Increased human risk caused by cascading hazards - A framework.

Cascading hazards occur frequently. Unexpected casualties and losses of properties, or even impacts on the society and the environment may ensue from failure to anticipate the amplified risks induced by cascading hazards. Current risk assessment methods pay relatively less attention to quantifying the increased human risk related to "cascading" events. An improved framework for quantifying the human risk caused by cascading hazards is proposed in this paper. The framework considers the interactions among the cascading hazards and among the vulnerabilities of elements to these hazards. Its kernel is to scientifically anticipate and gear up for any new intensified hazards, which may otherwise lead to serious social aftermath. The framework is illustrated with a multi-hazard example close to the epicenter of the Wenchuan earthquake, which involved a chain of hazards including slope failures, a large debris flow, river damming, and flooding.

Evolution of Mass Movements near Epicentre of Wenchuan Earthquake, the First Eight Years.

It is increasingly clear that landslides represent a major cause of economic costs and deaths in earthquakes in mountains. In the Wenchuan earthquake case, post-seismic cascading landslides continue to represent a major problem eight years on. Failure to anticipate the impact of cascading landslides could lead to unexpected losses of human lives and properties. Previous studies tended to focus on separate landslide processes, with little attention paid to the quantification of long-term evolution of multiple processes or the evolution of mass movements. The very active mass movements near the epicentre of the Wenchuan earthquake provided us a unique opportunity to understand the complex processes of the evolving cascading landslides after a strong earthquake. This study budgets the mass movements on the hillslopes and in the channels in the first eight years since the Wenchuan earthquake and verify a conservation in mass movements. A system illustrating the evolution and interactions of mass movement after a strong earthquake is proposed.