Seismic response of Imja Lake moraine dam and outlet structure under Kobe and Chile earthquakes

This study compares the seismic response of the Imja Lake terminal moraine dam and the 2016 man-made outlet structure in Nepal's Khumbu region under two strong earthquakes: Kobe (1995, PGA 0.83g) and Chile (2014, PGA 0.58g). Using PLAXIS 2D, the moraine was modeled with a hardening soil model, and the outlet structure with linear elastic and plate elements. Results show the moraine dam experienced large displacements (up to 28 cm) and shear strains (>5%) under Kobe loading, indicating potential failure. In contrast, the outlet structure showed lower deformation and better stability. These findings highlight the improved seismic resilience of outlet structure and the need for site-specific seismic design for glacial lake safety.