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
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.
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BibTeX
@misc{aktas2026fear,
title = {{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}},
author = {Yasemin Didem Aktas and Remy Bossu and Simon Issartel and Robert Steed},
howpublished = {EarthArXiv},
year = {2026},
month = oct,
doi = {10.31223/x5kn6h},
url = {https://eartharxiv.org/repository/view/15622/},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - 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
AU - Yasemin Didem Aktas
AU - Remy Bossu
AU - Simon Issartel
AU - Robert Steed
PY - 2026
DA - 2026/10/21
PB - EarthArXiv
DO - 10.31223/x5kn6h
UR - https://eartharxiv.org/repository/view/15622/
AB - 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.
ER -