AN INVESTIGATION OF GEOLOGIC HAZARDS OF THE NORTH ANATOLIAN SHEAR ZONE NEAR AMASYA, TURKEY

The 2009 National Science Foundation-International Research Experience for Students (NSF-IRES) program in Turkey provided an opportunity for US and Turkish students and professors to collaborate and investigate extensional dynamics in western Turkey, while strengthening cultural and scientific ties. Part of this research focused on the geologic hazards of the North Anatolian Shear Zone (NASZ or North Anatolian Fault) in the Tokat Massif of NE Turkey. The NASZ has been recognized as a significant and seismically active structure, accommodating the lateral escape of the Anatolian block due to collision of the Arabian and Eurasian plates. Key unknowns regarding the NASZ in the Tokat Massif exist, including its (1) slip history, recurrence interval, depth, and sense of motion of structures, (2) petrological and geochronological data, (3) relationship of younger faults with other older structures, and (4) role in triggering rock falls/slides, which characterize the region. This lack of information is significant, as it precludes the development of a realistic hazard assessment map and inhibits understanding of the driving forces that facilitate mass movement along crustal-scale strike-slip faults in general. As part of the NSF-IRES program, our team visited the historically significant town of Amasya, which is greatly affected by these gaps in knowledge. Some key questions were developed, including: What is the relationship between earthquake movement and rock slope failures in Amasya? What is the possibility of occurrence of rock slide/falls due to seismic activity? How do older structures within the NASZ interact and accommodate lateral extrusion of the Anatolian block? Is the Tokat Massif’s petrological and exhumation history important in terms of understanding the slip history of the NASZ or the geomorphologic evolution in the region? In this investigation, we visited mountain-side neighborhoods in Amasya to observe rock slide/fall damage and the relocation of families at risk of mass wasting. We had the opportunity to discuss geological hazards with families who remain in high-risk rock fall zones.