Озёра у ледника Малый Азау на Эльбрусе: динамика и прорывы

The lake dynamics and the current state of them were analyzed on the basis of interpretation of aerial and satellite images of different years together with results of field surveys. Areas of six lakes existing in different years near the Maliy Azau Glacier had been determined. On August 22, 2011, the maximum area of one of the lakes was equal to 25.5 thousand m2. The first outburst was caused by the landslide deformations of the moraine massif forming a part of the lake basin, while the second one was a result of degradation of the lake ice dam and the water overflow on top of it. The present‑day lake dams (terminal‑moraine ramparts and medial moraine ridges) are the result of the Maliy Azau Glacier advance in 1990s. The revealed feature of the lake dynamics on the mountain Elbrus was a drop of the water level and corresponding decrease of the lake areas in winter that was related to existence of the groundwater runoff into fractured volcanic rocks. At present, moraine dams of lakes and areas of the surface water runoff from the lakes are in stable condition due to which there is no threat of a lake outburst. However, the potential threat of outburst still remains because of high seismicity and possible volcanic activity in this region.На основе дешифрирования аэрофотоснимков и космических снимков приводятся данные о количестве и динамике озёр у ледника Малый Азау за 1957–2015 гг. Наибольшая площадь озера (25,5 тыс. м2) зафиксирована на космоснимке 22.08.2011 г. незадолго до прорыва. Прорывы озёр происходили в 1978 и 2011 гг. и имели разные причины. Первый прорыв связан с оползневыми деформациями моренного массива, слагающего часть озёрной котловины, второй – с деградацией ледяной плотины озера и переливом воды поверх неё. Установлен также факт значительного падения уровня воды в озёрах в зимний период

Soil patterns as a factor of crop heterogeneity

This paper examines the relationship between the heterogeneity of different crops in the Tula region of the Russian Federation based on vegetation observations during the period 2015-2020 with the mapping units of a large (scale 1:10,000) soil map. NDVI values calculated from Sentinel-2 satellite data were used as a measure of crop heterogeneit

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

История ледника Донгуз-Орун по биоиндикационным, историческим, картографическим источникам и данным дистанционного зондирования

On the basis of dendrochronological, lichenometric and historical data with the use of Earth remote sensing materials, the evolution of the Donguz-Orun Glacier has been reconstructed over the past centuries. In this work we used aerial photographs of 1957, 1965, 1981, 1987, satellite image of 2009, as well as descriptions, photographs, maps and plans of the glacier of the 19th and 20th centuries, data of instrumental measurements of the glacier end position in the second half of the 20th – early 21st centuries, dendrochronological dating of pine on the front part of the valley, and juniper to date coastal moraines, and the results of lichenometry studies. It has been established that the Donguz-Orun Glacier in the past had several clearly marked advances about 100, 200 and more than 350 years ago, which are expressed in relief in the form of uneven-aged coastal moraines. Despite the fact that the Donguz-Orun Glacier differs from many mountain-valley glaciers of the Caucasus primarily by its predominantly avalanche feeding and a moraine cover, almost entirely covering its surface, the main periods of its advances are consistent with the known large fluctuations of mountain glaciers during the Little Ice Age in the early 20th, early 19th, and, probably, in the middle of the 17th century. However, unlike most other Caucasian glaciers, the Donguz-Orun Glacier advanced in the 1970s–2000s. Te scale of its degradation from the end of the 19th to the beginning of the 21st century is also uncharacteristic for the Caucasus: the reduction in the length for longer than a century period is only about 100 m.Проведены исследования изменений долинного ледника Донгуз-Орун за последние три с половиной столетия. Границы положения конца ледника определялись по аэрофото- и космическим снимкам, а также по историческим описаниям, фотографиям, картам и планам ледника, дендрохронологическим датировкам по сосне и можжевельнику и результатам лихенометрических исследований. Установлено, что ледник Донгуз-Орун в прошлом имел несколько чётко выраженных наступаний около 100, 200 и более 350 лет назад, следы которых находят отражение в рельефе в виде разновозрастных береговых морен

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

A massive rock and ice avalanche caused the 2021 disaster at Chamoli, Indian Himalaya

On 7 Feb 2021, a catastrophic mass flow descended the Ronti Gad, Rishiganga, and Dhauliganga valleys in Chamoli, Uttarakhand, India, causing widespread devastation and severely damaging two hydropower projects. Over 200 people were killed or are missing. Our analysis of satellite imagery, seismic records, numerical model results, and eyewitness videos reveals that ~27x106 m3 of rock and glacier ice collapsed from the steep north face of Ronti Peak. The rock and ice avalanche rapidly transformed into an extraordinarily large and mobile debris flow that transported boulders >20 m in diameter, and scoured the valley walls up to 220 m above the valley floor. The intersection of the hazard cascade with downvalley infrastructure resulted in a disaster, which highlights key questions about adequate monitoring and sustainable development in the Himalaya as well as other remote, high-mountain environments

Lakes near the glacier Maliy Azau on the Elbrus (Central Caucasus): dynamics and outbursts

The lake dynamics and the current state of them were analyzed on the basis of interpretation of aerial and satellite images of different years together with results of field surveys. Areas of six lakes existing in different years near the Maliy Azau Glacier had been determined. On August 22, 2011, the maximum area of one of the lakes was equal to 25.5 thousand m2. The first outburst was caused by the landslide deformations of the moraine massif forming a part of the lake basin, while the second one was a result of degradation of the lake ice dam and the water overflow on top of it. The present‑day lake dams (terminal‑moraine ramparts and medial moraine ridges) are the result of the Maliy Azau Glacier advance in 1990s. The revealed feature of the lake dynamics on the mountain Elbrus was a drop of the water level and corresponding decrease of the lake areas in winter that was related to existence of the groundwater runoff into fractured volcanic rocks. At present, moraine dams of lakes and areas of the surface water runoff from the lakes are in stable condition due to which there is no threat of a lake outburst. However, the potential threat of outburst still remains because of high seismicity and possible volcanic activity in this region

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»