Fatal earthquakes in Türkiye and real-time casualty estimates after the 2011 M7.1 Van earthquake

Türkiye has one of the longest histories of earthquake fatalities dating back to 360 BC. With approximately 1.7 million reported fatalities, it ranks as the worldwide second most earthquake-prone country. The largest contribution to fatalities is made by earthquakes of size 6.0 < M < 7.1. Fatality reports include earthquakes with M < 5 since 1950. The most earthquake fatalities in history per current capita, 10%, have been reported for the East Anatolian Fault Zone (EAFZ), though early historical numbers may be exaggerated. On the same measure, the percentages are: Eastern Türkiye ~ 4%, North Anatolian Fault Zone (NAFZ), western Türkiye ~ 1% each, and 0.01% in central Türkiye. For the M7.1 Van earthquake in 2011, 604 fatalities were estimated correctly by the program Quake Loss Assessment for Response and Mitigation (QLARM), using a line source model for the rupture. For the M7.8 earthquake in 2023 along the EAFZ, a red alert was issued by QLARM within 30 min and in Van within 59 min. The average epicenter separation for the Van earthquake by five estimates was 20 km, which should be reduced because it is a major source of errors in loss calculations when the population is unevenly distributed. The delay in media reports and officially estimated fatalities, and hence the seriousness of a disaster, was unacceptably long after the Van earthquake, taking days to reach half the final estimate. The same was the case for the M7.8 Türkiye-Syria earthquake of February 2023. These delays could be reduced to 5 min. Türkiye ranks second-highest in the world for total reported earthquake fatalities. Most earthquake-induced fatalities in Türkiye are due to events with magnitudes between 6.0 and 7.1. The fatalities from the 2011 Van M7.1 earthquake are accurately estimated with QLARM based on an extended rupture model. Near-real-time fatality estimates remain delayed in Türkiye; improvements could reduce the time of correct disaster assessment to 5 min. Epicenter precision and source inversion models strongly influence near-real-time estimates of fatalities especially in unevenly populated regions.