Paleoseismological Three Dimensional Virtual Photography Method, Case Study: Duru-2012 Trench, Tuz Golu Fault Zone, Central Anatolia, Turkey

Abstract

Paleoseismology is an active tectonic discipline that tries to obtain information about the location, time and magnitude of paleoearthquakes by using geological and geomorphological data. Paleoseismic trenching is the most important method that is frequently used in paleoseismology and provides considerable data. One of the most important problems encountered especially in deep and benched paleoseismological trench works is the visual representation of the trench stratigraphy and structure to the reader. In this paper, "Paleoseismological Three Dimensional Virtual Photography Method", a new photographic method for paleoseismology, is presented with a case study. Paleoseismological Three Dimensional Virtual Photography Method consists of four stages which are respectively: planning, photographing, stitching and constraction of virtual tour. Paleoseismological Three Dimensional Virtual Photography Method has been applied for the first time during the paleoseismological studies carried out on the Tuz Golu Fault Zone (Central Anatolia, Turkey). The Tuz Golu Fault Zone (TGFZ) is one of the most important intra-continental active fault zones in the Central Anatolian Region. TGFZ is an approximately 200 km-long, NW-SE trending, active normal fault zone with a right lateral strike-slip component. The Akhisar-Kilic segment is one of the most important segments of TGFZ which is composed of fault segments parallel or sub-parallel to each other and with lengths varying between 9 and 33 km. In this study, a paleoseismic trench (Duru-2011) has been excavated on the middle section of Akhisar-Kilic segment. As a result of the evaluation carried out making use of paleoseismological criteria such as trench microstratigraphy, geometry of fault colluvial wedge, upward termination of fault strands, and C-14 age data, three paleoseismic events were described within the Duru-2011, which occurred in the last 23 000 years. On the other hand, in the last 10 500 years two paleoseismic events has been described within the another paleoseismological study. Earthquake data collected from the two trenches on the same segment were evaluated by "fault window method". And averagely earthquake recurrence period of Akhisar-Kilic segment was calculated as 10390 year. Short time (Late Pleistocene - Recent) annual vertical slip rate of Akhisar-Kilic segment was calculated as 0,034 mm/year. This value is well consistent with long term (Late Pliocene) vertical geological slip rate (0,046 mm-year) of segment.