Study on the debris flow disasters occurred in Chugoku and Northern Kyushu due to the 2009-7 Heavy Rain and the prevention to debris flow disaster

（1）灾害概况：2009年7月的暴雨导致霍福地区和福冈县的北方半部发生多起泥石流和山体滑坡，共造成27人死亡。（2）关于泥石流灾害：霍福泥石流灾害是在泥石流中的大石块沉降出来后，房屋被泥石流掩埋而发生的。从岩土工程的角度分析了风化土滑坡的发生与孔隙水压力的关系。对石原泥石流进行的分析评估了被冲走的泥浆量，并确认了Sabo结构的有效性。（3）信息传递与防灾避难系统：明确了泥石流（滑坡）灾害防灾避难信息的收集与传递、防灾避难系统的建立、泥石流（滑坡）灾害防灾地区防灾避难系统的建立等方面的现状和需要解决的问题。

(1)Outline of the disasters : Due to the heavy rain in July 2009, a number of debris flows and landslides occurred in Hofu area and northern half of Fukuoka prefecture, and totally 27 people were killed. (2)About the mudflow disasters : Mud flow disasters in Hofu occurred as the houses were buried by the mud flows, after the big stones in the debris flows had settled out. Examinations from geotechnical approach, the relationship between the occurrence of the landslides at decomposed soils and pore pressure has been implied. Analysis done for debris flow at Ishihara evaluated quantity of the mud washed out, and the effectiveness of the Sabo structure has been confirmed. (3)Information transmission and the system for precaution/ refuge : The present situation and the problems to be solved have been made clear for the gathering/ transmission of the information for disaster prevention/refuge, the establishment of the precaution/refuge system, and the establishment of the precaution/refuge system at the zones where the specification of the precaution to debris flows/landslides have been given.