scholarly journals The Use of Lichenometry for Assessment of the Destruction and Reconstruction of Buddhist Sacred Walls in Langtang Valley, Nepal Himalaya, Following the 2015 Gorkha Earthquake

2017 ◽  
Vol 49 (1) ◽  
pp. 61-79 ◽  
Author(s):  
Steven H. Emerman
Keyword(s):  
Gorkha Earthquake ◽  
Nepal Himalaya ◽  
2015 Gorkha Earthquake ◽  
Langtang Valley

scholarly journals Multiple remote-sensing assessment of the catastrophic collapse in Langtang Valley induced by the 2015 Gorkha earthquake

2017 ◽  
Vol 17 (11) ◽  
pp. 1907-1921 ◽  
Author(s):  
Hiroto Nagai ◽  
Manabu Watanabe ◽  
Naoya Tomii ◽  
Takeo Tadono ◽  
Shinichi Suzuki
Keyword(s):  
Monsoon Season ◽  
Deposition Process ◽  
Visual Interpretation ◽  
Gorkha Earthquake ◽  
Water Stream ◽  
2015 Gorkha Earthquake ◽  
Himalayan Mountain ◽  
Hazard Process ◽  
Langtang Valley

Abstract. The main shock of the 2015 Gorkha Earthquake in Nepal induced numerous avalanches, rockfalls, and landslides in Himalayan mountain regions. A major village in the Langtang Valley was destroyed and numerous people were victims of a catastrophic avalanche event, which consisted of snow, ice, rock, and blast wind. Understanding the hazard process mainly depends on limited witness accounts, interviews, and an in situ survey after a monsoon season. To record the immediate situation and to understand the deposition process, we performed an assessment by means of satellite-based observations carried out no later than 2 weeks after the event. The avalanche-induced sediment deposition was delineated with the calculation of decreasing coherence and visual interpretation of amplitude images acquired from the Phased Array-type L-band Synthetic Aperture Radar-2 (PALSAR-2). These outline areas are highly consistent with that delineated from a high-resolution optical image of WorldView-3 (WV-3). The delineated sediment areas were estimated as 0.63 km2 (PALSAR-2 coherence calculation), 0.73 km2 (PALSAR-2 visual interpretation), and 0.88 km2 (WV-3). In the WV-3 image, surface features were classified into 10 groups. Our analysis suggests that the avalanche event contained a sequence of (1) a fast splashing body with an air blast, (2) a huge, flowing muddy mass, (3) less mass flowing from another source, (4) a smaller amount of splashing and flowing mass, and (5) splashing mass without flowing on the east and west sides. By means of satellite-derived pre- and post-event digital surface models, differences in the surface altitudes of the collapse events estimated the total volume of the sediments as 5.51 ± 0.09  ×  106 m3, the largest mass of which are distributed along the river floor and a tributary water stream. These findings contribute to detailed numerical simulation of the avalanche sequences and source identification; furthermore, altitude measurements after ice and snow melting would reveal a contained volume of melting ice and snow.

scholarly journals 25 April 2015 Gorkha Earthquake in Nepal Himalaya (Part 2)

2017 ◽  
Vol 141 ◽  
pp. 235
Author(s):  
N. Purnachandra Rao ◽  
Roland Burgmann ◽  
Jean-Louis Mugnier ◽  
Vineet Gahalaut ◽  
Anand Pandey
Keyword(s):  
Gorkha Earthquake ◽  
Nepal Himalaya ◽  
2015 Gorkha Earthquake

Factors Contributing Building Reconstruction and Renovation Challenges: A Case Study after April 2015 Gorkha Earthquake

2020 ◽  
Author(s):  
Krishna P. Kisi ◽  
Rujan Kayastha ◽  
Nipesh Pradhananga ◽  
Joseph Shrestha ◽  
Dibangar Khoteja
Keyword(s):  
Gorkha Earthquake ◽  
2015 Gorkha Earthquake ◽  
Building Reconstruction

scholarly journals The Influence of Surface Topography on the Weak Ground Shaking in Kathmandu Valley during the 2015 Gorkha Earthquake, Nepal

Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 678
Author(s):  
Mark van der Meijde ◽  
Md Ashrafuzzaman ◽  
Norman Kerle ◽  
Saad Khan ◽  
Harald van der Werff
Keyword(s):  
Numerical Simulations ◽  
Surface Topography ◽  
Seismic Energy ◽  
Spectral Element ◽  
Kathmandu Valley ◽  
Ground Displacement ◽  
Gorkha Earthquake ◽  
Ground Shaking ◽  
Earthquake Scenarios ◽  
2015 Gorkha Earthquake

It remains elusive why there was only weak and limited ground shaking in Kathmandu valley during the 25 April 2015 Mw 7.8 Gorkha, Nepal, earthquake. Our spectral element numerical simulations show that, during this earthquake, surface topography restricted the propagation of seismic energy into the valley. The mountains diverted the incoming seismic wave mostly to the eastern and western margins of the valley. As a result, we find de-amplification of peak ground displacement in most of the valley interior. Modeling of alternative earthquake scenarios of the same magnitude occurring at different locations shows that these will affect the Kathmandu valley much more strongly, up to 2–3 times more, than the 2015 Gorkha earthquake did. This indicates that surface topography contributed to the reduced seismic shaking for this specific earthquake and lessened the earthquake impact within the valley.

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