Design of the geohazard monitoring and warning system in Wenchuan earthquake area

The Wenchuan earthquake on May 12, 2008 has induced many secondary disasters, such as collapse, landslide, and dammed lake. These provide conditions for debris flows, which are expected to be one of the major disasters in the quake area in the coming years. A network of monitoring and warning of the geohazards is urgent for the hazard mitigation and homeland reconstruction. About 2998 monitoring sites and six systems are planned in the quake area of Sichuan. These systems should be automatic and timing, with low power cost, wireless communication, and proper power support. The monitored objects and monitoring methods are designed following the existing system at home and abroad. A systematic imagine is proposed on base of the previous studies. The system consists mainly of the forming conditions, stimulus factors, information management platform, and alarming block. Two special techniques are analyzed in details: The critical indices for hazard formation and the networks of information transfer. For the latter, a wireless sensor network is introduced, which arises as a new method in acquiring information with variety of network forms. Such a network can be randomly distributed, self-organized, and run in coopera-tion. Combining with the statewide cellular base stations of China Mobile and China Unicom, the system can run in long-term to monitor landslides, dammed lakes, and debris flows from different viewpoints and release alarms. Fi-nally, a flow framework is plotted according to the objects of monitoring.