ESTIMATION OF RUNUP VELOCITY OF THE STORM SURGE CAUSED BY 2019 TYPHOON No. 15 (FAXAI) USING VIDEO ANALYSIS

Abstract

 The storm surges and high waves of Typhoon No. 15 in 2019 caused extensive damage, including inundation of reclaimed land and damage to parapets, along the coast of Yokohama City. In this study, we simply estimated the run-up speed of storm surge by tracking drifting objects in the video images captured by a camera installed at about 420 m from the coastline, Kanazawa Ward, Yokohama City. The video images showed that the water level was almost constant for about 15 minutes and that multiple drifting objects were moving upstream due to the pushing waves. The mean value was 0.70 m/s with a standard deviation of 0.06 m/s. The coupled storm surge-wave model SuWAT was used to analyze the storm surge run-up considering the wave setup effect caused by high waves, and the results showed that the inundation at the target area was not analyzed and underestimated. In the future, simultaneous analysis of wave overtopping caused by the urges and the high waves will be conducted to clarify the cause of the storm surges run-up.