Detection and alert
Early detection and alert of ongoing events is a crucial factor to ensure that appropriate response measures can be taken in a timely manner. Under certain circumstances, early detection and alert of ongoing incidents can even greatly attenuate their consequences. For instance, human loss resulting from the 26 December 2004 Indian ocean tsunami could have been greatly reduced if an efficient tsunami detection and alert system had been put in place, allowing the population of neighbouring islands to shelter before the deadly wave hit their islands.
Use of satellite images, positioning systems, communication aids and web-crawler tools to systematically screen news stories posted on the web, can all warn of impending disasters. Networks of organizations and groups also collect relevant health intelligence from around the world, and all leads are assessed and verified, with alerts issued if required.
As part of the revised International Health Regulations (IHR 2005), WHO has been developing a system to rapidly identify, verify and alert for incidents of (potential) international public health concern, including those involving environmental health hazards. This system is a technical collaboration between existing institutions and networks including the Global Outbreak Alert and Response Network (GOARN), the Global Public Health Information Network (GPHIN), as well as ChemiNet.