Author(s): Satoru Matsuda, Yotaro Nishi, Tsuyoshi Ikeshima, Takahiro Itoh, Takahisa Mizuyama
Linked Author(s): Satoru Matsuda
Keywords: Debris flow, Peak discharge, Hydrograph, Vibration meter
Abstract: Debris flow disaster took place at Nashi-zawa creek in Kiso River basin, Nagano Prefecture on 9th July in 2014 due to intensive rainfall of the typhoon Neoguri. A CCTV camera and a high sensitivity seismometer were installed along Nashi-zawa creek, a high sensitivity seismometer was at the ground about 104 m in depth, 10 m apart from the river center of Nashi-zawa creek and in around 500 m downstream reach from CCTV camera. Surges of debris flows were recorded by CCTV camera, though the camera was destroyed by those surges. Acceleration of the vibration recorded by seismometer took place two peak of acceleration when debris flows runoff was estimated by hearing survey to local residential persons. There is not research related to estimation of debris flows hydrograph using a high sensitivity seismometer, though there were researches related to estimation of debris flows magnitude using a high sensitivity seismometer. In present study, hydrograph is estimated using discharge by CCTV camera data and fitting curve of relations of between debris flow discharge and acceleration of vibration. Peak discharge extrapolated from peak acceleration of the vibration is estimated about 756 m3/s. The estimation was similar to peak discharge (490. 5 to 889. 6 m3/s) through free surface traces by field survey just after disaster. In addition, relationship between estimated peak discharge and total discharge with estimated hydrograph took almost same order value in comparison with previous data
Year: 2017