LANDSLIDE RISK MITIGATION: A REGIONAL SYSTEMS APPROACH TO A GLOBAL PROBLEM

Ground failure is a geologic hazard that seriously impacts virtually every country in the world. This hazard causes billions of dollars in losses annually and even though our state of knowledge provides for methodologies and technologies to identify and mitigate landslide hazards the losses continue to escalate. In part, this escalation is due to man’s expansion into geologic terrains that are, based upon slope, composition, structure, and water conditions, highly susceptible to ground failure. Further, the natural terrain is being concurrently modified by man and by natural processes, which severely impacts the natural stability of that terrain. Landslides and debris flows have become one of the primary causes of human loss as a collateral hazard related to other catastrophic events, such as hurricanes, earthquakes, and volcanic eruptions. Multi-hazard events in El Salvador, the western United States, Venezuela, the Philippines, and Vietnam are recent tragic case histories. The combination of populations and facilities being sited in high hazard areas, with reduction of the natural stability of those areas, and the introduction of triggering collateral hazards has resulted in staggering increases in the loss of life and property. The international community can substantially reduce annual losses from ground failure by adopting systematic approaches to hazard mitigation, which requires actions before, during and after landslide events. Some of these actions are passive (e.g. land-use planning, incentive programs, building codes, education) and some are proactive (hazard and risk analyses, monitoring and warning systems, engineering, land and structure condemnation, civil suits). The transfer of accurate, reliable, timely information is the key to mitigating the risk through these kinds of actions. The scientific and technical communities must take the lead, enlisting the support of national to local government entities, to support systematic mitigation actions at the regional and local levels.