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We collected drone data to quantify the kinematics at extensional fractures and normal faults, integrated this information with seismological data to reconstruct the stress field, and critically compared the results with previous fieldwork to assess the best practice. As a key site, we analyzed a sector of the northeast rift of Mt Etna, an area affected by continuous ground deformation linked to gravity sliding of the volcano's eastern flank and dike injections. The studied sector is characterized also by the existence of eruptive craters and fissures and lava flows. This work shows that this rift segment is affected by a series of NNE- to NE-striking, parallel extensional fractures characterized by an opening mode along an average N105.7∘ vector. The stress field is characterized by a σHmin trending northwest–southeast. Normal faults strike parallel to the extensional fractures. The extensional strain obtained by cumulating the net offset at extensional fractures with the fault heave gives a stretching ratio of 1.003 in the northeastern part of the study area and 1.005 in the southwestern part. Given a maximum age of 1614 CE for the offset lavas, we obtained an extension rate of 1.9 cm yr−1 for the last 406 years. This value is consistent with the slip along the Pernicana Fault system, confirming that the NE rift structures accommodate the sliding of the eastern flank of the volcano.

We document and show a state-of-the-art methodology that could allow geoheritage sites (geosites) to become accessible to scientific and non-scientific audiences through immersive and non-immersive virtual reality applications. This is achieved through a dedicated WebGIS platform, particularly handy in communicating geoscience during the COVID-19 era. For this application, we selected nine volcanic outcrops in Santorini, Greece. The latter are mainly associated with several geological processes (e.g., dyking, explosive, and effusive eruptions). In particular, they have been associated with the famous Late Bronze Age (LBA) eruption, which made them ideal for geoheritage popularization objectives since they combine scientific and educational purposes with geotourism applications. Initially, we transformed these stunning volcanological outcrops into geospatial models—the so called virtual outcrops (VOs) here defined as virtual geosites (VGs)—through UAV-based photogrammetry and 3D modeling. In the next step, we uploaded them on an online platform that is fully accessible for Earth science teaching and communication. The nine VGs are currently accessible on a PC, a smartphone, or a tablet. Each one includes a detailed description and plenty of annotations available for the viewers during 3D exploration. We hope this work will be regarded as a forward model application for Earth sciences’ popularization and make geoheritage open to the scientific community and the lay public.

In the present work we applied the use of the UAV-based Structure from Motion technique (SfM) to geological and geohazard studies, with emphasis placed on active tectonics and volcano-tectonics cases. Our aim is to obtain high-resolution orthomosaics and Digital Surface Models (DSMs) in two study areas: the Theistareykir Fissure Swarm within the Northern Volcanic Zone (NVZ) of Iceland and the active Khoko landslide, Enguri reservoir, in the Greater Caucasus, Georgia. The first is affected by seismic and volcanic hazard, the second by landslide and hydrogeological hazard. Regarding the NVZ, by analysing the resulting Orthomosaics and DSMs we collected a total of 453 quantitative measurements of the amount of opening and opening direction of Holocene extension fractures and 36 measurements of the height of fault scarps. These data allowed us to assess an overall spreading direction of N106.4° during Holocene times within the studied rift zone, which has been compared with geodetic motion vectors, and a stretching ratio of 1.013–1.017 for 8–10ka old lava units. We conclude that deformation in the area is related to both dyke intrusions and extensional tectonics. In the Greater Caucasus, we applied the method to identify the main geomorphological features related to the Khoko landslide and to measure the scarp height of the principal slip surfaces, in order to improve geomorphological knowledge of the landslide, and contribute to the assessment of the hydrogeological hazard of the area. At a general level, our results suggest that the use of UAV-based SfM is a convenient and efficient way to collect plenty of data aimed at better assessing geohazards in areas prone to catastrophic natural phenomena like earthquakes, volcanic eruptions and landslides.

In the present work, we test the application of boat-camera-based photogrammetry as a tool for Virtual Outcrops (VOs) building on geological mapping and data collection. We used a 20 MPX camera run by an operator who collected pictures almost continuously, keeping the camera parallel to the ground and opposite to the target during a boat survey. Our selected target was the northern part of Santorini's caldera wall, a structure of great geological interest. A total of 887 pictures were collected along a 5.5-km-long section along an almost vertical caldera outcrop. The survey was performed at a constant boat speed of about 4 m/s and a coastal approaching range of 35.8 to 296.5m. Using the Structure from Motion technique we: i) produced a successful and high-resolution 3D model of the studied area, ii) designed high-resolution VOs for two selected caldera sections, iii) investigated the regional geology, iv) collected qualitative and quantitative structural data along the vertical caldera cliff, and v) provided a new VO building approach in extreme logistic conditions.

In the present work, we applied the use of an Unmanned Aerial Vehicle (UAV) - a quadcopter - and the Aerial Structure from Motion digital photogrammetry image processing technique (ASfM) to study volcano-tectonics and tectonic features in an active Icelandic rift. Data have been collected in order to evaluate the Holocene deformation in the Northern Volcanic Zone of Iceland. We mapped 397 structures, mainly related to extension fractures and subordinately normal faults in the Theistareykir Fissure Swarm, obtaining 1098 and 21 structural data, respectively. This allowed to reconstruct an overall spreading direction of N108° during Holocene times, and to calculate a stretch of 1.013 regarding 8–10 ka old lava units. Deformation in the area is related to both dyke intrusions and extensional tectonics. Furthermore, detailed geological-structural field and UAV surveys were also performed in two test areas in order to determine data accuracy and the associated reliability of this approach. In addition to the above, different flight heights were tested, suggesting that photo collection with a 12.4 MPx camera at 100 m is efficient to study fracture dilation and kinematics.

In the present work, we have obtained a detailed, complete view of surface deformation at a volcano-tectonic structure belonging to the Krafla Fissure Swarm (NE Iceland), through the integration of field mapping and the Aerial Structure from Motion technique (ASfM), as well as through orthomosaics and Digital Surface Models (DSMs). The documented, 2.5-km-long deformation zone is marked by a range of features, such as topographic bulging, parallel extension fractures, and narrow grabens affected by local floor uplift, which we have explained as the effect of the northward, shallow propagation of a dyke from the Krafla magma chamber. Our lithostratigraphic field survey of the area, at a 1: 5000 scale, indicates that major changes in the pattern of surface deformation take place across the contacts between deposits with different rheological properties. The transition from very stiff lavas to softer hyaloclastites produces changes from extensional fracturing to normal faulting, though the width of the deformation zone does not change. We have also documented a number of NE-SW, left-lateral and NNW-SSE, right-lateral strike-slip fault zones that are rotated in clockwise and anticlockwise sense to the main NNE-SSW graben trend, and extend outwards as much as about 17 m. The graben zone terminates to the north by splitting into two strike-slip fault zones. These were likely generated at the front of the dyke tip during its propagation, and were later on bypassed by the advancement of the dyke. As the dyke entered the soft hyaloclastites, propagation was slowed down and the dyke became thicker.

This paper presents a novel immersive Virtual Reality platform, named ARGO3D, tailored for improving research and teaching activities in Earth Sciences. The platform facilitates the exploration of geological environments and the assessment of geo-hazards, allowing reaching key sites of interest (some of them impossible to be reached in person) and thus to take measurements and collect data as it can be done in the real field. The target audience of ARGO3D encompasses students, teachers and early career scientists, as well as civil planning organisations and non-academics. The overall workflow for real ambient reconstruction, processing and rendering of the virtual ambient is presented, as well as a detailed description of the VR software tools and hardware devices employed.