## 2 Materials and Methods  
### Field Mapping  
The high-resolution mapping of the surface coseismic ruptures in the field was carried out integrating the traditional survey, performed using a geologic compass-clinometer for measurement of planar and linear elements (dip azimuth/ dip-angle of fault planes, trend and plunge of slickenlines), with digital mapping technique. The digital mapping was based on a digital compass-clinometer App  
Figure 3: (**a–d**): Sample area 1—the same outcrop of the CAB fault scarp shooted at three temporal stages: (**a**) before the beginning of the 2016 seismic sequence, (**b**) after the 24 August and 26 October events but before the 30 October one, and (**c,d**) after the 30 October mainshock (bottom left on each image, date and the hour of photo shooting); (**e–h**): sample area 2—images at different scales, of the coseismic surface effects of the 30 October mainshock along the PTP fault trace.  
for portable devices, allowing the direct measurement of georeferenced planar and linear elements accompanied by written notes, sketches, and editable photographs of each survey site (Figure 4). The \"Fieldmove\" App for smartphones, tablets, and iPad, developed by Midland Valley & Petroleum Experts [42], Glasgow-Edinburgh Scotland, was chosen and installed on an Apple iPad Air2 wifi-cellular (128 GB memory) with an internal A-GPS GLONASS/GNSS.  
Several preliminary trials allowed to verify that the internal sensor of IOS provides reliable and precise azimuthal and dip-angle measures. The reliability-trials consisted of repeated comparisons between measures of the same structure carried out using the digital device and the geological compass-clinometer. This testing experience highlighted that the chosen device and software assured accurate compass readings for both azimuthal and clinometric measurements that not exceed \(\pm 2\) degrees. For the positioning of the elements measured, an internal sensor A-GPS and GLONASS/GNSS also integrated with the high-resolution images from the Google Earth(tm) Pro 7.3 was successfully used. The accuracy of the waypoints acquired depended on satellite coverage. When the maximum satellite coverage reached the optimum values, the error estimated for the automatic location was of 1-2 m, whereas it reached 3-5 m in the worst coverage conditions. The solution to minimalize the error location (well below one-meter resolution) was the manual adjusting on the iPad screen, taking into account the easily recognizable elements on the Google Earth base map imagery. A further precaution to avoid positioning inaccuracies was the use, as Fieldmove base maps, of previously acquired high-resolution images, orthorectified through ArcGis, and exported from the Move software in mbtiles or geotiff format file.  
Field data were organized in a comprehensive GIS-managed dataset for subsequent elaborations. The used software aside from the Fieldmove App for Apple iPad includes Esri ArcMap 10.x and Move 2019 Petex suite [[[http://www.petex.com/products/move-suite/](http://www.petex.com/products/move-suite/)]([http://www.petex.com/products/move-suite/](http://www.petex.com/products/move-suite/))]. All the geological-structural data acquired were elaborated within the Move suite software Petroleum Experts see Section 3.1.2.  
Figure 4: Survey tools used during different fieldwork activities: above: Traditional compass-clinometer and Digital device (Apple iPad Air2) supporting the “Fieldmove” App by Midland Valley & Petroleum Expert, in position for the measurement of a shear plane within a fault breccia; below: Drone model DJI Phantom 3 Professional and details of its components; Sony camera DSC-HX5V with integrated GPS; bottom-right: traditional papery field book.