<p>Ground displacements associated to landslides can be analysed by means of geological, geotechnical, topographic and remote sensing techniques. In this work different classical topographic techniques are combined with a satellite based remote sensing technique: Differential SAR Interferometry (DInSAR). The topographic techniques provide precise measurements on a set of points strategically located for each landslide. The DInSAR technique provides a more opportunistic set of points, usually denser than topographic techniques, providing key information on the area of influence of the movement and its potential impact on the surroundings. The combination of both approaches provides a complementary set of measurements useful to properly understand the landslide mechanics. The area of study is Tazones Lighthouse sector (43º 32’ 54’’N, 5º 23’ 57’’W), located on a coastal cliff in north Asturias (N Spain), where there is an important active mass movement.</p><p>The used procedure consisted in the following steps: a) Processing of Envisat ASAR satellite data from 2002 to 2012 to obtain the deformation velocity map of the zone of interest thorough the ESA G-POD service (European Space Agency Grid Processing On Demand); b) Processing of the period 2014-2019 with Sentinel-1 data to obtain the Deformation time series and the deformation velocity map with the PSIG software (developed by the Geomatics Division of the CTTC); c) Integration, combination and comparison by a Geographical Information System (GIS) of the satellite results with topographic data obtained from 2018 to 2019 by means of standard techniques (theodolite, feno survey markers and control points); d) Analysis and interpretation of the results taken into account geological-geomorphological data available.</p><p>The results of this study show different velocity ratios in the Area of Interest (AoI), from mm/year to m/year, which are consistent with the ground measurements. Therefore, the work demonstrated the potentials of combining different geodetic techniques to infer information about landslides processes and the usefulness of the DInSAR for the control of the mass movement, whose fast evolution makes it difficult the topographic work due to the changes in the relief and the loss of several feno survey markers.</p>

<p>The Tazones Lighthouse landslide is an active mass movement affecting a stretch of the Cantabrian Coast (N Spain), characterized by the presence of almost vertical rocky cliffs developed on Jurassic rocks. The area is being monitored since 2018 when irreversible structural damages appeared in a building located in the surroundings of the lighthouse because of the fast evolution of the landslide.</p><p> </p><p>On June 2018, the first 24 topographic marks were installed by the COSINES Project researchers and 10 more were set up on December of that year, after the appearance of new cracks. Since then, monthly monitoring campaigns have been carried out by total station to gauge the displacement of the 34 mentioned marks and 4 additional control points. One of the control marks was lost, between January and February 2019, due to the fast evolution of the movement. Monitoring has been complemented by the elaboration of detailed digital terrain models through drone flights carried out in November 2018 and November 2019. In addition, precipitation data registered on the rainfall gauges of the surroundings have been collected.</p><p> </p><p>This contribution presents the recent fast evolution of the Tazones Lighthouse landslide, affecting an area about 70.000 m<sup>2</sup> and characterized by relevant horizontal and vertical displacements. Since the beginning of the 3D monitoring, the 50% of the marks have moved more than 1 meter and 34% of them have moved more than 2 meters, one of them exceeding 14 meters of displacement.</p><p>The detailed digital terrain models have allowed quantifying the volume of mobilized mass over a year from the main head of the movement, located 110 meters above sea level. Moreover, the comparison of these data with precipitation records has led to relate the evolution of the displacement with the rainfall, being able to establish a very good correlation between precipitation distribution and movement acceleration.</p>

ResumenSe presentan en estas p6ginas 10s objetivos, 10s planteamientos metodologicos y 10s primeros resultados del "Proyecto Veranes", yacin.liento tardorromano y medieval situado en las proximidades de la ciudad de Gijdn. Dicho proyecto, financiado mayoritariamente por el Ilmo. Ayuntamiento de Gijdn, es el fruto de un esfuem coordinado entre diversas instituciones pdblicas. SummaryIn this paper we present the aims, the methodological proposals and the first results of Veranes Project, a Late-Roman and Medieval archaeological site near the city of Gijbn. The main part of this project is financed by Gijdn City Council and also constitutes the effort among different public institutions.

Abstract. The Tazones Lighthouse slope shows different active mass movements affecting an area of 70.000 m2 of the Cantabrian Coast (N Spain), characterized by almost vertical rocky cliffs developed on Jurassic rocks: alternating marl, sandstone and limestone with three main stratigraphic and structural discontinuity families. Between June 2018 and May 2020, 22 monthly monitoring campaigns have been carried out to measure the displacement of 38 control points, located between 95–110 masl. The total station monitoring has been complemented by ortophoto analysis and detailed digital terrain models (DTM) from two drone flights. Since the beginning of the 3D monitoring, about the 50 % of the markers moved more than 1 m, one of them exceeding 15 m. Detailed DTM has shown that the increased activity is controlled by the discontinuities. There is an extraordinary correlation between displacement acceleration and precipitation and soil moisture: the largest displacements have occurred after 2 periods of intense rain (January and October–November 2019, with a maximum 24-hour precipitation of 64.5 mm and 82.1 mm, respectively, and soil moisture values higher than 90 %). This represents an exceptional opportunity to analyse in real time the Jurassic cliffs retreat of the Cantabrian Coast, a question that remained not quantified.