31 Seismicity, palaeoseismicity & archaeoseismology of the Mediterranean region. Part 1

Thursday, 7 October 2010
9:30 AM - 12:30 PM
Salon A

A LATE HOLOCENE SLIP RATE FROM NORTH ANATOLIAN FAULT on HERSEK PENINSULA IN IZMIT BAY, TURKEY

Paper number: 31-7
Program: Scientific Sessions
Time: 11:30 AM – 11:50 AM

Authors

Abstract

Hersek Peninsula has been a strategic location at least for the last two millennia as a result of its location. It extends into the Izmit Bay and creates a shortcut for the Bagdad Road, an important section of the spice route, between Istanbul (Constantinople) and Iznik (Nicaea). It also controls the entrance of the Izmit Bay to Izmit (Nicomedia). Therefore, civilizations have been investing in this location for at least two millennia by building harbors, fortifications, baths, roads, bridges, aqueducts, and temples. The remnants of these historical structures recorded evidence for past destruction of both anthropogenic and tectonic origin. Consequently, from active tectonics point of view, Hersek Peninsula quickly became a key locality for understanding seismic risk in Marmara Region following the M7.4 Izmit earthquake in 1999 since it is the last place that the North Anatolian fault can be studied onland before it enters the Marmara Sea.

We combined both potentials and performed paleoseismic trenching as well as archeoseismologic investigations on Hersek Peninsula in order to investigate seismic hazard in this region. Our paleoseismic trenches north of the Hersek Lagoon provided fault exposures confirming the location of the North Anatolian fault on the peninsula. Furthermore, detailed mapping of a displaced 6th century A.D. Byzantine aqueduct along the projection of this fault exposure revealed a late Holocene slip rate. Although the rapid deposition on the delta plain blankets the evidence of faulting, our trenching in this area provided key insights on the timing of the most recent earthquake that created surface rupture through Hersek Peninsula. This late Holocene slip rate estimate and information about the most recent earthquake at Hersek Peninsula provides invaluable information for the seismic risk calculations and hazard analyses of the Marmara region.