SPOT5, and IKONOS imagery with a spatial resolution from 2 to 10 m. This record was complemented with data from field studies of the last 50 years. The previous data were mostly in the form of inventories of lakes, available in Soviet archives, and primarily included localized in-situ data. The inventory of mountain lakes presented here, by contrast, includes an overview of all lakes of the territory of Uzbekistan. Lakes were considered if they were located at altitudes above 1500 m and if lakes had an area exceeding 100 m2. As in other mountain regions of the World, the ongoing increase of air temperatures has led to an increase in lake number and area. Moreover, the frequency and overall number of lake outburst events have been on the rise as well. Therefore, we also present the first outburst assessment with an updated version of well-known approaches considering local climate features and event histories. As a result, out of the 242 lakes identified on the territory of Uzbekistan, 15% are considered prone to outburst, 10% of these lakes have been assigned low outburst potential and the remainder of the lakes have an average level of outburst potential. We conclude that the distribution of lakes by elevation shows a significant influence on lake area and hazard potential. No significant differences, by contrast, exist between the distribution of lake area, outburst potential, and lake location with respect to glaciers by regions