Tracking human-induced landscape disturbance at the Nasca lines UNESCO World Heritage Site in Peru with COSMO-SkyMed InSAR
Francesca Cigna ; Deodato Tapete
Apr - 2018
DOI: 10.3390/rs10040572

journal : Remote Sensing

Volume : 10 ; Issue : 4
type: Article Journal

The “Lines and Geoglyphs of Nasca and Palpa” in Peru are among the most well-known UNESCO World Heritage Sites globally, and an exemplar of site where heritage assets cannot be separated from their natural and anthropogenic environment. The site is exposed to interactions with natural processes, as well as human presence. In this work, 3-m resolution synthetic aperture radar (SAR) StripMap HIMAGE HH-polarised scenes acquired by the X-band COSMO-SkyMed constellation are exploited to track two events of human-induced landscape disturbance that occurred in December 2014 and January 2018. Pre-, cross-, and post-event interferometric SAR (InSAR) pairs characterised by small temporal and normal baselines allow the detection of temporal decorrelation associated with the two events, the extent and time reference of which match with online photographic and video evidence, published literature, web news, and press releases by the Ministry of Culture in Peru. Further elements enhancing the understanding of the 2018 event come from 10-m resolution Sentinel-2B satellite data that reveal the occurrence of apparent changes of surface reflectance due to uncovering of the light grey-yellow clay underneath the darker pebble constituting the fragile surface of the Pampa de Jumana. This scientific study confirms that SAR imagery archives, such as those being built by COSMO-SkyMed for Nasca, prove valuable for the retrospective analysis and digital recording of human-induced landscape disturbance events from space. These archives therefore act as essential sources of geospatial information on the conservation history of heritage sites and assets.

keywords : synthetic aperture radar; InSAR; coherence; temporal decorrelation; change detection; COSMO-SkyMed; archaeology; geoglyphs; Nasca lines; Peru

Notes : AcknowledgmentsProject carried out using COSMO-SkyMed® Products, © of the Italian Space Agency (ASI), delivered under a licence to use by ASI.