Local Seismic Response (LSR) studies are considerably conditioned by the seismic input features due to the non-linear soil behavior under dynamic loading and the sub-surface site conditions (e.g., mechanical properties of soils and rocks and geological setting) [1][2]. The selection of the most suitable seismic input is a key point in LSR. Unfortunately, a few natural recordings are available at seismic stations in near field areas [3][4]. Then, synthetic accelerograms can be helpful in LSR analysis in urbanized near field territories. Synthetic accelerograms are generated by simulation procedures that consider adequately supported hypotheses about the source mechanism at the seismotectonic region and the wave propagation path towards the surface. Hereafter, mainshocks recorded accelerograms at near field seismic stations during the 2016-17 Central Italy seismic sequence have been compared with synthetic accelerograms calculated by EXSIM code [5] [6]. The outcomes show that synthetic signals can reproduce the high-frequency content of seismic waves at near field areas. Then, in urbanized near field areas, synthetic accelerograms can be fruitfully used in Microzonation studies. References [1] Vessia G. et al. (2013), Bull. Earthq. Eng., 11(5), 1633-1660. [2] Vessia G. et al. (2021), Eng. Geol. 284, 106031. [3] Mancini F. et al. (2018), ESC2018, S29-639: 428429. [4] Luzi L. et al. (2016), Istituto Nazionale di Geofisica e Vulcanologia, Observatories & Research Facilities for European Seismology. [5] Boore D. M. (2003), Pure Appl. Geophys. 160 635–675. [6] Motazedian D. and Atkinson G. M. (2005), Bull. Seismol. Soc. Am. 95 995–1010.

Virtual reality (VR) is an important tool for several applications in science, industry, and education. Previous studies have already shown how the use of VR at full scale is an effective tool for outcrops characterization even at centimetre scale [1]. We aim to extend the use of this approach in various fields of planetary exploration, from outcrop to regional scale. This regional approach may provide an effective support for the planning and management of future missions, but also for geological and geomorphological studies and mapping. Among the most obvious advantages of the use of virtual reality are the lack of optical deformations and approximate dimensions of the two-dimensional display (such as display, projections and printed cartography) and the opportunity to layer various levels of information through a new concept of superposition. The VR environment is derived from several multi-scale elements: medium to high-resolution elevation data, photogrammetric 3D models, orthophotos, multispectral data, thematic maps and vector data transformed into three-dimensional digital representations placed in the study context. The first tests are based on stereogrammetry (using USGS ISIS [2] and NASA ASP [3]) of the lunar LRO (LROC-NAC) [4] and Martian MRO (CTX and HiRISE) [5] and MEX (HRSC) [6] missions and on data and cartography realized through external open-source GIS tools (GDAL libraries, QGIS, GRASS) and virtual tools developed to be used within the VR environment. In our tests, for example, the Rock Abundance analysis results have been shown not only as thematic maps but also as digital representations of floating boulders on the surface. This has been achieved by placing major rock elements (>1m) in the position detected from satellite imagery and smaller elements, estimated from size-frequency distributions studies, with a preliminary semi-random distribution. References [1] Mouélic S. L. et al. (2019), Geophys. Res. Abstr, Vol. 21. [2] Becker K. J. et al. (2013), LPSC, Vol. 44. [3] Moratto Z. M. et al. (2010), LPSC, No. 1533, p. 2364. [4] Robinson M. S. et al. (2010), Space Sci. Rev., 150: 81-124. [5] McEwen A. S. et al. (2007), J. Geophys. Res. Planets, 112.E5 [6] Neukum G. & Jaumann R. (2004). Mars Express: The Scientific Payload, Vol. 1240, pp. 17-35.