VERSTAPPEN H.T.
Satellite remote sensing, geomorphological survey and natural hazard zoning. Some new development at ITC, The Netherland
Abstract
Diversified developments in aerospace technology during the last few decades have led to digital terrain data and high-resolution imagery becoming readily available also for surveying and mapping of natural hazards. Multispectral data increase the survey efficiency while multi-temporal data facilitate monitoring and thus contribute to the establishment of early warning systems. The SPOT satellite, launched in February 1986, is the most perfected second-generation operational resource satellite. It has a spatial resolution of 10 m in the panchromatic mode and of 20 m in the multi-spectral mode. Its temporal resolution is in the order of a few days while, crucially important for geomorphological applications, also stereoscopy is provided. The methodology of natural hazard surveying and mapping likewise is rapidly developing. Both analytical geomorphological data and synthetic data of terrain are required for the purpose of hazard zoning, but usually only a part of the information obtained by these two survey technologies is in fact of direct relevance. In order to increase the survey efficiency therefore a pragmatic type of survey is opted for, using a tailor-made legend for the purpose of the survey at hand. Digital data handling leading up to a geographical information system with a data base and a rule base geared to hazard-related environmental (and other) factors is of growing importance to cope with the problem of the cascade of data provided and required. Examples are given of an attempt at earthquake hazard zoning in Southern Italy and of mountain hazards in the Nepalese Himalayas.