Fear without a dose-response: real-time crowdsourced psychometrics show a moderate earthquake’s psychological footprint is decoupled from shaking intensity in an anticipation-primed megacity
Year: 2026
Type: preprint
Study design: Observational Study
Abstract: Fear shapes how populations respond to earthquakes, yet it is almost always measured retrospectively, once it cannot be separated from the damage. On 23 April 2025 a MW 6.2 earthquake shook Istanbul – a megacity that has anticipated a major rupture for 25 years – at ground motions below design level, causing one death and light damage. Using a validated earthquake-fear instrument delivered in real time on a crowdsourced platform, we obtained 186 responses within hours, each linked to the respondent’s reported intensity and location. Within the sample, fear barely tracks shaking: its correlation with reported intensity is weak (r = 0.24; 6% of variance), and respondents on Istanbul’s European and Asian sides report indistinguishable fear (24.2 versus 24.5; p = 0.85) despite the European side shaking harder. Fear responds to being substantially shaken at all – a threshold – not to how hard the ground shook – a dose. The footprint was a chronic condition made vivid, not an acute reaction: it produced a behavioural response – 100,000 people outdoors, injuries dominated by panic – out of proportion to a one-fatality event. Real-time psychometric measurement through crowdsourcing is feasible at scale and uniquely separates fear from its physical cause.
DOI: 10.31223/x5kn6h
Language: English
Subfield: Clinical Psychology
Field: Psychology
Domain: Social Sciences
Open Access status: green
Funders: University College London, Fondation MAIF
OpenAlex ID: W7223129999