Susceptibility of glacial lakes to avalanche and rockfall in the Hindu-Kush-Himalaya

2021 ◽  
Author(s):  
Saket Dubey ◽  
Manish Goyal ◽  
Ashim Sattar ◽  
Umesh Haritashya
Keyword(s):  
Mass Movement ◽  
Major Axis ◽  
Glacial Lakes ◽  
Hazard Management ◽  
Runout Distance ◽  
Outburst Floods ◽  
Hindu Kush ◽  
Run Up ◽  
The Stability ◽  
Critical Regions

<p>The Hindu-Kush-Himalayan region is home to numerous glacial lakes. Some of these lakes could fail and produce hazardous Glacial Lake Outburst Floods (GLOF). GLOFs are primarily triggered by an avalanche or a rockfall entering the lake that generates an overtopping displacement waves. In the present study, we investigate the susceptibility of all lakes present in the Hindu-Kush-Karakorum (HKH) region (Randolph Glacier inventory region 14 and 15) to the dynamic mass movement (avalanche and rockfall). Avalanche and rockfall trajectories are developed considering various depths and “Minimum Look-Up Angle” (MLUA: a term used to define the avalanche runout distance). These trajectories are also validated against the results obtained from the Rapid Mass Movement Simulation (RAMMS) model. The mass movement of avalanche or rockfall along the major axis may enhance the wave run-up leading to a higher impact on the damming structure. Therefore, each susceptible lake is critically assessed for the angle of intrusion of a mass movement. The stability of the glacial lakes was also evaluated using the steep lake front area method to understand the associated hazard. Obtained results suggest that out of 3725 glacial lakes, 239 are susceptible to an avalanche when the mean avalanche depth is considered 50 m, and only 43 if the assumed mean avalanche depth is reduced to 10 m. Furthermore, the rockfall trajectories suggest that 343 lakes are susceptible to rockfall while considering MLUA of 17˚, which falls to 217 when MLUA is increased to 23˚. Overall, glacial lakes in the Central Himalayas were more susceptible to mass movement than the Karakoram, Western and Eastern Himalayas. We hope that our work will enable stakeholders to make a well-informed decision for hazard management in the Hindu-Kush-Himalayas. In addition to this, developed avalanche and rockfall trajectories will also help identify critical regions and hazard susceptibility structures.</p>

scholarly journals Future glacial lakes in High Mountain Asia: an inventory and assessment of hazard potential from surrounding slopes

2021 ◽  
pp. 1-18
Author(s):  
Wilhelm Furian ◽  
David Loibl ◽  
Christoph Schneider
Keyword(s):  
Mass Movement ◽  
High Mountain ◽  
Lake Area ◽  
Glacial Lakes ◽  
Mountain Areas ◽  
Glacial Retreat ◽  
Proglacial Lakes ◽  
Outburst Floods ◽  
Glacial Lake Outburst Floods ◽  
Triggering Events

Abstract Bedrock overdeepenings exposed by continued glacial retreat can store precipitation and meltwater, potentially leading to the formation of new proglacial lakes. These lakes may pose threats of glacial lake outburst floods (GLOFs) in high mountain areas, particularly if new lakes form in geomorphological setups prone to triggering events such as landslides or moraine collapses. We present the first complete inventory for future glacial lakes in High Mountain Asia by computing the subglacial bedrock for ~100 000 glaciers and estimating overdeepening area, volume and impact hazard for the larger potential lakes. We detect 25 285 overdeepenings larger than 104 m2 with a volume of 99.1 ± 28.6 km3 covering an area of 2683 ± 773.8 km2. For the 2700 overdeepenings larger than 105 m2, we assess the lake predisposition for mass-movement impacts that could trigger a GLOF by estimating the hazard of material detaching from surrounding slopes. Our findings indicate a shift in lake area, volume and GLOF hazard from the southwestern Himalayan region toward the Karakoram. The results of this study can be used for anticipating emerging threats and potentials connected to glacial lakes and as a basis for further studies at suspected GLOF hazard hotspots.

scholarly journals Simulation and Assessment of Future Glacial Lake Outburst Floods in the Poiqu River Basin, Central Himalayas

Water ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1376
Author(s):  
Taigang Zhang ◽  
Weicai Wang ◽  
Tanguang Gao ◽  
Baosheng An
Keyword(s):  
River Basin ◽  
Hazard Assessment ◽  
Glacial Lake ◽  
High Mountain ◽  
Glacial Lakes ◽  
Central Himalayas ◽  
Outburst Floods ◽  
Glacial Lake Outburst Floods ◽  
Social And Economic Development ◽  
Glacial Lake Outburst Flood

A glacial lake outburst flood (GLOF) is a typical glacier-related hazard in high mountain regions. In recent decades, glacial lakes in the Himalayas have expanded rapidly due to climate warming and glacial retreat. Some of these lakes are unstable, and may suddenly burst under different triggering factors, thus draining large amounts of water and impacting downstream social and economic development. Glacial lakes in the Poiqu River basin, Central Himalayas, have attracted great attention since GLOFs originating there could have a transboundary impact on both China and Nepal, as occurred during the Cirenmaco GLOF in 1981 and the Gongbatongshaco GLOF in 2016. Based on previous studies of this basin, we selected seven very high-risk moraine-dammed lakes (Gangxico, Galongco, Jialongco, Cirenmaco, Taraco, Beihu, and Cawuqudenco) to simulate GLOF propagation at different drainage percentage scenarios (i.e., 25%, 50%, 75%, and 100%), and to conduct hazard assessment. The results show that, when any glacial lake is drained completely or partly, most of the floods will enter Nepal after raging in China, and will continue to cause damage. In summary, 57.5 km of roads, 754 buildings, 3.3 km2 of farmland, and 25 bridges are at risk of damage due to GLOFs. The potentially inundated area within the Chinese part of the Poiqu River basin exceeds 45 km2. Due to the destructive impacts of GLOFs on downstream areas, appropriate and effective measures should be implemented to adapt to GLOF risk. We finally present a paradigm for conducting hazard assessment and risk management. It uses only freely available data and thus is easy to apply.

scholarly journals Glacial lake change risk and management on the Chinese Nyainqentanglha in the past 40 years

2016 ◽  
Author(s):  
Wang Shijin
Keyword(s):  
Lake Area ◽  
Glacial Lakes ◽  
Analytic Hierarchy ◽  
Adaptation Capacity ◽  
Comprehensive Method ◽  
Outburst Floods ◽  
Integrated Risk ◽  
Lake Change ◽  
Hierarchy Process ◽  
County Scale

Abstract. The paper analyzed synthetically spatial distribution and evolution status of moraine-dammed lakes in the Nyainqentanglha Mountain, revealed risk degree of county-based potential dangerous glacial lakes (PDGLs) outburst floods disaster by combining PDGLs outburst hazard, regional exposure, vulnerability of exposed elements and adaptation capability and using the Analytic Hierarchy Process and Weighted Comprehensive Method. The results indicate that 132 moraine-dammed lakes (> 0.02 km2) with a total area of 38.235 km2 were detected in the Nyainqentanglha in the 2010s, the lake number decreased only by 5 %, whereas total lake area expanded by 22.72 %, in which 54 lakes with a total area of 17.53 km2 are identified as PDGLs and total area increased by 144.31 %, higher significantly than 4.06 % of non-PDGLs. The zones at very high and high integrated risk of glacial lakes outburst floods (GLOFs) disaster are concentrated in the eastern Nyainqentanglha, whereas low and very low integrated risk zones are located mainly in the western Nyainqentanglha. On the county scale, Nagque and Nyingchi have the lowest hazard risk, Banbar has the highest hazard and vulnerability risk, Sog and Lhorong have the highest exposure risk. In contrast, Biru and Jiali have the highest vulnerability risk, while Gongbo'gyamda and Damxung have lowest adaptation capacity. The regionalization results for GLOF disaster risk in the study are consistent with the distribution of historical disaster sites across the Nyainqentanglha.

Simple Leg Placement Strategy for a One Legged Running Model

2012 ◽  
Author(s):  
Timothy Sullivan ◽  
Justin Seipel
Keyword(s):  
Stance Phase ◽  
Energy State ◽  
Center Of Mass ◽  
Mass Movement ◽  
Legged Locomotion ◽  
Energy Conserving ◽  
Lower Torque ◽  
The Stability ◽  
Time Required ◽  
Torque Values

The Spring Loaded Inverted Pendulum (SLIP) model was developed to describe center of mass movement patterns observed in animals, using only a springy leg and a point mass. However, SLIP is energy conserving and does not accurately represent any biological or robotic system. Still, this model is often used as a foundation for the investigation of improved legged locomotion models. One such model called Torque Damped SLIP (TD-SLIP) utilizes two additional parameters, a time dependent torque and dampening to drastically increase the stability. Forced Damped SLIP (FD-SLIP), a predecessor of TD-SLIP, has shown that this model can be further simplified by using a constant torque, instead of a time varying torque, while still maintaining stability. Using FD-SLIP as a base, this paper explores a leg placement strategy using a simple PI controller. The controller takes advantage of the fact that the energy state of FD-SLIP is symmetric entering and leaving the stance phase during steady state conditions. During the flight phase, the touch down leg angle is adjusted so that the energy dissipation due to dampening, during the stance phase, compensates for any imbalance of energy. This controller approximately doubles the region of stability when subjected to velocity perturbations at touchdown, enables the model to operate at considerably lower torque values, and drastically reduces the time required to recover from a perturbation, while using less energy. Finally, the leg placement strategy used effectively imitates the natural human response to velocity perturbations while running.

scholarly journals III. Researches in physical astronomy

1831 ◽  
Vol 121 ◽  
pp. 17-66
Keyword(s):  
Angular Velocity ◽  
Major Axis ◽  
The Body ◽  
Fixed Plane ◽  
Resisting Medium ◽  
Axis Of Rotation ◽  
Geographical Latitude ◽  
The Mean ◽  
The Stability ◽  
Revolving Body

In last April I had the honour of presenting to the Society a paper containing expressions for the variations of the elliptic constants in the theory of the motions of the planets. The stability of the solar system is established by means of these expressions, if the planets move in a space absolutely devoid of any resistance*, for it results from their form that however far the ap­proximation be carried, the eccentricity, the major axis, and the tangent of the inclination of the orbit to a fixed plane, contain only periodic inequalities, each of the three other constants, namely, the longitude of the node, the longitude of the perihelion, and the longitude of the epoch, contains a term which varies with the time, and hence the line of apsides and the line of nodes revolve continually in space. The stability of the system may therefore be inferred, which would not be the case if the eccentricity, the major axis, or the tangent of the inclination of the orbit to a fixed plane contained a term varying with the time, however slowly. The problem of the precession of the equinoxes admits of a similar solution; of the six constants which determine the position of the revolving body, and the axis of instantaneous rotation at any moment, three have only periodic inequalities, while each of the other three has a term which varies with the time. From the manner in which these constants enter into the results, the equilibrium of the system may be inferred to be stable, as in the former case. Of the constants in the latter problem, the mean angular velocity of rotation may be considered analogous to the mean motion of a planet, or its major axis ; the geographical longitude, and the cosine of the geographical latitude of the pole of the axis of instantaneous rotation, to the longitude of the perihelion and the eccentricity; the longitude of the first point of Aries and the obliquity of the ecliptic, to the longitude of the node and the inclination of the orbit to a fixed plane; and the longitude of a given line in the body revolving, passing through its centre of gravity, to the longitude of the epoch. By the stability of the system I mean that the pole of the axis of rotation has always nearly the same geographical latitude, and that the angular velocity of rotation, and the obliquity of the ecliptic vary within small limits, and periodically. These questions are considered in the paper I now have the honour of submitting to the Society. It remains to investigate the effect which is produced by the action of a resisting medium; in this case the latitude of the pole of the axis of rotation, the obliquity of the ecliptic, and the angular velocity of rotation might vary considerably, although slowly, and the climates undergo a con­siderable change.

The Status of Glacial Lakes in the Hindu Kush Himalaya - ICIMOD Research Report 2018/1

2018 ◽  
Author(s):  
S. B. Maharjan ◽  
P. K. Mool ◽  
W. Lizong ◽  
G. Xiao ◽  
F. Shrestha ◽  
...  
Keyword(s):  
Research Report ◽  
Glacial Lakes ◽  
Hindu Kush ◽  
The Status

Governing by Rules and Ruling by Numbers in the Eurozone Crisis

2020 ◽  
pp. 87-116
Author(s):  
Vivien A. Schmidt
Keyword(s):  
European Monetary Union ◽  
Political Legitimacy ◽  
Monetary Integration ◽  
Banking Union ◽  
Eurozone Crisis ◽  
Policy Responses ◽  
Growth Pact ◽  
History Of ◽  
Run Up ◽  
The Stability

Chapter 4 provides an overview of the Eurozone crisis, to serve as a background for the subsequent four chapters which discuss in turn each of the four EU actors’ particular pathways to legitimacy, including their sources of power and grounds for throughput legitimacy, along with the Janus-faced public perceptions of their Eurozone governance. The chapter begins with a brief review of the history of European Monetary Union (EMU), describing the trials and tribulations in the run-up to the Maastricht Treaty and member states’ very different ideas and discourse related to monetary integration, as illustrated by the differences in German, French, and Italian views. It then considers what happened at the time of the introduction of the single currency. The chapter follows with the initial responses to the Eurozone crisis during its fast-burning phase, characterized by a doubling down on the rules of the Stability and Growth Pact. It elaborates on the trials and tribulations at the inception of the crisis, on EU actors’ initial actions and reactions, and on institutional innovations such as banking union. It also provides further details on legislation and treaty agreements, as well as on the ideas underpinning the policy responses. The chapter ends by considering the benefits and drawbacks of EU actors’ subsequent reinterpretation of the rules by stealth during the Eurozone crisis’ slow-burning phase, arguing that although rules reinterpretation may have improved policy responses (output), not admitting this raised questions of accountability and transparency (throughput), while failing to address problems of political legitimacy (input).

scholarly journals Glacial Lakes Outburst Floods (GLOFs) modelling of Thulagi and Lower Barun Glacial Lakes of Nepalese Himalaya

2020 ◽  
Vol 7 ◽  
pp. 100106 ◽  
Author(s):  
Sunwi Maskey ◽  
Rijan Bhakta Kayastha ◽  
Rakesh Kayastha
Keyword(s):  
Glacial Lakes ◽  
Outburst Floods

A Discussion on valley slopes and cliffs in southern England: morphology, mechanics and Quaternary history - The development of an abandoned cliff in London Clay at Hadleigh, Essex

1976 ◽  
Vol 283 (1315) ◽  
pp. 557-604 ◽  
Keyword(s):  
19Th Century ◽  
Pore Water ◽  
Mass Movement ◽  
Late Glacial ◽  
Late 19Th Century ◽  
Accumulation Zone ◽  
Capillary Zone ◽  
London Clay ◽  
The Times ◽  
The Stability

Hadleigh Cliff forms part of a line of abandoned London Clay slopes, rising to a height of generally + 40 m o.d. or more, which extends westwards from Southend-on- Sea. The cliff, with its toe level originally at about —19 m o.d., was formed by strong fluvial erosion in the Middle and Late Devensian. By the latter part of the Late Devensian erosion had virtually ceased and since then the cliff has degraded in an episodic manner, largely in response to climatic changes. Four main stages of degradation, with intermediate periods of relative stability, have been recognized and dated, as follows: (1) Late-glacial, periglacial mudsliding, associated with a toe level of —19 m o.d. (2) Early Atlantic, temperate mudsliding, associated with a toe level which was rising with the continuing Flandrian aggradation, but lay on average at about —9m o.d. (3) Early Sub-Atlantic, temperate mudsliding, taking place to the present toe level of about + 3 m o.d. (4) A late 19th century, moderately deep-seated landslide in the crest of the slope, possibly caused in part by human interference. The times at which the first three of these stages of degradation occurred are believed to represent periods of generally increased mass movement activity in much of Britain and Europe. The present morphology of Hadleigh Cliff comprises a straight 20 scarp at the crest, an irregular and actively unstable 11° degradation zone, fronted by a smoother, quasi-stable accumulation zone inclined at about 8°. From a knowledge of the volumes and dates of the various colluvial units mantling the slope, reconstructions of earlier positions of the cliff profile are made. These indicate that during the last 10 000 years the inclination of the combined degradation zone and crest scarp has declined from about 19° to 13°, while that of the accumulation zone has remained relatively constant. The accompanying recession of the cliff crest has been approximately 50 m. From the pattern and dating of the various stages of colluviation, which increase both in age and in degree of fabric breakdown from crest to toe of the slope, it is clear that the cliff is degrading from the top. This is also reflected in the fact that the zone of weathered, in situ London Clay beneath the colluvium diminishes in thickness, in general, from bottom to top of the slope and is entirely absent beneath the late 19th century landslide. In an average year the potential evaporation at Hadleigh exceeds the rainfall. As a result soil moisture deficits are unusually high and appreciable pore-water tensions in the capillary zone probably exist even at times of maximum seasonal piezometric levels. Account is taken of these in the stability analyses that are carried out, which indicate that the accumulation zone has a factor of safety of around 1.05 in com­ parison with the value of unity obtaining in the currently unstable degradation zone. A comparison between the values of (pT indicated by the back analyses and those measured on the Hadleigh colluvium in ring shear shows the latter to be appreciably the lower: the discrepancy is reduced if the effects of pore-water tensions in the capillary zone are allowed for.

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