Paleo-earthquake evidence and earthquake recurrence for Düzce fault, Turkey

Abstract

Paleoseismological trenching was performed along the Duzce fault providing some preliminary insight about its seismogenic behavior. Dating was based on radiocarbon analysis of peat samples collected from the trenches and suggested seven earthquakes have occurred since 1740 BC. Integrating date constraints of events exposed in the trenches suggests a periodical earthquake recurrence model. According to a linear sequential event serial that has minimum misfit determined by considering the probability curve limits of the sample dates, the earthquake recurrence interval is between 384 and 460 years (or possibly between AD 394 and 400). A probability curve was also calculated for the date of the last earthquake (1999 Duzce earthquake) considering the probability distributions of sample dates based on the same event serial. This probability-distribution-based method, similarly, predicted that the 1999 Duzce earthquake occurred between 1933 and 2005 (+/- 36 years) with a 68% probability. After this verification, using this method, it was estimated that the next earthquake along the Duzce fault has a 68% probability of occurring between 2328 and 2392. According to this calculation, the earthquake recurrence interval is about 391 +/- 34 years with a 68% probability and the AD 967 historical earthquake likely ruptured the Duzce fault. Assuming an average slip of 350 cm (the average slip of the 1999 earthquake), the slip rate was estimated to be between 8.7 and 11.2 mm/a.