Process dynamics, real time monitoring and early warning at an imminent cliff fall (Hochvogel, Allgäu Alps)

Author(s):  
Johannes Leinauer ◽  
Benjamin Jacobs ◽  
Michael Krautblatter

<p>Costs for (re)installation and maintenance of protective structures are increasing while alpine hazards progressively threaten alpine communities, infrastructure and economics. With climatic changes, anticipation and clever early warning of rock slope failures based on the process dynamics become more and more important. The imminent rock slope failure at the Hochvogel summit (2592 m a.s.l., Allgäu Alps) offers a rare possibility to study a cliff fall at a high alpine carbonate peak during its preparation and until failure. In this real case scenario, we can develop and test an operative and effective early warning system.</p><p>The main cleft is two to six metres wide at the summit and at least 60 metres deep at the sides. Several lateral cracks are opening at faster pace and separate different instable blocks. 3D-UAV point clouds reveal a potentially failing mass of 260,000 m³ in six subunits. However, the pre-deformation is yet not pronounced enough to decide on the expected volume. Analysis of historical ortho- and aerial images yields an elongation of the main crack length from 10 to 35 m from 1960 until now. Discontinuous tape extensometer measurements show 35 cm opening of the main cleft between 2014 and 2020 with movement rates up to 1 cm/month. Since July 2018, automatic vibrating wire gauges deliver high-resolution data to an online server. In October 2019, we transferred the system into LoRa with data transmission every 10 min. Automatic warnings via SMS and email are triggered when crossing specific thresholds.</p><p>Here we demonstrate long-term process dynamics and 2-years of high-resolution data of a preparing alpine rock slope failure. Corresponding geodetic, photogrammetric, seismic and gravimetric measurements complete the comprehensive measurement design at the Hochvogel. This will help to decipher anticipative signals of initiating alpine rock slope failures and improve future event predictions.</p>

2020 ◽  
Author(s):  
Andreas Linsbauer ◽  
Elias Hodel ◽  
Matthias Huss ◽  
Andreas Bauder ◽  
Mauro Fischer ◽  
...  

<p>A glacier inventory describes the extent of all glaciers at a given point in time and in periods of rapid glacier change a frequent update is needed. The Swiss Glacier Inventory 2010 (SGI2010) is the last official inventory for Switzerland and was derived by manual digitization from high-resolution (25 cm) aerial orthophotographs from swisstopo (Federal Office of Topography). To regularly produce a revised inventory, based on the high-quality aerial images from swisstopo acquired at a three-year interval, the workload cannot be covered by GLAMOS (Glacier Monitoring Switzerland, www.glamos.ch) on its own. As part of the development of the new topographic landscape model of Switzerland (swissTLM<sup>3D</sup>), swisstopo introduced – based on requirements defined by GLAMOS – the object class “glaciers”. This secures that Swiss glaciers are recurrently mapped based on high-resolution data on a long term. Swiss Glacier Inventories can therefore be derived by GLAMOS from the TLM object class “glaciers”.</p><p>The SGI2020 is the first glacier inventory produced by GLAMOS based on the new workflow and stands out with an unprecedented level of detail regarding glacier mapping. As the glacier-excerpt from the swisstopo TLM is a landcover dataset, produced according to guidelines for topographical purpose, it does not fit all glaciological requirements. Here, we present the necessary steps and adjustments to derive a new glacier inventory for the period 2013-2018 that fits all glaciological criteria. Furthermore, we compare the resulting dataset with former SGI’s and pin down the major changes and differences emerging from different methodologies used. We particularly emphasize on problematic definitions of glacier boundaries related to snow coverage and/or supraglacial debris and provide updated results for glacier area changes in the Swiss Alps over the last decades.</p>


Author(s):  
I. V. Florinsky ◽  
T. N. Skrypitsyna ◽  
D. P. Bliakharskii ◽  
O. T. Ishalina ◽  
A. S. Kiseleva

Abstract. Glaciated areas are important targets for interdisciplinary research. In the last quarter of the 20th century, there has been a significant shift in glacier observation approaches from direct fieldwork to remote sensing. Over the past 15 years, unmanned aerial systems have been increasingly used for this purpose. In this article, we briefly describe a newly launched Russian–Chinese project aimed at developing a theory and methodology for digital modeling and analysis of the glacier microtopography using very high resolution data from unmanned aerial surveys. We argue the relevance of the study and review key publications on the application of digital terrain modeling and geomorphometry in glaciology. Next, we discuss the aim of the project and tasks performed by the Russian side, as well as materials and methods used in the study. As initial data, we use multi-temporal, digital aerial images of very high resolution (5 cm) collected by the unmanned aerial survey of the ice sheet and glaciers near the Larsemann Hills, East Antarctic. Finally, we present some examples for geomorphometric analysis of glacier microtopography including snow/ice features of eolian origin.


2009 ◽  
Vol 474 (1-2) ◽  
pp. 271-284 ◽  
Author(s):  
L. Tosi ◽  
P. Teatini ◽  
L. Carbognin ◽  
G. Brancolini

2021 ◽  
Author(s):  
Kyalo Richard ◽  
Elfatih M. Abdel-Rahman ◽  
Sevgan Subramanian ◽  
Johnson O. Nyasani ◽  
Michael Thiel ◽  
...  

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