# Scanning Inside Volcanoes with Synthetic Aperture Radar Echography Tomographic Doppler Imaging
## 5 Discussion  
This is the first time that a SAR has been employed to estimate the consistency of depth structures, down to 3 km, considering also that the observations are performed from space. This preliminary work may pave the way for a new type of radar exploitation, where the carrier physical phenomenon is formed by coherent electromagnetic X-band transmissions and azimuth focusing made using ad hoc designed matched filters tuned at the zero Doppler. This procedure can grab phononic (intended to be the vibration of matter) physical parameters. In this context, photons are used as a carrier medium that contains phononic information as well. It seems that this system, although still to be improved and refined, works. This technique can be extended to maybe detect crude oil, or natural gas underground pockets, to quickly search for veins in metals and rare earth, or to assess the consistency of the matter from which all the world's great infrastructures are made. In the present work, we first thought about both nature and humanity preservation, and then found a method (which at present remains unresolved), namely that of looking inside volcanoes with high-resolution imaging from space. It seemed natural to us to focus our research on one of the world's most dangerous volcanoes. It is located in Italy in the middle of the highly populated city of Naples, Vesuvius. In addition, this technique  
Figure 26: Cartographic representation of the seismic events that occurred during the year 2022 at Vesuvius. The pegs represent the position in which one actually occurred in 3D space (latitude–longitude and depth), the radius the magnitude. The red roundels represent those that occurred the month where the SAR acquisition was taken. The magnitude legend has four scales of earthquake in the Richter scale, from the smallest (0 to 1) to the largest (greater than 3).  
allows the construction of an accurate and truthful model of the Earth's subsurface. This possibility appears very important and could serve in helping to strengthen predictive models useful in both the volcanological and seismological fields. According to [34], there is an electromagnetic interaction with the atmosphere. The technique employs the single SAR image, acquired in a time of about 14 s; surely there is an electromagnetic phase delay due to the atmosphere. However, this delay, in practice, does not affect the correct estimation of the tomography, as it is constant in time (this effect is assumed to be time-invariant), so we assume that atmospheric delay remains constant within the SAR acquisition. However, the proposed technique is very robust in terms of compensating for atmospheric interaction as we scan in the Doppler domain, within the single SAR image. To this end, MCA of atmospheric issues is fully described and solved in [28]. Concluding, the proposed technique, can be considered a potential \"gap-filler\", thus allowing us to look inside rigid bodies, like volcanoes, even over high spatial resolution. Authors employed specifically designed software for processing tomographic slices. At the present, there is no commercial software capable of extracting the phonon information embedded in the SAR data. The authors are available in collaborating with other research groups for reproducing the proposed tomographic method specifically, for all those sites that need to be studied in depth.