Study on Earthquake-Induced Sloshing Waves in Moraine-Dammed Lakes

Abstract

Large surface water waves can be triggered in moraine-dammed lakes during earthquakes and may lead to the overtopping failure of moraine dams. In the earthquake-prone Himalayas, there are thousands of moraine-dammed lakes; their outburst may lead to catastrophic disasters (e.g. floods and debris flow), posing severe threats to humans and infrastructures downstream. This paper experimentally studied earthquake-induced water waves (EWWs) in moraine-dammed lakes and examined the effects of several factors (e.g. water depth, earthquake parameters, and uneven lake basin). The experimental results suggest that the EWWs positively correlate to the earthquake wave, and the maximum height of the EWWs increases by 10%–15% when the effect of the uneven lake basin is considered. Based on the experiment data, we derived a calculation equation to estimate the maximum amplitude of EWWs considering the basin effect, and proposed a fast risk assessment method for moraine lakes due to overtopping EWWs. Finally, based on the method, we assessed the failure risk of the moraine lakes located in the Gyirong river basin where the China–Nepal corridor crosses. The study broadens understandings of the risk source of moraine-dammed lakes.