THE IMPACT OF TECTONIC AND MASS-WASTING PROCESSES ON ANCIENT CIVILIZATIONS - THE CASE OF SARDIS, WESTERN TURKEY

The ancient city of Sardis, located along the flank of the Gediz Graben in western Turkey, was once the capital to the ancient kingdom of Lydia and remained important during Roman and Byzantine times. The area experienced major earthquakes in 17 CE and ca. 650-700 CE causing severe damage to the site. The archaeological site stands up to 300 m above the Gediz plain and is built upon a highly dissected hill comprised of Neogene Acropolis Conglomerate. These weakly cemented sediments supply debris to the hillslopes, frequently resulting in mass wasting during earthquakes and torrential rainfall periods during springtime. Mass wasting processes range from slumping to debris and mud flows. In addition to the weak lithology and Mediterranean climate, anthropogenic impacts since Lydian times have alleviated the effects of mass wasting. The Temple of Artemis, for example was buried by several meters of landslide debris, most likely between the late seventh and eighth century CE. Since no major earthquake activities were reported for the period, heavy rainfall may have triggered a catastrophic landslide which was identified during early excavations. During a field reconnaissance study of the area in the Spring of 2012, we surveyed and mapped the area of the temple and its adjacent uplands using a Terrestrial Laser Scanner. This was done to identify the main source areas of landslide debris and to reconstruct topographic conditions before landslide failure in an attempt to estimate the volume of material movement. A clear dependency between mass wasting and heavy rainfalls was observed during the spring 2012 field season. A fresh landslide scar was observed about 700 m east of the temple. Further field surveys in the valley southeast of the temple discovered gully erosion and small debris flows on farmland in the vicinity of the archeological remains. This corroborates earlier findings linking agricultural usage and increased erosion rates. A more refined topographic map helps to identify hazardous areas, such as landslide source areas channels that may control future mass wasting. The new data also form a basis for estimating long-term sediment transfer. Lastly, we pinpointed some areas where agricultural use could be scaled back to benefit the protection of the archaeological site.