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Paper Number: 96

Field evidences of Gorkha Earthquakes of 25 April (7.8M) and Kodari Earthquake 12 May 2015 (7.2M) in Nepal

Kumar,A¹, Singh M.D.² and Roy L. S.³

¹Department of Earth Sciences, Manipur University, Imphal 795003 Manipur, India

25 April 2015 Gorkha Earthquake and 12 May 2015 Kodari Earthquake have taken a devastating toll in Nepal and neighbouring region as well as envisaged many scientific, engineering and social issues to be addressed for future earthquake research and preparedness. The present studies envisage the visit of the various damaged sites affected by recent earthquakes in Nepal. The April 25, 2015 M 7.8 Gorkha earthquake occurred as the result of thrust faulting near the Main Frontal and May 12, 2015 M 7.3 Kodari earthquake occurred as thrust faulting near the decollément associated with the Main Himalayan Thrust, which defines the interface between the underthrusting Indian plate and the overriding Eurasian plate to the north. The 7.8 M main shock had approximate dimensions of ~120x80 km, directed from its hypocentre eastwards, and towards Kathmandu. Events of the size of the 7.3 M earthquake are typically about 55x30 km in size (length x width) took place at east of it. It is located just beyond the eastern end of that rupture (NOAA 2015), however, it is not considered as aftershocks of 7.8 M. These earthquakes induced many mass movements in mountainous areas and resulted in landslide lakes, which could be another cause of secondary disasters. The earthquake (7.8M) also triggered a major avalanche on the south slopes of Mt. Everest, located approximately 160 km ENE of the epicentre. The assessment of existing infrastructures damages on Intensity scale ranging VII-IX classes. The maximum damage is caused by the overlapping areas of both earthquakes in Sindhupalchok district of Nepal.