  The effects on structures of the earthquake with magnitude 7.8 on the Richter
scale (moment magnitude scale) which took place in Pazarcik, Kahramanmaras,
Turkiye at 04:17 a.m. local time (01:17 UTC) on February 6, 2023, are
investigated by processing suitable seismic records using the open-source
software OpenSeismoMatlab. The earthquake had a maximum Mercalli intensity of
XI (Extreme) and it was followed by a Mw 7.5 earthquake nine hours later,
centered 95 km to the north-northeast from the first. Peak and cumulative
seismic measures as well as elastic response spectra, constant ductility (or
isoductile) response spectra, and incremental dynamic analysis curves were
calculated for two representative earthquake records of the main event.
Furthermore, the acceleration response spectra of a large set of records were
compared to the acceleration design spectrum of the Turkish seismic code. Based
on the study, it is concluded that the structures were overloaded far beyond
their normal design levels. This, in combination with considerable vertical
seismic components, was a contributing factor towards the collapse of many
buildings in the region. Modifications of the Turkish seismic code are required
so that higher spectral acceleration values can be prescribed, especially in
earthquake-prone regions.
