###### Abstract  
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. synthetic aperture radar; InSAR; coherence; temporal decorrelation; change detection; COSMO-SkyMed; archaeology; geoglyphs; Nasca lines; Peru 2018 10 572 2018 11 March 2018 28 March 2018 2018 10 572 2018 10 5  
With regard to the heritage conservation, the Lines are exposed to continuous or frequent interactions with local weather and natural surface processes, as well as the human presence and its use of the land. Indeed, the last official State of Conservation report published by UNESCO cites, among others, the following human-related factors affecting the WHS: damage caused by illegal mining and farming activities, continued vehicle traffic through the geoglyphs, lack of systematic monitoring of the property, and planned infrastructure projects [4]. Concerns have been expressed in the past years about the impact on the conservation of the Lines due to climate change and potential for flooding caused by El Nino (e.g., [5; 6]). There is also a history of events due to human action that have been reported in official reports, press releases of the Ministry of Culture of Peru, media, and published literature, for the surface damage and landscape disturbance they caused at various locations of this hugely wide WHS (e.g., [7; 8; 9; 10]). In this paper, a focus on a couple of these well-documented anthropogenic events is provided to demonstrate that synthetic aperture radar (SAR) images with high spatial resolution (HR), acquired regularly from X-band space-borne sensors (frequency range 8-12 GHz; wavelength range 2.5-3.75 cm), can be used to undertake digital fieldwork and create a digital record for the substantiation of site disturbance events. It is not the first time that the Nasca Lines are studied using space-borne SAR, although most of the investigations relied on C-band SAR data (frequency range 4-8 GHz; wavelength range 3.75-7.5 cm). In previous publications, for instance, the value of archive C-band data to analyse retrospectively landscape changes was proved [11] and the condition of heritage assets--either at surface or brought back to light by archaeological excavations--was assessed based on time series of calibrated radar backscatter and its normalized coefficient (sigma nought, \(\sigma^{0}\)) [12].