A Rockfall inventory: Ötztal Alps, Tyrol, Austria

2020 ◽  
Author(s):  
Bettina Knoflach ◽  
Hannah Tussetschläger ◽  
Rudolf Sailer ◽  
Gertraud Meißl ◽  
Johann Stötter
Keyword(s):  
Regional Scale ◽  
Empirical Models ◽  
High Mountain ◽  
Systematic Observation ◽  
Runout Distance ◽  
Digital Elevation ◽  
Maximum Range ◽  
Close Relationship ◽  
Elevation Model ◽  
Insight Into

<p>Climate change has serious implications for the cryosphere and a close relationship between the instability of rock faces and the changes in high mountain permafrost is suspected. Although, the number of rockfall events in Alpine areas is increasing, detailed analyses of the frequency and runout distances in high altitudes are rare. This study gives an insight into the rockfall activity in the Ötztal Alps in Tyrol, Austria. A systematic observation utilizing bi-temporal ALS-DTMs in combination with orthoimages revealed a total of 93 rockfalls over an area of 637 km² in the period from 2006 to 2010. Since more than 90 % of the rockfall release areas were mapped in potential permafrost areas, a correlation between rockfall activity and climatically driven degradation of permafrost in bedrock is very likely. 18 rockfall events, ranging in volume from 69 to 8420 m³, were suitable for runout assessments. To estimate the maximum range of future rockfalls with empirical models, values of 30 ° (Fahrböschung) and 26 ° (minimum shadow angle) can be proposed for risk assessment at a regional scale (1:25,000 – 1:100,000). Rockfalls occurring on snow or ice may also go below these values.</p><p><strong>Keywords</strong>: Rockfall, Permafrost, digital elevation model; runout distance, Fahrböschung, minimum shadow angle, Ötztal Alps</p>

2020 hurricane impact assessment for the northern Gulf of Mexico: Hurricane Sally and Hurricane Zeta

Shore & Beach ◽  
2021 ◽  
pp. 56-64
Author(s):  
S. McGill ◽  
C. Sylvester ◽  
L. Dunkin ◽  
E. Eisemann ◽  
J. Wozencraft
Keyword(s):  
Change Detection ◽  
Gulf Coast ◽  
Regional Scale ◽  
Shoreline Change ◽  
Airborne Lidar ◽  
Digital Elevation ◽  
The Status ◽  
Northern Gulf Coast ◽  
Elevation Model ◽  
Beach Volume

Regional-scale shoreline and beach volume changes are quantified using the Joint Airborne Lidar Bathymetry Technical Center of Expertise’s digital elevation model products in a change detection framework following the passage of the two landfalling hurricanes, Hurricanes Sally and Zeta, along the northern Gulf Coast in late fall 2020. Results derived from this work include elevation change raster products and a standard set of beach volume and shoreline change metrics. The rapid turn-around and delivery of data products to include volume and shoreline change assessments provide valuable information about the status of the coastline and identification of areas of significant erosion or other impacts, such as breaching near Perdido Key, FL, from Hurricane Sally’s impact. These advanced change detection products help inform sediment budget development and support decisions related to regional sediment management and coastal storm risk management.

scholarly journals Avalanche situation in Turkey and back calculation of selected events

2014 ◽  
Vol 14 (5) ◽  
pp. 1145-1154 ◽  
Author(s):  
A. Aydin ◽  
Y. Bühler ◽  
M. Christen ◽  
I. Gürer
Keyword(s):  
Simulation Software ◽  
High Mountain ◽  
Identification Algorithm ◽  
Black Sea Region ◽  
Mountain Ranges ◽  
Digital Elevation ◽  
Back Calculation ◽  
Elevation Model ◽  
Very High ◽  
Rapid Mass

Abstract. In Turkey, an average of 24 people die in snow avalanches every year, mainly in the eastern part of Anatolia and in the eastern Black Sea region, where high-mountain ranges are close to the sea. The proportion of people killed in buildings is very high (87%), especially in comparison to other European countries and North America. In this paper we discuss avalanche occurrence, the climatic situation and historical avalanche events in Turkey; in addition, we identify bottlenecks and suggest solutions to tackle avalanche problems. Furthermore, we have applied the numerical avalanche simulation software RAMMS (rapid mass movements simulation) combined with a (digital elevation model) DEM-based potential release zone identification algorithm to analyze the catastrophic avalanche events in the villages of Üzengili (Bayburt province) in 1993 and Yaylaönü (Trabzon province) in 1981. The results demonstrate the value of such an approach for regions with poor avalanche databases, enabling the calculation of different scenarios and the estimation of run-out distances, impact pressure and flow height.

scholarly journals Distinguishing Glaciers between Surging and Advancing by Remote Sensing: A Case Study in the Eastern Karakoram

2020 ◽  
Vol 12 (14) ◽  
pp. 2297 ◽  
Author(s):  
Mingyang Lv ◽  
Huadong Guo ◽  
Jin Yan ◽  
Kunpeng Wu ◽  
Guang Liu ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Google Earth ◽  
High Mountain ◽  
Glacier Mass Balance ◽  
Visual Interpretation ◽  
Stable Mode ◽  
Optical Images ◽  
Digital Elevation ◽  
Glacier Surges ◽  
Elevation Model

The Karakoram has had an overall slight positive glacier mass balance since the end of 20th century, which is anomalous given that most other regions in High Mountain Asia have had negative changes. A large number of advancing, retreating, and surging glaciers are heterogeneously mixed in the Karakoram increasing the difficulties and inaccuracies to identify glacier surges. We found two adjacent glaciers in the eastern Karakoram behaving differently from 1995 to 2019: one was surging and the other was advancing. In order to figure out the differences existing between them and the potential controls on surges in this region, we collected satellite images from Landsat series, ASTER, and Google Earth, along with two sets of digital elevation model. Utilizing visual interpretation, feature tracking of optical images, and differencing between digital elevation models, three major differences were observed: (1) the evolution profiles of the terminus positions occupied different change patterns; (2) the surging glacier experienced a dramatic fluctuation in the surface velocities during and after the event, while the advancing glacier flowed in a stable mode; and (3) surface elevation of the surging glacier decreased in the reservoir and increased in the receiving zone. However, the advancing glacier only had an obvious elevation increase over its terminus part. These differences can be regarded as standards for surge identification in mountain ranges. After combining the differences with regional meteorological conditions, we suggested that changes of thermal and hydrological conditions could play a role in the surge occurrence, in addition, geomorphological characteristics and increasing warming climate might also be part of it. This research strongly contributes to the literatures of glacial motion and glacier mass change in the eastern Karakoram through remote sensing.

scholarly journals Reconstructing the Dynamic Processes of the Taimali Landslide in Taiwan Using the Waveform Inversion Method

2020 ◽  
Vol 10 (17) ◽  
pp. 5872
Author(s):  
Guan-Wei Lin ◽  
Ching Hung
Keyword(s):  
Waveform Inversion ◽  
Time Function ◽  
Dynamic Processes ◽  
Inversion Method ◽  
Runout Distance ◽  
Digital Elevation ◽  
Single Station ◽  
Force Time ◽  
Elevation Model ◽  
Inversion Techniques

As a landslide occurs, seismic signals generated by the mass sliding on the slope can be recorded by seismometers nearby. Using waveform inversion techniques, we can explore the dynamic processes (e.g., sliding direction, velocity, and runout distance) of a landslide with the inverted force–time function. In this study, the point force history (PFH) inversion method was applied to the Taimali landslide in Taiwan, which was triggered by a heavy rainstorm in 2009. The inverted force–time function for the landslide revealed the complicated dynamic processes. The time series of velocity indicated three different sliding directions during the landslide. Hence, three propagating stages of the Taimali landslide were determined and were consistent with an investigation using remote sensing images and a digital elevation model of the landslide. In addition, the PFH inversion was implemented using high-quality single-station records and maintained good performance compared with the inversion by multistation records.

scholarly journals UAV-Derived Himalayan Topography: Hazard Assessments and Comparison with Global DEM Products

Drones ◽  
2019 ◽  
Vol 3 (1) ◽  
pp. 18 ◽  
Author(s):  
C. Watson ◽  
Jeffrey Kargel ◽  
Babulal Tiruwa
Keyword(s):  
Mass Movement ◽  
High Mountain ◽  
Lake Area ◽  
Digital Elevation ◽  
2015 Gorkha Earthquake ◽  
Order Of Magnitude ◽  
Hazard Assessments ◽  
Elevation Model ◽  
Terrain Elevation ◽  
Fine Resolution

Topography derived using human-portable unmanned aerial vehicles (UAVs) and structure from motion photogrammetry offers an order of magnitude improvement in spatial resolution and uncertainty over small survey extents, compared to global digital elevation model (DEM) products, which are often the only available choice of DEMs in the high-mountain Himalaya. Access to fine-resolution topography in the high mountain Himalaya is essential to assess where flood and landslide events present a risk to populations and infrastructure. In this study, we compare the topography of UAV-derived DEMs, three open-access global DEM products, and the 8 m High Mountain Asia (HMA) DEMs (released in December 2017) and assess their suitability for landslide- and flood-related hazard assessments. We observed close similarity between UAV and HMA DEMs when comparing terrain elevation, river channel delineation, landside volume, and landslide-dammed lake area and volume. We demonstrate the use of fine-resolution topography in a flood-modelling scenario relating to landslide-dammed lakes that formed on the Marsyangdi River following the 2015 Gorkha earthquake. We outline a workflow for using UAVs in hazard assessments and disaster situations to generate fine-resolution topography and facilitate real-time decision-making capabilities, such as assessing landslide-dammed lakes, mass movement volumes, and flood risk.

A new high-resolution bathymetry model for the Terre Adélie and George V continental margin, East Antarctica

2010 ◽  
Vol 23 (1) ◽  
pp. 95-103 ◽  
Author(s):  
Robin J. Beaman ◽  
Philip E. O’Brien ◽  
Alexandra L. Post ◽  
Laura De Santis
Keyword(s):  
High Resolution ◽  
Digital Elevation Model ◽  
Continental Margin ◽  
Regional Scale ◽  
Spatial Relationship ◽  
East Antarctica ◽  
Digital Elevation ◽  
Terre Adélie ◽  
Elevation Model ◽  
High Resolution Bathymetry

AbstractThe Collaborative East Antarctic Marine Census (CEAMARC) surveys to the Terre Adélie and George V continental margin highlight the requirement for a revised high-resolution bathymetry model that can be used as a spatial tool for improving information on the physical environment of the region. We have combined shiptrack singlebeam and multibeam bathymetry, coastline data, and land and ice sheet topographic data to develop a new regional-scale bathymetry grid, called GVdem (short for George V digital elevation model). The GVdem grid spans an area between 138–148°E and 63–69°S, with a cell pixel size of 0.001-arcdegree (c. 100 m). The revised digital elevation model is a large improvement over previously available regional-scale grids from the area, and highlights seabed physiographic detail not formerly observed in this part of East Antarctica. In particular, the extent and complexity of the rugged inner-shelf valleys are revealed, and their spatial relationship with large shelf basins and adjacent flat-topped banks. The new grid also reveals further insight into the spatial distribution of the submarine canyons found on the continental slope.

scholarly journals A consistent glacier inventory for Karakoram and Pamir derived from Landsat data: distribution of debris cover and mapping challenges

2018 ◽  
Vol 10 (4) ◽  
pp. 1807-1827 ◽  
Author(s):  
Nico Mölg ◽  
Tobias Bolch ◽  
Philipp Rastner ◽  
Tazio Strozzi ◽  
Frank Paul
Keyword(s):  
High Mountain ◽  
Glacier Inventory ◽  
Temperature And Precipitation ◽  
Abstract Knowledge ◽  
Run Off ◽  
Digital Elevation ◽  
Debris Cover ◽  
Specific Calculations ◽  
Elevation Model ◽  
Year 2000

Abstract. Knowledge about the coverage and characteristics of glaciers in High Mountain Asia (HMA) is still incomplete and heterogeneous. However, several applications, such as modelling of past or future glacier development, run-off, or glacier volume, rely on the existence and accessibility of complete datasets. In particular, precise outlines of glacier extent are required to spatially constrain glacier-specific calculations such as length, area, and volume changes or flow velocities. As a contribution to the Randolph Glacier Inventory (RGI) and the Global Land Ice Measurements from Space (GLIMS) glacier database, we have produced a homogeneous inventory of the Pamir and the Karakoram mountain ranges using 28 Landsat TM and ETM+ scenes acquired around the year 2000. We applied a standardized method of automated digital glacier mapping and manual correction using coherence images from the Advanced Land Observing Satellite 1 (ALOS-1) Phased Array type L-band Synthetic Aperture Radar 1 (PALSAR-1) as an additional source of information; we then (i) separated the glacier complexes into individual glaciers using drainage divides derived by watershed analysis from the ASTER global digital elevation model version 2 (GDEM2) and (ii) separately delineated all debris-covered areas. Assessment of uncertainties was performed for debris-covered and clean-ice glacier parts using the buffer method and independent multiple digitizing of three glaciers representing key challenges such as shadows and debris cover. Indeed, along with seasonal snow at high elevations, shadow and debris cover represent the largest uncertainties in our final dataset. In total, we mapped more than 27 800 glaciers >0.02 km2 covering an area of 35 520±1948 km2 and an elevation range from 2260 to 8600 m. Regional median glacier elevations vary from 4150 m (Pamir Alai) to almost 5400 m (Karakoram), which is largely due to differences in temperature and precipitation. Supraglacial debris covers an area of 3587±662 km2, i.e. 10 % of the total glacierized area. Larger glaciers have a higher share in debris-covered area (up to >20 %), making it an important factor to be considered in subsequent applications (https://doi.org/10.1594/PANGAEA.894707).

scholarly journals Structurally controlled hazard mapping of Southern Leyte, Philippines

2015 ◽  
Vol 3 (10) ◽  
pp. 5891-5921
Author(s):  
P. K. Luzon ◽  
K. P. Montalbo ◽  
J. A. M. Galang ◽  
J. M. Sabado ◽  
C. M. Escape ◽  
...  
Keyword(s):  
Rock Mass ◽  
Debris Avalanche ◽  
The Philippines ◽  
Hazard Mapping ◽  
High Mountain ◽  
Digital Elevation ◽  
Potential Failure ◽  
Elevation Model ◽  
Landslide Hazard Map ◽  
Color Scheme

Abstract. The 2006 Guinsaugon landslide in St. Bernard, Southern Leyte is one of the largest known landslides in the Philippines in recent history. It consists of a 15–20 million m3 rockslide-debris avalanche from an approximately 675 m high mountain weakened by continuous movement of the Philippine fault. The catastrophic Guinsaugon landslide killed 1221 people and displaced 19 000 residents over its 4.5 km path. To investigate the present day morphology of the scar and potential failure that may occur, analysis of a 5 m resolution IfSAR-derived Digital Elevation Model was conducted using Coltop3D and Matterocking software, leading to the generation of a landslide hazard map for the province of Southern Leyte in Central Philippines. The dip and dip-direction of discontinuity sets that contribute to gravitational failure in mountainous areas of the province were identified and measured using a lower Schmidt-Lambert color scheme. After measurement of the morpho-structural orientations, potential sites of failure were analyzed. Conefall was then utilized to compute the extent of rock mass runout. Results of the analysis show instability in the scarp area of the 2006 Guinsaugon landslide and in adjacent slopes because of the presence of steep discontinuities that range from 45–60°. Apart from the 2006 Guinsaugon landslide site, runout models simulated farther rock mass extent in its adjacent slopes, revealing a high potential for fatal landslides to happen in the municipality of St. Bernard. Concerned agencies may use maps produced in the same manner as this study to identify possible sites where structurally-controlled landslides can occur. In a country like the Philippines, where fractures and faults are common, this type of simulated hazard maps would be useful for disaster prevention and facilitate disaster risk reduction efforts for landslide-susceptible areas.

scholarly journals Avalanche situation in Turkey and back-calculation of selected events

2014 ◽  
Vol 2 (1) ◽  
pp. 581-611
Author(s):  
A. Aydın ◽  
Y. Bühler ◽  
M. Christen ◽  
I. Gürer
Keyword(s):  
Simulation Software ◽  
High Mountain ◽  
Identification Algorithm ◽  
Snow Avalanches ◽  
Black Sea Region ◽  
Mountain Ranges ◽  
Digital Elevation ◽  
Back Calculation ◽  
Elevation Model ◽  
Very High

Abstract. In Turkey, an average of 24 people dies in snow avalanches every year, mainly in the eastern part of Anatolia and in the eastern Black Sea Region where high mountain ranges are close to the sea. The proportion of people killed in buildings is very high (87%), especially in comparison to other European and American countries. In this paper we discuss avalanche occurrence, the climatic situation and historical avalanche events in Turkey; in addition, we identify bottlenecks and suggest solutions to tackle avalanche problems. Furthermore, we have applied the numerical avalanche simulation software RAMMS combined with a Digital Elevation Model (DEM)-based potential release zone identification algorithm to analyze the catastrophic avalanche events in the villages of Üzengili (Bayburt province) in 1993 and Yaylaönü (Trabzon province) in 1981. The results demonstrate the value of such an approach for regions with poor avalanche databases, enabling the calculation of different scenarios and the estimation of run-out distances, flow velocities, impact pressure and flow height.

scholarly journals A methodology for the preliminary characterisation of the river boundary condition in finite difference groundwater flow numerical models

2019 ◽  
Vol 8 (3) ◽  
Author(s):  
Manuel M. Oliveira ◽  
Tiago N. Martins
Keyword(s):  
Boundary Condition ◽  
Finite Difference ◽  
Numerical Models ◽  
Regional Scale ◽  
River Stage ◽  
Digital Elevation ◽  
Model Cell ◽  
Gis Environment ◽  
Elevation Model

The characterization of the river boundary condition in finite difference numerical models based on MODFLOW requires the quantification of a set of parameters, some of them usually difficult to define. A methodology is presented based on the digital elevation model (DEM) and the river network, to characterize two of these parameters: the stage of the river and the length of the river in each model cell. Suggestions are presented for the other parameters such as the riverbed bottom elevation and the width of the river to be calculated as a function of the river stage, and the riverbed thickness and hydraulic conductivity. The part of the methodology depending on the DEM is explained and demonstrated using a GIS environment with reference to the GIS tools needed to produce the main steps. This methodology produces more representative values of the river stage parameter if at least 9 DEM cells per model cell are used. This methodology allows a first approximation, at a regional scale, for the characterization of the river boundary condition in numerical modelling.

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