scholarly journals Rapid Terrain Assessment for Earthquake-Triggered Landslide Susceptibility With High-Resolution DEM and Critical Acceleration

2021 ◽  
Vol 9 ◽  
Author(s):  
Season Maharjan ◽  
Kaushal Raj Gnyawali ◽  
Dwayne D. Tannant ◽  
Chong Xu ◽  
Pascal Lacroix
Keyword(s):  
High Resolution ◽  
Landslide Susceptibility ◽  
Earthquake Ground Motion ◽  
Depth Information ◽  
Gorkha Earthquake ◽  
Ground Acceleration ◽  
Critical Acceleration ◽  
Field Reconnaissance ◽  
2015 Gorkha Earthquake ◽  
Glaciated Valley

Earthquake ground motion often triggers landslides in mountainous areas. A simple, robust method to quickly evaluate the terrain’s susceptibility of specific locations to earthquake-triggered landslides is important for planning field reconnaissance and rescues after earthquakes. Different approaches have been used to estimate coseismic landslide susceptibility using Newmark’s sliding block model. This model requires an estimate of the landslide depth or thickness, which is a difficult parameter to estimate. We illustrate the use of Newmark sliding block’s critical acceleration for a glaciated valley affected by the 2015 Gorkha earthquake in Nepal. The landslide data came from comparing high-resolution pre- and post-earthquake digital elevation models (DEMs) derived from Spot 6/7 images. The areas where changes were detected provided an inventory of all the landslides triggered by the earthquake. The landslide susceptibility was modeled in a GIS environment using as inputs the pre-earthquake terrain and slope angles, the peak ground acceleration from the 2015 Gorkha earthquake, and a geological map. We exploit the depth information for the landslides (obtained by DEM difference) to apply the critical acceleration model. The spatial distribution of the predicted earthquake-triggered landslides matched the actual landslides when the assumed landslide thickness in the model is close to the median value of the actual landslide thickness (2.6 m in this case). The landslide predictions generated a map of landslide locations close to those observed and demonstrated the applicability of critical acceleration for rapidly creating a map of earthquake-triggered landslides.

Damage Reconnaissance of Unreinforced Masonry Bearing Wall Buildings after the 2015 Gorkha, Nepal, Earthquake

2017 ◽  
Vol 33 (1_suppl) ◽  
pp. 243-273 ◽  
Author(s):  
Giuseppe Brando ◽  
Davide Rapone ◽  
Enrico Spacone ◽  
Matt S. O'Banion ◽  
Michael J. Olsen ◽  
...  
Keyword(s):  
Response Spectra ◽  
Visual Assessment ◽  
Unreinforced Masonry ◽  
Assessment Process ◽  
Gorkha Earthquake ◽  
Field Reconnaissance ◽  
2015 Gorkha Earthquake ◽  
Out Of Plane ◽  
2015 Gorkha Nepal Earthquake

This paper documents and analyzes the seismic behavior of unreinforced masonry (URM) buildings that were damaged by the 2015 Gorkha earthquake in Nepal, and reports on the performance of palaces, giving an overview on the failures suffered by significant examples of these monumental buildings. Field reconnaissance was completed through both rapid, in-situ visual assessment and state-of-the-art procedures utilizing light detection and ranging (lidar) and virtual reality (VR) technologies. Both the visual and virtual assessments were compared for 20 structures and were generally consistent; however, the virtual assessment process enabled detection of damage that could not be captured or was difficult to distinguish in the field observations. Further, both in-plane and out-of-plane mechanisms were analyzed and attributed to specific structural deficiencies that usually characterize poorly detailed masonry buildings. Moreover, wall overturning was correlated with the peculiarities of the pseudo-accelerations and rocking response spectra of the earthquake.

Landslide susceptibility assessment of the region affected by the 25 April 2015 Gorkha earthquake of Nepal

2016 ◽  
Vol 13 (11) ◽  
pp. 1941-1957 ◽  
Author(s):  
Amar Deep Regmi ◽  
Megh Raj Dhital ◽  
Jian-qiang Zhang ◽  
Li-jun Su ◽  
Xiao-qing Chen
Keyword(s):  
Landslide Susceptibility ◽  
Susceptibility Assessment ◽  
Gorkha Earthquake ◽  
Landslide Susceptibility Assessment ◽  
2015 Gorkha Earthquake

scholarly journals The 2015 Gorkha Earthquake and response of the Kathmandu Valley sediments

2015 ◽  
Vol 49 (1) ◽  
pp. 1-5
Author(s):  
Sudhir Rajaure ◽  
Megh Raj Dhital ◽  
Lalu Prasad Paudel
Keyword(s):  
Source Zone ◽  
Great Earthquake ◽  
Kathmandu Valley ◽  
Main Central Thrust ◽  
Gorkha Earthquake ◽  
Ground Acceleration ◽  
Low Frequencies ◽  
High Frequencies ◽  
Nepal Earthquake ◽  
2015 Gorkha Earthquake

The Gorkha Earthquake occurred on the gently dipping part of the Main Himalayan Thrust (MHT), close to the Main Central Thrust (MCT). This earthquake possibly occurred in the source zone of the 1833 Nepal Earthquake (Mw 7.6), which occurred after 182 years. The region between the 1905 Kangra Earthquake and 1934 Bihar-Nepal Earthquake has not produced any great earthquake since the last 500 years and still remains a potential site for great earthquake(s) in future. The Kathmandu Valley witnessed moderate ground acceleration and comparatively large velocity as recorded at Kantipath during the Mw 7.8, Gorkha Earthquake. The analysis of the records show that high frequencies were damped and low frequencies were dominant over the sedimentary basin, which can be attributed to the response of the sediments underneath. Because of damping of high frequencies, the engineered, low storey buildings were less damaged and resisted the ground shaking comparatively well. However, on the other hand, the historical monument 'Dharahara' collapsed completely and the high rise apartment buildings suffered more because of the dominance of low frequencies.

scholarly journals Earthquake-Induced Shallow Landslide Susceptibility Assessment of Gorkha District

2019 ◽  
Vol 5 ◽  
pp. 181-193
Author(s):  
Tapendra Kumar Shahi
Keyword(s):  
Landslide Susceptibility ◽  
Large Scale ◽  
Shallow Landslide ◽  
Earthquake Ground Motion ◽  
Susceptibility Map ◽  
Topographic Effects ◽  
Gorkha Earthquake ◽  
Loss Of Life ◽  
Landslide Inventory Map ◽  
Inventory Map

Nepal is very seriously affected by landslides every year causing loss of life and property. Large scale earthquakes that occurred in different time periods such as on 15th January, 1934 or that on 25th April 2015 have proved Nepal as seismically vulnerable -place. Nepal has witnessed several landslides during and after the earthquake events making some areas of land quite vulnerable for settlement and other usages. Therefore in order to minimize the impacts of landslides caused due to earthquakes, highly susceptible locations should be identified and spatial planning is made accordingly. Considering topographic effects in amplification of earthquake ground motion, Uchida et al. (2004) have developed a topographical parameter based empirical description of landslide susceptibility during an earthquake. In this research, the method proposed by Uchida et al. (2004) is utilized in raster GIS and landslide susceptibility analysis is performed in the study area of SulikotGaupalika of Gorkha district, Nepal which was severely hit by several landslides due to “Gorkha Earthquake 2015". The landslide inventory map of SulikotGaupalika due to “Gorkha Earthquake 2015" is obtained and is correlated with landslide susceptibility values as obtained by using Uchida et al. (2004). The analysis shows that the method proposed by Uchida et al. (2004) is more than 68.9% accurate in delineating the probable locations of earthquake induced landslides. By calibrating landslide data and landslide susceptibility values in a small site (i.e. SulikotGaupalika) within the study area, a final landslide susceptibility map is prepared for the whole study area of Gorkha district. The resultant susceptibility map is very useful for planning settlements, development activities and reconstruction planning.

scholarly journals Landslide susceptibility in Rasuwa District of central Nepal after the 2015 Gorkha Earthquake

2019 ◽  
Vol 59 ◽  
pp. 79-88 ◽  
Author(s):  
Badal Pokharel ◽  
Prem Bahadur Thapa
Keyword(s):  
Land Use ◽  
Landslide Susceptibility ◽  
Google Earth ◽  
Training Dataset ◽  
Slope Aspect ◽  
Gorkha Earthquake ◽  
Central Nepal ◽  
Prediction Rate ◽  
2015 Gorkha Earthquake ◽  
High Resolution Satellite Images

The 2015 Gorkha Earthquake (7.8 Mw) triggered several landslides in central Nepal with major damages in 14 districts. Among them, the Rasuwa district at the north of Kathmandu Valley faced severe landslides due to rugged topography, complex geology and improper land use development. The landslides had blocked the Pasang Lhamu Highway and dammed the Trishuli River at many places. A total of 1416 landslide locations were detected in the district from high resolution satellite images in Google Earth. In this study, landslide susceptibility was modeled in the Rasuwa District by considering slope, aspect, elevation, geology, peak ground acceleration (PGA), land use, drainage proximity and thrust proximity as the predictive factors for landslide occurrences. The landslide inventory was split into 70% and 30% portions as the training dataset and testing dataset respectively. The results from modified frequency ratio (FR) suggest that effect of geology with prediction rate 2.52 is the highest among all factors and is followed by elevation (2.38) and drainage proximity (2.12). The results were verified using area under curve (AUC) and the prediction rate was found to be 79.14%. The computed landslide susceptibility map is helpful for land use planning and landslide risk reduction measure in the Rasuwa District.

scholarly journals Distribution Pattern of Coseismic Landslides Triggered by the 2017 Jiuzhaigou Ms 7.0 Earthquake of China: Control of Seismic Landslide Susceptibility

2020 ◽  
Vol 9 (4) ◽  
pp. 198
Author(s):  
Xiao-li Chen ◽  
Xin-jian Shan ◽  
Ming-ming Wang ◽  
Chun-guo Liu ◽  
Na-na Han
Keyword(s):  
Distribution Pattern ◽  
Landslide Susceptibility ◽  
Landslide Susceptibility Mapping ◽  
Landslide Area ◽  
Ground Acceleration ◽  
Critical Acceleration ◽  
Ground Shaking ◽  
Landslide Occurrence ◽  
Coseismic Landslide ◽  
Seismic Landslide

On 8 August 2017 an earthquake (MS7.0) occurred within Jiuzhaigou County, Northern Aba Prefecture, Sichuan Province, China, triggering 4834 landslides with an individual area greater than 7.8 m2 over a more than 400 km2 region. Instead of correlating geological and topographic factors with the coseismic landslide distribution pattern, this study has attempted to reveal the control from seismic landslide susceptibility mapping, which relies on the calculation of critical acceleration values using a simplified Newmark block model. We calculated the average critical acceleration for each cell of the gridded study area (1 km×1 km), which represented the seismic landslide susceptibility of the cell. An index of the potential landslide area generation rate was defined, i.e., the possible landsliding area in each grid cell. In combination with PGA (peak ground acceleration) distribution, we calculated such indexes for each cell to predict the possible landslide hazard under seismic ground shaking. Results show that seismic landslide susceptibility plays an important role in determining the coseismic landslide pattern. The places with high seismic landslide susceptibility tends to host many landslides. Additionally, the areas with high potential landslide area generation rates have high real landslide occurrence rates, consistent with dominant small-medium scale landslides by this earthquake. This approach can aid assessment of seismic landslide hazards at a preliminary stage. Additionally, it forms a foundation for further research, such as the rapid evaluation of post-earthquake landslides and identifying highly impacted areas to help decision makers prioritize disaster relief efforts.

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