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Landslides are widespread natural hazards that generate considerable damage and economic losses worldwide. Detecting terrain movements caused by these phenomena and characterizing affected urban areas is critical to reduce their impact. Here we present a fast and simple methodology to create maps of vulnerable buildings affected by slow-moving landslides, based on two parameters: (1) the deformation rate associated to each building, measured from Sentinel-1 SAR data, and (2) the building damage generated by the landslide movement and recorded during a field campaign. We apply this method to Arcos de la Frontera, a monumental town in South Spain affected by a slow-moving landslide that has caused severe damage to buildings, forcing the evacuation of some of them. Our results show that maximum deformation rates of 4 cm/year in the line-of-sight (LOS) of the satellite, affects La Verbena, a newly-developed area, and displacements are mostly horizontal, as expected for a planar-landslide. Our building damage assessment reveals that most of the building blocks in La Verbena present moderate to severe damages. According to our vulnerability scale, 93% of the building blocks analysed present high vulnerability and, thus, should be the focus of more in-depth local studies to evaluate the serviceability of buildings, prior to adopting the necessary mitigation measures to reduce or cope with the negative consequences of this landslide. This methodology can be applied to slow-moving landslides worldwide thanks to the global availability of Sentinel-1 SAR data. [ABSTRACT FROM AUTHOR]

The launch of the medium resolution Synthetic Aperture Radar (SAR) Sentinel-1 constellation in 2014 has allowed public and private organizations to introduce SAR interferometry (InSAR) products as a valuable option in their monitoring systems. The massive stacks of displacement data resulting from the processing of large C-B and radar images can be used to highlight temporal and spatial deformation anomalies, and their detailed analysis and postprocessing to generate operative products for final users. In this work, the wide-area mapping capability of Sentinel-1 was used in synergy with the COSMO-SkyMed high resolution SAR data to characterize ground subsidence affecting the urban fabric of the city of Pistoia (Tuscany Region, central Italy). Line of sight velocities were decomposed on vertical and E–W components, observing slight horizontal movements towards the center of the subsidence area. Vertical displacements and damage field surveys allowed for the calculation of the probability of damage depending on the displacement velocity by means of fragility curves. Finally, these data were translated to damage probability and potential loss maps. These products are useful for urban planning and geohazard management, focusing on the identification of the most hazardous areas on which to concentrate efforts and resources. [ABSTRACT FROM AUTHOR]

It has long been recognized that earthquakes change the stress in the upper crust around the fault rupture and can influence the behaviour of neighbouring faults and volcanoes. Rapid estimates of these stress changes can provide the authorities managing the post-disaster situation with valuable data to identify and monitor potential threads and to update the estimates of seismic and volcanic hazard in a region. Here we propose a methodology to evaluate the potential influence of an earthquake on nearby faults and volcanoes and create easy-to-understand maps for decision-making support after large earthquakes. We apply this methodology to the Mw 7.8, 2016 Ecuador earthquake. Using Sentinel-1 Interferometric Synthetic Aperture Radar (InSAR) and continuous GPS data, we measure the coseismic ground deformation and estimate the distribution of slip over the fault rupture. We also build an alternative source model using the Global Centroid Moment Tensor (CMT) solution. Then we use these models to evaluate changes of static stress on the surrounding faults and volcanoes and produce maps of potentially activated faults and volcanoes. We found, in general, good agreement between our maps and the seismic and volcanic events that occurred after the Pedernales earthquake. We discuss the potential and limitations of the methodology. [ABSTRACT FROM AUTHOR]

Persistent Scatterer Interferometry (PSI) is a consolidated tool for detecting and monitoring ground surface displacements. The availability of satellite data with free access policy and high monitoring capabilities (in terms of resolution and acquisition frequency) is increasing. Moreover, the first continental displacement map of Europe will be freely available in quarter one 2022 by the latest Copernicus Service, the European Ground Motion Service (EGMS). The EGMS will provide ground displacement maps, updated every year, delivering valuable information to a wide range of users, such as public or governmental institutions, industry, academia, and citizens. This vast amount of information needs semi-automatic tools and methodologies to derive user-oriented products that can be easily used by land use and urban planning decision-makers, who are often unfamiliar with PSI. This work proposes a semi-automatic procedure to identify damage prone areas in urban environments from wide-area PSI displacement maps. The proposed method identifies the most significant Active Deformation Areas (ADAs) to calculate three products based on the displacement intensity gradient: the Gradient Intensity Map, the Gradient Vectors and Time Series, and the Potential Damage Map. These products allow identifying buildings and urban structures exposed to potential damage, which could be followed by a more detailed building-based vulnerability and risk assessment. The methodology has been applied to an area of the province of Granada (Andalucía, Spain) but it can be applied to any other urban environment where PSI displacement maps are available. To demonstrate the advantages and limitations of the proposed method, results are discussed in five coastal resorts (Cerro Gordo, Punta de la Mona, Marina del Este, Alfa Mar, and Monte de los Almendros), strongly affected by slope movements. The methodology allowed to derive 175 ADAs from about 200,000 measurement points. About 15% of the resulting area has been found to correspond to high or very high gradient intensity class, and 192 out of 633 buildings have been identified to be prone to moderate or high potential damage. A damage prediction test has been realized through Receiver Operating Characteristic (ROC) analysis, based on a damage inventory map derived from field surveys. The results demonstrate the effectiveness of the methodology to localize damaged or potentially damaged buildings, substantially reducing the time of analysis. • A step towards the automatic exploitation of satellite interferometric (InSAR) data. • Automatic exploitation of PSI to support a multi-scale geohazard risk management. • A methodology for the automatic exploitation of EGMS continental displacement maps. • Potential Damage Maps based on spatial gradients of velocity and angular distortion. • Regional scale detection of coastal landsides causing damages in Granada Region. [ABSTRACT FROM AUTHOR]

This work integrates detailed geological and hydrogeological information with PSI data to obtain a better understanding of subsidence processes detected in the detrital aquifer of the Vega de Granada (SE Spain) during the past 13 years. Ground motion was monitored by exploiting SAR images from the ENVISAT (2003–2009), Cosmo-SkyMed (2011–2014) and Sentinel-1A (2015–2016) satellites. PSInSAR results show an inelastic deformation in the aquifer and small land surface displacements (up to −55 mm). The most widespread land subsidence is detected during the ENVISAT period (2003–2009), which coincided with a long, dry period in the region. The highest displacement rates recorded during this period (up to 10 mm/yr) were detected in the central part of the aquifer, where many villages are located. For this period, there is a good correlation between groundwater level depletion and the augmentation of the average subsidence velocity and slight hydraulic head changes (<2 m) have a rapid ground motion response. The Cosmo-SkyMed period (2011–2014) coincided with a rainy period, and the land subsidence is only concentrated in some points. Rates of average subsidence up to 11.5 mm/yr are obtained for this period and are anthropogenic in origin, being related to earthmoving works. During the Sentinel-1A monitoring period (2015–2016) most of the region showed no deformation, except for some points of unknown origin in the NE sector. A general conclusion is that there is a clear lithological control in the spatial distribution of ground subsidence; all the subsiding areas detected are located where a higher clay content was identified. Although the SE sector of the aquifer had more intense groundwater exploitation, no land subsidence processes were detected, as coarse-grained sediments predominate in the substratum. This research will contribute to the drawing-up of a management plan for the sustainable use of this strategic aquifer, taking into account critical levels of groundwater depletion to avoid land subsidence in the areas identified as vulnerable. The European Space Agency satellite Sentinel-1A could be an effective decision-making tool in the near future. [ABSTRACT FROM AUTHOR]