GEER Report Now Available

July 29, 2015 by  
Filed under Geotechnical Impacts

In May and June of 2015, a team put together by the Geotechnical Extreme Events Reconnaissance (GEER) Association visited Nepal to evaluate the geotechnical damage and effects spurred by the recent earthquake sequence. Landslides, ground failures, damage to hydropower projects, roadways, bridges and buildings were among the features observed. A report of the team’s findings, complete with photos and preliminary analyses, is available on the GEER Association website through the link below:

GEER Report: Gorkha (Nepal) Earthquake of April 25, 2015

UPDATE: Landslides (General Observations)

July 6, 2015 by  
Filed under Geotechnical Impacts

Updated Map of Landslides Triggered by Ghorka Earthquake and Aftershocks
Posted by Patrick Bassal and Ashly Cabas
7/6/15

 

An updated landslide intensity map (including landslides caused by both the 25 April Ghorka Earthquake and the 12 May Dolakha Earthquake) has been posted to the Earthquakes without Frontiers blog. Approximately 5600 landslides have been mapped as of 10 June 2015.

 

Nepal_LS_LowRes_Col1

 

Landslides have been a major problem since the earthquakes hit in Nepal. AGU’s landslide blog has a recent update concerning the Araniko Highway (a major link connecting Nepal with Tibet and China). Much of the highway has been littered with landslide debris, thus shutting down a necessary trade route. As the monsoon season is just underway, it will be critical to stay aware of the imminent landslide risks they may pose.
 

Some of the latest information concerning landslides in Nepal is being continuously updated in the following blogs:

Earthquakes Without Frontiers Blog (UK)

American Geophysical Union: The Landslide Blog

 

Landslide Hazard Analysis (University of Michigan)
Posted by Patrick Bassal and Ashly Cabas
6/11/15

 
Some researchers at the University of Michigan (U-M) have performed an analysis of landslide hazards associated with the recent Nepal earthquakes. Their analysis of landslide risk was performed using a computer analysis that looked at the earthquake ground motions, slope steepness, and strength of rock types. Their website contains downloadable “.kmz” files depicting the areas that may have experienced landslides or have an increased risk of landslides due to the earthquakes.

 

“Information from the U-M-led study has been shared with the U.S Geological Survey, NASA, the U.S. Agency for International Development and other responding agencies. It is being used help prioritize both satellite observations and the analysis of data from those satellites, said Clark, an associate professor in the U-M Department of Earth and Environmental Science.”

 

More information and downloadable content is provided in the links below:

 

April 28, 2015 Landslides News Release (U-M)

 

U-M Nepal Earthquake Data/Download Site

 

Preliminary Map of Landslides Triggered by Earthquake
Posted by Patrick Bassal
5/7/15

 

Research groups in the UK have been working to identify large landslides that are blocking valleys, affecting villages, and disrupting the infrastructure in Nepal. Their observations are based on satellite imagery taken from multiple sources (see map posted below). Their preliminary findings and recommendations for field study can be found in the Earthquakes Without Frontiers link below. One of the most significant observations is that the zone mapped to have intense landsliding corresponds to areas with high rates of past landslides triggered by rainfall. It is thus necessary to assess the hazard associated with these potential landslides before the upcoming monsoon season, expected to start in late June.
Source: http://ewf.nerc.ac.uk/blog/

Source: http://ewf.nerc.ac.uk/blog/

 

 

Preliminary Geotechnical Damage Survey

May 19, 2015 by  
Filed under Geotechnical Impacts

Posted by Brett Maurer
19-May-2015

The following is a preliminary survey of geotechnical damage, to include observations  of:

Liquefaction/lateral spreading
Ground settlement
Ground-failure induced building damage
Landslides
Retaining wall and pavement failures
Damage to an earth dam
Possible site-response effects

The survey was performed by representatives of the JSCE, JGS, ATC3, and ISSMGE societies.

Preliminary Geotechnical Damage Survey

Pre-Gorkha EQ Landslides in Nepal (2)

May 19, 2015 by  
Filed under Geotechnical Impacts

Posted by Diane Moug
18-May-2015

Natural and human-induced landsliding in the Garhwal Himalaya of northern India
Patrick L. Barnard, Lewis A. Owen, Milap C. Sharma, Robert C. Finkel
Geomorphology 40 (2001) 21-35
This paper looks at the effects of a M 6.6 earthquake that took place March 28th, 1999 in the Garhwal Himalaya. “The earthquake was focused ~10.8 km WNW of Camoli (30.49 degrees N, 79.29 degrees E) at a depth of ~15km.”
Within the study area, the earthquake initiated about 50 small landslides. The setting of this study is very close to Nepal, and appears to have a very similar geological setting.

Trends in landslide occurrence in Nepal 2007
David N. Petley, Gareth J. Hearn, Andrew Hart, Nicholas J. Rosser, Stuart A. Dunning, Katie Oven, Wishart A. Mitchell
October 2007, Volume 43, Issue 1, pp 23-44
Natural Hazards
“The aim of the study reported here is to compile and evaluate data regarding the temporal trends in landslide occurrence in Nepal in the period 1978-2005 and to use these data to attempt to understand the underlying causes of changes in landslide impacts through time.”

Pre-Gorkha EQ Landslides in Nepal (1)

May 9, 2015 by  
Filed under Geotechnical Impacts

The following listings provide resources and information concerning recent landslides that have occurred in Nepal (nearby the Gorkha region), before the April 25, 2015 earthquake.

Data compiled by: Diane Moug

Read more