HSIT system: Citizen Participation in Seismology for Data Collection and Enhanced Understanding of Earthquake Effects

Hai Sentito Il Terremoto (HSIT: Did You Feel the Earthquake?) is one of the longest-running citizen science projects on the web. Launched experimentally in 1996 and fully operational since 2007, HSIT has collected data on over 16,800 earthquakes felt in Italy through more than 1,500,000 questionnaires submitted by citizens. Of these, nearly 30,000 participants are registered with HSIT, ensuring continuous engagement across the national territory. The results of this collaboration are bidirectional: citizens contribute their experience of earthquake perception, forming a core dataset that provides localized information. In return, they receive real-time feedback on the earthquake's effects on their region, represented in macroseismic intensity using the Mercalli (MCS) and European (EMS) scales. This partnership enables seismologists to access high-resolution data for analyzing territorial responses to seismic events, including attenuation laws, identifying amplification and/or attenuation zones, and perception patterns based on urban characteristics and behavioral factors. Citizen involvement has expanded the scope of the investigation to include moderate-to-low magnitude earthquakes and distant areas affected by stronger quakes. Registered participants, in particular, gain awareness of earthquakes as ongoing, active phenomena, shifting from a perception of rare catastrophic events to a continuous focus on regional seismic risks. The HSIT project bridges the gap between scientific knowledge and common understanding, fostering a shared experience of living in earthquake-prone regions with awareness and respect for associated risks and preventive measures.