# Review of Works Combining GNSS and InSAR in Europe
## 3 Temporal and Spatial Distribution of Scientific Production in Europe
### Field of Application
Other interesting research in the field of tectonism utilized earthquake observations with remote sensing data from the M\({}_{\rm w}\) 6.4 Durres (Albarnia) earthquake that occurred in 2019 [155] and the M\({}_{\rm w}\) 6.5 Lorca earthquake (Spain) [56]. Studies on seismic [156] and crustal deformation [157], sometimes connected to strain rate analysis [66], or interactions with volcanic systems [68; 69], connected to earthquake seismic swarms or active tectonic faults, are more common. Volcanic (10.9%) applications are mainly concentrated in (i) Greece, focused on the investigation of Santorini volcano [158; 159] and Nisyros volcano [83; 86]; (ii) Italy, focused on the evaluation of the deformation of Mt. Etna, Sicily Region (Southern Italy) [160; 161] and the Campi Flegrei, Campania Region (Southern Italy) [40; 51]; (iii) Portugal, focused on the assessment of the geodynamics and displacement mechanisms affecting the Azores islands [13; 14; 69]; and (iv) Spain [55], focused on the volcanic deformation of the Canary archipelago [58] and Tenerife island [24; 57; 162; 163], inevitably depending on the presence of active volcanoes. Iceland is represented by two scientific articles, one focusing on the lateral dyke grown [72] and the gradual caldera collapse regulated by lateral magma overflow [25] of the Bardarbunga stratovolcano in the South-eastern sector of the Iceland island; and a conference paper combining InSAR and GNSS data [74] that focuses on ground deformation measurements of the Northern Volcanic Zone of the island. In addition, [PERSON] et al. [17] published an article on Mt. Etna focused on the measurement of the tropospheric water value to better consider the contribution of the atmosphere to the differential radar interferograms of ERS1/2. Atmosphere applications (10.4%), unlike subsidence, landslide activity, and tectonic and volcanic phenomena, generally involve wide areas, ranging from regional to national scales. Atmospheric applications of the combination of GNSS and SAR data encompass the field of water vapor determination [164; 165; 166; 167; 168; 169], atmospheric model or delay analysis [17; 17; 18; 31; 38; 170], ionospheric artifacts detection [171], atmospheric and wet refractivity reconstruction [65; 172] and tropospheric correction or delay [77; 173; 174; 175], with the final goal of assessing a more precise atmospheric correction in ground deformation analysis of SAR datasets in wide areas or peculiar zones, e.g., volcanic. The Subsidence/Uplift class (4.4%) includes surface deformation analyses performed at a large, regional or national scale, in which both subsidence and uplift phenomena can be identified. Case studies were identified in Netherlands, such as surface deformation analyses performed over the whole national territory [176; 177; 178] or monitoring works of the water defence structure of Waddenzee and IJsselmeer [180; 181]. Two other scientific contributions focused on the Polish and Lithuanian Baltic coastal areas [105] and the surface displacement pattern affecting the permafrost areas in northern Norway [75]. The categories of Uplift, Infrastructure, and Glacial are poorly represented. In fact, three peer-reviewed articles, focused on the Tower Hamlets Council area of London [182] and on the Geothermal site Landau in Germany [19; 63], which only investigated uplift phenomena resulting from the swelling of clayey soil and geothermal consequences, respectively, can be cited. The lower number of studies focused on the investigation of infrastructure can be attributed to several factors, e.g., the resolution of SAR images, the distribution of the GNSS network compared to the infrastructure dimensions, the particularity of the application and the difficulty associated with interpreting the results. An investigation of the nonlinear deformation of infrastructure via SAR data and GNSS comparison was performed in Bratislava, Slovakia [26].