Editorial. Synthetic aperture radar and natural hazards. Applications and outlooks

The ability of Synthetic Aperture Radar (SAR) to image the Earth’s surface, even through dense cloud cover and in night-and-day conditions, can facilitate the evaluation and monitoring of natural hazards and the management of natural disasters. The family of SAR satellite sensors orbits the Earth at an altitude ranging from 500 to 800 km, following sun-synchronous, near-polar orbits, slightly inclined with respect to Earth meridians. The most commonly used bands in SAR applications are the C-band (5–6 GHz, 5, 6 cm wavelength), the X-band (8–12 GHz, 3, 1 cm wavelength), and the L-band (1–2 GHz 23 cm wavelength) with a temporal resolution depending on the satellite revisiting time. The availability of SAR has made a new spectrum of measurements possible on a global and spatial scale not attainable by ground-based studies, revealing critical insights into remote or poorly understood areas (e.g., Biggs et al., 2014). This Research Topics presents a review of articles on the state-of-art in the application of SAR sensors to study surface deformation in different geologic environments and triggered by a variety of processes. The topics discussed range from the analysis of co-seismic deformation (Merryman Boncori) to studies of volcanic unrest (Dzurisin et al.; Garthwaite et al.), monitoring of landslides (Bianchini et al.) and ground subsidence in urban areas (Solari et al.).