NH41B-1818
Landslide occurrences and recurrence intervals of heavy rainfalls in Japan
Thursday, 17 December 2015
Poster Hall (Moscone South)
Hitoshi Saito1,2, Hiroshi Matsuyama2 and Taro Uchida3, (1)Kanto Gakuin University, Yokohama, Japan, (2)Tokyo Metropolitan University, Hachioji, Japan, (3)SABO Planning Division, National Institute for Land and Infrastructure Management, Japan, Tsukuba, Japan
Abstract:
Dealing with predicted increases in extreme weather conditions due to climate change requires robust knowledge about controls on rainfall-triggered landslides. This study developed the probable rainfall database from weather radar data, and analyzed the potential correlation between the landslide magnitude-frequency and the recurrence interval of the heavy rainfall across Japan. We analyzed 4,744 rainfall-induced landslides (Saito et al., 2014, Geology), 1 to 72 h rainfalls, and soil water index (SWI). We then estimated recurrence intervals for these rainfall parameters using a Gumbel distribution with jackknife fitting. Results showed that the recurrence intervals of rainfall events which caused landslides (<10^3 m^3) were less than 10 yr across Japan. The recurrence intervals increased with increases in landslide volumes. With regard to the landslides larger than 10^5 m^3, recurrence intervals of the rainfall events were more than 100 yr. These results suggest that recurrence intervals of heavy rainfalls are important for assessing regional landslide hazard in Japan.
