Testing a logic tree approach for archaeoseismology to the ancient city of Pınara (SW Turkey)

Geologists, seismologists, as well as archaeologists increasingly apply archaeoseismological investigations to study possible natural causes of damage of a site and to assess the regional seismic hazard risks. Archaeoseismological investigations enable the obtaining of diverse data on past earthquakes and allow for an application of different methods. Furthermore, archaeoseismology provides the opportunity to study past earthquakes in regions where limited instrumental and historical data are available. Therefore, this approach contributes to a regional assessment of seismic hazard. The increasing application and importance of archaeoseismology requires a comprehensive and systematic approach. The logic tree methodology for archaeoseismology is an evaluation method which offers a standard procedure to identify and evaluate archaeoseismological information and to provide comparable values for seismic hazard assessment. This study tests the logic tree methodology for archaeoseismology to Pınara to assess the city’s potential to have recorded earthquakes, and the methodology’s value. The ancient city of Pınara (SW Turkey, 500 BC–900 AD) is situated in the Eşen basin in the southern extremity of the seismically active Fethiye-Burdur fault zone. The present seismic quiescence of the Eşen basin contradicts the geological and historical records which indicate that fault and earthquake activity must have been recurrent. With the application of the logic tree approach to Pınara, geological and archaeoseismological evidence of seismic activity is evaluated in six stages. The end solution of the logic tree provides a value between 0 and 1. This archaeological quality factor (AQF) reflects the reliability and relative significance of Pınara for archaeoseismological investigation and seismic hazard assessment respectively. Pınara’s preferred end solution (Pes1) of 0.06 and the AQF of 0.12 are obtained by the logic tree method and reflect the high probability of recorded palaeoearthquakes in Pınara. In sum, the logic tree for archaeoseismology provides a concept with reliable criteria to assess the earthquake hypothesis in general, and the findings suggest the assumed low seismic hazard potential of this area needs serious reconsideration.