Interferometric coherence for change detection in the Nasca region of Peru

The Nasca Lines in Southern Peru are important for their archaeological and cultural significance as well their impact on local economies as a famous tourist landmark. Recent anecdotal evidence implies that a combination of enhanced El Nino conditions and increased anthropogenic degradation are leading to the gradual erosion of the surface upon which the lines and geoglyphs are etched. A combination of barren desert, wide expanse and centimetre scale impacts makes effective mapping of such a large area very difficult. In this study it is shown that interferometric coherence using ERS data between 1997 and 1999 is sensitive to the small scale degradation across the Nasca pampa. As such it provides a potential tool for long term mapping and quantification of the degradation.