# Detection of Crustal Uplift Deformation in Response to Glacier Wastage in Southern Patagonia
###### Abstract
In recent decades, GPS stations have been placed on the edge, both sides, of the SPI with the objective of monitoring crustal deformation of the South American plate ([25], among others). This allows researchers to establish that GIA is one of the primary components explaining the crustal observed deformation, with another factor being the western interseismic tectonic deformation field related to plate subduction [26]. In general, previous studies have placed the GPS stations (continuous and episodic ones) at the margin of the SPI, with few discrete observations at the higher SPI plateau. The goal of the present study is to analyze the crustal movements in the northern and higher part of the SPI by GPS continuous measurements during the 2015-2020 period at two locations selected mainly by accessibility (see Figure 1). Due to extreme conditions prevailing in the area, both stations were installed in 2015 on a rigid metal structure fixed to rock outcrops. The first GPS system was called GRCS (Greve Continuous Station), and recorded for a total of 378 days. The second one, named GBCS (Gorra Blanca Continuous Station), registered 911 days in total. Two episodic GPS sites (PUMA and LPAS) located near the front of the Upsala glacier (see station details in Table 1) were also included. For a better validation of the seasonality analyses, two continuous GPS stations called CHLT and VOGH belonging to the International GPS Service (IGS) network were added. Scientific processing of GPS data yielded network station velocities in N, E, and Up, allowing the tendency, seasonality, and other periodic signals of the time series to be examined. The hydrologic system is driven by the loading processes and the transfer of mass from the upper to the lower parts of the SPI basin where the glacial lakes are key natural elements. Consequently, we believe that the trend and seasonality of the observed altimetric GPS signal are related to the water levels of the lakes. For this purpose, we use the gauged lake data of Viedma, O Higgins, and Chico, and the La Leona river. In addition, to analyze the ice loss in the region, we estimated ice elevation changes by differentiation of the Space Shuttle Radar Topography Mission (SRTM) model from February 2000 and altimetric data profiles from the Ice, Cloud, and Land Elevation Satellite (ICESat) mission-1 (2005-2009), and mission-2 (2018-2019). Consequently, the study contributes to the knowledge of the crustal uplift in the northern part of the SPI by using geomatics/remote sensing techniques. Figure 1: Location of GPS stations used in the study in the SPI. The black line in the South American map at Patagonia denotes the asthenospheric window. In red square is represented the study area. The continuous reference GPS stations are indicated in yellow circles. On the right, the map shows the employed ICESat profiles belonging to the SPI subregion considered for spatial filtering (see Section 3.4). The hillshade on which the ICESat profile are mapped were made from the ALOS Global Digital Surface Model (AW3D30, [[https://www.eorc.jaxa.jp/ALOS/en/aw3d30/data/index.htm](https://www.eorc.jaxa.jp/ALOS/en/aw3d30/data/index.htm)]([https://www.eorc.jaxa.jp/ALOS/en/aw3d30/data/index.htm](https://www.eorc.jaxa.jp/ALOS/en/aw3d30/data/index.htm)), accessed on 12 July 2020).