From November 2017 to March 2018, in Japan, atmospheric pressure pattern in winter often increased. In particular, heavy snow was observed on the Japan Seaside from northern Japan to western Japan from February 3rd to 8th. Due to heavy snow, various problems occurred in Fukui and Ishikawa prefectures, such as road closures, railway suspensions, aircraft cancellations and so on. In this study, we examined actual situation about influences on civil life. In this study, Kanazawa City and Fukui City areas were set, and questionnaire surveys and newspaper articles were used for analysis. We report result of detailed examination about the behavior and impact of Kanazawa and Fukui citizens during heavy snow.

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eavy rain hit Shiso city in July 2018 and a flank collapse occurs. A large amount of driftwood flows into a river channel. A logjam blocked the river and increased flood damage. Consequently, the detour flow occurred around the bridge and the high-speed flood-flow caused bed erosion in the nearby area. This report examines the source location of driftwood, number of driftwood and flood damage by driftwood that occurred in Shiso city.

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Duration and intensity characteristics of heavy rainfall that caused sediment disaster were studied. First, we classified the types of heavy rainfall into three types: high active heavy rainfall with extremely high intensity and short duration(hereinafter, it is written as H.A.H.R.), active heavy rainfall with very high intensity(hereinafter, it is written as A.H.R.), long active heavy rainfall with high intensity and long duration (hereinafter, it is written as L.A.H.R.). The heavy rain defined in this study is high intensity rain at the beginning and the end of the period including 2 hours of no rainfall. Here, heavy rainfall is defined as rainfall of 15 mm/h or more, and no rainfall is rainfall less than 0.5 mm/h. The characteristics of rainfall duration (t_d) and rainfall intensity ( i= R_H/t_d, R_H: cumulative heavy rainfall) were analyzed for the events of remarkable heavy rainfall. As a result, the duration (t_d)of H.A.H.R., A.H.R. and L.A.H.R. are estimated to be 3 to 12 hours, 12 to 36 hours, 36 to  xhours, respectively. The upper limits of rainfall intensity ( i) of these three types of heavy rainfall were estimated to be 70 mm/h, 36 mm/h and 20 mm/h, respectively.

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In recent years, seismic damages have occurred in residential areas which are artificially filled grounds. In this study, ground vibration characteristics and subsurface structures of artificially filled grounds were estimated based on microtremor observations. We conducted several linear microtremor array measurements and a large number of three-component observations at two residential development areas in Fukui prefecture. The phase velocities of Rayleigh waves were calculated by using the extended SPAC method on linear array observations. The thickness of soil layers were back-analyzed based on H/V spectra. The 3D subsurface structures of the ground were modeled using space interpolation based on each estimated structure beneath the observation points. By comparing with existing elevation data, the validity of the estimated structures were confirmed.

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