Revelations from a single strong-motion record retrieved during the 27 June 1998 Adana (Turkey) earthquake

During the 27 June 1998 Adana (Turkey) earthquake, only one strong-motion r ecord was retrieved in the region where the most damage occurred. This sing le record from the station in Ceyhan, approximately 15 km from the epicente r of that earthquake, exhibits characteristics that are related to the domi nant frequencies of the ground and structures. The purpose of this paper is to explain the causes of the damage as inferre d from both field observations and the characteristics of a single strong-m otion record retrieved from the immediate epicentral area. In the town of C eyhan there was considerable but selective damage to a significant number o f mid-rise (7-12 stories high) buildings. The strong-motion record exhibits dominant frequencies that are typically similar for the mid-rise building structures. This is further supported by spectral ratios derived using Naka mura's method [QR of RTRI, 30 (1989) 25] that facilitates computation of a spectral ratio from a single tri-axial record as the ratio of amplitude spe ctrum of horizontal component to that of the vertical component [R = H(f)/V (f)]. The correlation between the damage and the characteristics exhibited from the single strong-motion record is remarkable. Although deficient construction practices played a significant role in the extent of damage to the mid-rise buildings, it is clear that sire resonance also contributed to the detrimental fate of most of the mid-rise buildings . Therefore, even a single record can be useful to explain the effect of si te resonance on building response and performance. Such information can be very useful for developing zonation criteria in similar alluvial valleys. P ublished by Elsevier Science Ltd.