GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 1.1 - POSTER GNGTS 2023 Fig.1 Example of Earthquake Environmental Effects registered in Mezcala, Michoacán; extensive ground cracks formed along the seashore as a result of lateral spreading and liquefaction processes Data collection is based on 1) field surveys, 2) ex situ data collection via Web and in particular: publications, local sources including online newspapers and government reference sites and social networks (Twitter, Facebook, Instagram, Tik Tok, Youtube), 3) the mapping of landslides from satellite images (3 m resolution PlanetScope satellite imagery). These three approaches can provide independent data with a varying degree of spatial coverage and overall quality in terms of documentation of earthquake damage; the integration of different perspectives allows one to gain a more complete picture of the earthquake effects. Field surveys allowed to obtain high quality data on different types of EEEs, with precise measurements (e.g., crack length and width, dimension of liquefaction sand boils, amount of permanent ground deformation) and photographic documentation, suitable for an accurate evaluation of the intensity. The limitation of this method is related to time constraints and the spatial coverage since high accuracy data can usually be obtained on a limited area. The data collected online are used to overcome this limitation, at least partially: the seismic event was strongly witnessed by the local population and media, providing a large amount of data. The main challenges can be attributed to a greater difficulty in extracting high-quality data and in assigning an accurate location and an appropriate intensity degree.