SLIP DISTRIBUTION ALONG THE NORTH ANATOLIAN FAULT ASSOCIATED WITH THELARGE EARTHQUAKES OF THE PERIOD 1939 TO 1967

Between 1939 and 1967, six large fault ruptures formed a westward-migr ating sequence of events along a 900-km-long nearly continuous portion of the North Anatolian fault. For these events-the 1939 Erzincan, 194 2 Niksar-Erbaa, 1943 Tosya, 1944 Bolu-Gerede, 1957 Abant, and 1967 Mud urnu Valley earthquakes-I have compiled a record of dextral slip, whic h contains nearly 100 points. These data indicate that the amount of s lip is irregularly distributed along the 1939 to 1967 rupture zone. Th e maximum slip, 7.5 m, occurred during the 1939 earthquake in the east ern 150 km of the 900-km-long rupture zone. Dextral offsets diminish v ery abruptly eastward but very gradually westward. The rate of westwar d decrease in the 1939 to 1967 offsets is only slightly greater than t he rate of westward decrease of post-Miocene displacement along the No rth Anatolian fault. This suggests that westward decrease in slip can be expected to be a general characteristic of earthquake ruptures alon g the North Anatolian fault in the future. Nevertheless, within the 19 39 to 1967 slip distribution, there are three regions that had less sl ip than the neighboring regions. These I interpret as possible sites o f large future earthquakes. One of these seismic gaps has already expe rienced another earthquake (in 1951) and subsequent creep.