Dendroseismology on the central North Anatolian fault, Turkey: Documenting three centuries of surface rupture history using tree rings

Abstract

Tree ring analysis provides a precise dating source for characterizing the timing of natural hazards. Specifically, seismogenic disturbances on trees have been successfully documented on major faults such as the San Andreas fault in California and Denali fault in Alaska. In this study, dendroseismology was employed along a 15-km-long stretch of the central North Anatolian fault (NAF) between Ilgaz and Tosya, Turkey where the most recent surface rupturing event was the Mw 7.6 1943 A.D. earthquake. Morphologic documentation and dendrochronologic analyses of 28 Pinus sylvestris trees demonstrates the effects of proximal surface rupture and secondary earthquake deformation. Fourteen trees show similar abrupt growth suppression and accelerated recovery trends following the 1943 A.D. Tosya earthquake. The number of trees yielding similar results, the linear spatial distribution of the traumatized trees along the NAF, similarity in the trend of annual ring growth response, and synchronity of these anomalies with the 1943 A.D. earthquake provide robust evidence for the correlation of the observed anomalies and the earthquake. In addition, four trees going back to early 18th century provide evidence for the lack of another surface rupturing large magnitude earthquake along this stretch of the fault. This finding corroborates that the historical 1668 A.D. earthquake is most likely the penultimate event for the Ilgaz-Tosya segment of the NAF. Copyright 2012 by the American Geophysical Union.