Tsunami Squares modelling of the 2015 June 24 Hongyanzi landslide generated river tsunami in Three Gorges Reservoir, China

On 2015 June 24, a 230 000 m(3) landslide slid into the triangle bayou at the intersection of the Yangtze and Daning Rivers and generated a river tsunami that ran up 6.2 m on the opposite shoreline at Wushan town. The slope failure and resulting waves killed two people and damaged many shipping facilities. Based on field surveys and eyewitness observations, we apply the 'Tsunami Squares' method to model the Hongyanzi landslide and its generated waves. Landslide simulations indicate a maximum impact velocity of similar to 16 m s(-1) that matches well with an eyewitness video. The computed post-slide mass stopped on the near river bed with a shape fitting the observed geological profile. Tsunami simulations reveal a large region of wave impacts that coincide with the observed run-up heights. The successful reproduction of the dynamics of this landslide-generated river tsunami emphasizes the capacity and efficiency of Tsunami Squares modelling in emergency reaction and risk assessment.