LABORATORY EXPERIMENTS ON THE RUNUP OF LEADING-DEPRESSION N-WAVES

Real tsunamis often lead with a depression wave, causing coastal water level to lower before the main tsunami wave arrives and floods the coast. The widely used benchmark wave, the solitary wave, cannot capture this phenomenon, in addition to the many drawbacks in using the solitary wave as a model tsunami wave form (Madsen et al. 2008). Although alternative tsunami wave forms have been proposed to capture the water level withdrawal phenomenon, in particular the leading- depression N-waves (LDN), a consistent method for generating and characterizing LDNs had been lacking. In this study we adopt the Lima et al. (2019) wave generation method to consistently generate LDNs in the laboratory. By comparing the evolution, shoaling, and runup processes of LDNs to those due to solitary waves of the same wave amplitude, we seek to identify the differences and similarities between the runup of LDNs and the runup of solitary waves. The ultimate objective is to provide a link between LDNs and solitary waves, so that the vast existing knowledge on solitary waves can be extended to study LDNs.