Synthetic Aperture Radar Interferometry (InSAR) is utilized to evaluate slope stability, revealing pronounced periodic oscillations in the deformation time series. Although such periodic patterns have conventionally been ascribed to stratified tropospheric delays or seasonal precipitation in prior studies, periodic signals persist in the deformation results even after atmospheric phase removal by a linear iterative model. This observation underscores the limitations of conventional deformation interpretations and prompts further investigation into the underlying physical mechanisms. To address this, an interferometric phase correction model accounting for variations in surface dielectric property has been proposed. This model effectively removes phase delays induced by dielectric property changes from the raw interferometric phase, enabling the extraction of linear trend signals that reflect actual surface deformation. To verify the reliability of the correction model, Sentinel-1A (C-band) and TerraSAR-X (X-band) radar data is employed to quantify deformation patterns in the slope of non-sliding section around the Huangnibazi landslide. The analysis consistently identifies periodic deformation signals in both SAR datasets after mitigating atmospheric influences. Our findings indicate that dielectric property changes constitute a critical factor in InSAR deformation monitoring that cannot be overlooked. The observed periodic fluctuations in deformation time series are attributed to dielectric-induced phase modulation effects. Furthermore, systematic correlation analyses confirm a strong coherence between soil moisture variations and deformation fluctuations, with minimal temporal hysteresis. In contrast, seasonal precipitation exhibits a weaker correlation with deformation and longer hysteresis time. These results robustly support the theoretical framework linking soil moisture, dielectric property, penetration depth, and phase delay. This insight holds significant implications for enhancing the effectiveness of InSAR technology in slope disaster monitoring and early warning systems.

On 24 December 2018 a new lateral eruption of Mt. Etna volcano began. The phenomenon produced an intense seismic swarm, strong gaseous emissions from the summit craters and a well-defined lava flow, emplaced on the southwestern portion of the Valle del Bove depression. During the following paroxysm occurred on 29 May 2019, a new lava flow partially covered the previous ones. Aiming to evaluate the effects over time that the emplacement of lava flows produces over the volcanic structure, here we exploited a multidisciplinary approach, comprising both optical (Sentinel-2) and radar (Sentinel-1 and Cosmo-SkyMed) satellite data, processed through different remote sensing techniques. In detail, Sentinel-2 data allowed to retrieve the lava flows boundaries, Sentinel-1 data permitted to reconstruct ground displacement maps and related time series during the January 2016 – July 2021 time span whilst Cosmo-SkyMed ones were used to estimate the topographic changes caused by the lava emplacement.

On 14 November 2021, a doublet earthquake (Mw6.2 and Mw6.3) struck the Fin area in southern Iran. Utilizing the two-pass differential SAR Interferometry (InSAR) method, the coseismic deformation fields, retrieved from 12-day pairs descending and ascending Sentinel-l as well as descending ALOS-2, demonstrate a displacement pattern of maximum 40 cm toward the satellite in the epicentral area. The preliminary slip inversion from the InSAR analysis exhibits best fitting on an east-west trending (∼263°), north-dipping (∼71°) fault as well as an east-west trending (∼84°), south-dipping (∼15°) thrust with a maximum coseismic slip value of ∼2° meters. The south-dipping model shows a better fit and conforms well with the geological setting of the area introduced in the previous studies.

Mt. Etna is one of the world's most active volcanoes and its activity is characterized both by explosive eruptive episodes and by effusive activity. On 24 December 2018 a new lateral eruption of Etna began. The phenomenon was caused by the intrusion of a magmatic dike in the upper eastern flank of the volcano which produced an intense seismic swarm and strong gaseous emissions from the summit craters. In this work Synthetic Aperture Radar (SAR) data acquired from the Sentinel-1 satellite mission were elaborated adopting the Small Baseline Subset technique (SBAS). This multi-temporal method of SAR Interferometry (InSAR) allowed us to obtain the ground displacement map of the area and the deformation evolution of some eruption-induced phenomena, i.e., we tracked the lava flows originated from the opening of eruptive fissures in the western flank of the Valle del Bove depression, and we monitored a paleo-landslide located about 5 kilometers West from the Paternò village, which reactivated during the volcanic unrest.

The rapidly evolving field of open science has made scientists agree on the idea that data, workflows and services, should be findable, accessible, interoperable, and thus optimally reusable. These principles apply to the geohazard community also, dealing with natural phenomena such as volcanic and seismic activity. However, there is still a weakness regarding research sharing and re-use through the scientific community, due to lack of technological solutions and their long-term implementation. We present a lifecycle management service ecosystem based on Research Objects to manage scientific works, in terms of methods, workflows and intermediate or final results, according to open science principles. We show a data cube service for scalable structured data discovery, access and interoperation. These services foster the adoption of remote sensing (e.g., Copernicus) data in the geohazard scientific community enabling research lifecycle documentation. We present test cases of ground deformation analysis and modelling, and volcanic cloud mapping.

Synthetic Aperture RADAR data acquired during several space missions (Envisat, COSMO-SkyMed and Sentinel-1) were treated in order to obtain the ground displacement of the Ischia island (Naples, Italy) and to retrieve the deformation evolution during the investigated time period. The results, validated with available GPS measurements, were found by applying the Small Baseline Subset (SBAS) technique [1], one of the main algorithms proposed in the context of multitemporal methods of Differential SAR Interferometry. This technique permitted to identify and monitor areas affected by slope instability phenomena in a quite continuous time period, from 2002 to the end of 2019. The presented results constitute the basic information for the future application of a GIS-based interdisciplinary approach aimed at the prevention of natural disasters in correspondence with the Ischia island.

Guagua Pichincha (4784 m a.s.1.) is a dacite-composed stratovolcano, located 12 km to the west of Quito, Ecuador's capital with over 2.7 million inhabitants. In the last decades, it was affected by seismic activity. Here, we present the results of multi-temporal InSAR (Interferometric SAR) processing over Guagua Pichincha volcano during 2014-2019, and the related volcanic source modelling. Our results show a general inflation of a restricted area of the volcanic edifice, reaching 2.7 cm/yr deformation rate in the inner caldera and a cumulative uplift of more than 10 cm in 5 years. The resolved ground velocities are better fitted adopting an ellipsoidal shaped tensile crack opening at a depth of 700 m below the domes, with its major axis of about 1 km length in the N36°E direction.

The use of SAR data for imaging hazardous events is nowadays a well-consolidated approach. Thanks to the synoptic capabilities of satellite data, their high spatial resolution and high revisit time, fast and accurate analysis can be performed at both regional and local scale. This work presents the results of SAR Interferometry applied to a multi-hazard event induced by the eruption of Etna volcano, occurred in late December 2018. We analyse both the syn-eruptive deformation of volcano edifice and the effects of an induced Mw4.9 earthquake and a small-scale landslide by exploiting ESA Sentinel-1 data. The data highlight a main horizontal displacement of the Etna summit of more than 40 cm and 65 cm along west and east directions, respectively. The earthquake caused about 15 cm displacement toward east and 20 cm toward west. Finally, approximately 5 cm displacement along satellite Line of Sight was observed associated to the landslide.

We exploit along-track offset estimation techniques applied to Optical and Synthetic Aperture Radar (SAR) data to constrain the co-seismic slip induced by the Mw7.5 earthquake occurred on September, 2018 in Sulawesi island, Indonesia. Such seismic event nucleated along the left-lateral NNW-SSE trending Palu-Koro strike-slip fault and strongly affected Palu Bay causing several effects such as tsunamis and soil liquefactions. Preliminary results show a deformation of more 1.5m along an approximately NS direction both on Optical and SAR data. Moreover, both techniques clearly highlight the surface rupture induced by the earthquake. Further analysis will be focused on accurate comparison and validation of the retrieved results.

In Indonesia land subsidence is occurring in several cities [1], and it is very important to evaluate the spatial and temporal patterns of deformation and investigate the originating processes. In this work, we attempt to define the rates and spatial patterns of subsidence phenomena in Bandung city (Western Java, Indonesia) exploiting InSAR time-series techniques.The Greater Bandung metropolitan area is the second largest urban area in Indonesia, with a population of 8.6 million. The city is built on a plain, 30km in diameter and surrounded by a mountain range of 2000m peaks and it is exposed to a variety of severe geohazards. Floods are common in the lowest part of the plain just south of the city center. Landslides frequently occur on the mountain slopes. Five active volcanoes are within a 30-km radius. Earthquakes, although infrequent, are caused by nearby crustal faults and pose increasing concerns. The risk is also exacerbated due to climate change, fast urban development and land subsidence at an average rate of -8 cm per year.

In this study, multi-frequency Synthetic Aperture Radar Interferometry (InSAR) data are used to constrain the ground deformation due to the August 21st, 2017, Ischia earthquake. InSAR results are the input data to infer the source model of the seismic event. C-band Sentinel-l and X-band COSMO-SkyMed© InSAR results show a displacement pattern in the epicentral area, with a maximum value of ~3.5 cm and a dominant vertical component. Preliminary analytical and numerical models suggest that the retrieved InSAR ground displacements are due to the combination of two phenomena: the tectonic dislocation caused by the slip on the fault plane and the surficial displacement caused by the triggering of shallow landslides.

In this study, an analysis of the November 12, 2017 northwestern Iran earthquake (Mw 7.3) is presented. A multi-frequency Synthetic Aperture Radar Interferometry (InSAR) approach was adopted to retrieve the ground deformation due to the mainshock. Then, InSAR results were used as input for the source modeling of the seismic event. C-Band Sentinel-l (IW TOPSAR acquisition mode) and L-Band ALOS-2 (Wide Swath) SAR data along both the ascending and descending orbits were processed. InSAR results show a displacement pattern in the epicentral area, with a maximum value up to ~1.0 meter. Preliminary analytical and numerical models suggest that the retrieved InSAR ground displacements are due to a slip dislocation (over 3.8 meters) on the causative fault and that dips to the east with a shallow angle of 16°.

We used a variety of SAR-based techniques to measure the crustal deformation associated to the Darfield and Christchurch earthquakes, New Zealand. We detected clear post-seismic signals of the Darfield earthquake, and a pre-seismic signal spatially and temporally associated to the Christchurch earthquake. The small pre-seismic signal (∼25 mm) has an opposite polarity of the much larger co-seismic one (∼150 mm) in the same area.

In this study, we performed a detailed survey of surface deformations occurred in two different regions in Italy. The first, located in Southern Italy, takes into consideration the causative fault of the 1908 Messina earthquake (Mw 7.1), that is an east-dipping normal-oblique fault lying under water along the Straits of Messina. The second site is the L'Aquila area (Central Italy), where a Mw 6.3 earthquake occurred on 6th, April 2009. The subsequent studies demonstrated that the best-fit solution for the main shock, retrieved by DInSAR data, is represented by a normal fault -16 km long and -12 km wide, with a small right-lateral component, dipping 47°SW with a maximum slip of -90 cm (Atzori et al., 2009) [1]. This study is completely carried out within the SiGRiS project, funded by the Italian Space Agency (ASI).

A destructive (Mw 7.9) earthquake affected the Sichuan province (China) on May 12, 2008. The seismic event ruptured approximately 270 km of the Yingxiu-Beichuan fault and about 70 km of the Guanxian-Anxian fault. Surface effects were suffered over a wide epicentral area (about 300 km E-W and 250 km N-S). We apply the differential synthetic aperture radar interferometry (DInSAR) technique to detect and measure the surface displacement field, using a set of ALOS-PALSAR L-band SAR images. We combine an unprecedented high number of data (25 frames from six adjacent tracks) to encompass the entire area which has coseismically displaced. The resulting mosaic of differential interferograms covers an overall area of about 340 km E-W and 240 km N-S. We investigate the source of the Sichuan earthquake by modeling the DInSAR data. The geometry and position of the fault parameters are inferred by a nonlinear inversion, followed by a linear inversion to retrieve the relative slip distribution. Our results show two different source mechanisms for the 145-long Yingxiu-Beichuan fault and for the 105-long Beichuan-Qingchuan fault. Both faults are characterized by slip concentrations of up to 8 m.

SIGRIS (SIstema di osservazione spaziale per la Gestione del RIschio Sismico) is a pilot project aiming to the realization of a system, based on satellite remote sensing data, for the seismic risk management. The project is funded by the Italian Space Agency (ASI). ASI is deeply interested on the development of new applications, using satellite data, dedicated to the monitoring and management of the natural hazards. SIGRIS is focused on providing the information services for mapping, monitoring, forecasting and awareness of seismic risk. The Earth Observation products are generated by using GPS data, optical and SAR (Synthetic Aperture Radar) images. This project deals with the data exploitation of the new Italian Earth Observation mission: COSMO-SkyMed, a constellation of four satellites equipped with an X-band high resolution SAR.