Geotechnical Aspects of Sikkim Earthquake of September 18, 2011

There was wide spread ground failure and landslide during the recent Sikkim earthquake (Magnitude ML = 6.9) of September 18, 2011. An intensive damage survey was carried out after a week of the earthquake. This paper presents the results of a reconnaissance study in Sikkim. The various geotechnical aspects of the damage caused by earthquake including landslides, failure of retaining walls, foundation failures, damage to roads and creep of soil due to ground shaking have been investigated. The maximum damage was observed in Lachung, North Sikkim district. The paper presents the geotechnical aspects of damages correlating it with level of shaking (intensity on MSK scale) and epicentral distances at different locations. It was found that major damage was due to landslides and failure of retaining walls which in turn are due to movement of soil. In this paper, causes of damages have been investigated and remedial measures, to avoid these in future earthquakes, are suggested.