Historical earthquakes that damaged Hierapolis and Laodikeia antique cities and their implications for earthquake potential of Denizli basin in western Turkey

Abstract

Denizli basin is situated at the junction of NW– SE trending Gediz Graben and E–W trending Bu¨yu¨k Menderes Graben in the eastern part of the western Anadolu (Anatolian) extensional province in western Turkey, which has been home to many civilizations during its long history and therefore has ruins of many antique cities and settlements. Most of antique cities were destroyed by strong earthquakes that occurred in ancient times. Strong historical earthquakes in Denizli basin caused heavy damage to antique cities in the region, namely, Hierapolis in Pamukkale, Laodikeia in Denizli city center, colassae in Honaz, Attuda in Babadag^ and Tripolis in Buldan. A strong earthquake occurred in the early seventh century AD in Lykos (C¸ u¨ru¨ksu) Valley of the Denizli area, heavily damaging the antique cities in the region and causing people to abandon their cities. Recent archaeological excavations in Hierapolis and Laodikeia clearly revealed many relics associated with the early seventh century AD earthquake. For example, the collapse directions of columns and walls are mainly towards the NE or SW. The surface ruptures in the Hierapolis antique city area in the Pamukkale area prove that Pamukkale Fault is the main active fault producing strong earthquakes in the region, and severe damage is induced by earthquakes having a magnitude 6.5 or more. However, the largest earthquake could be up to 7.1 in the Denizli Basin.