Morphotectonics and Paleoseismology investigation on Sahlan Fault Fragment, NW segment of the North Tabriz Fault

The North Tabriz Fault is one of the major strike-slip faults (trending NW-SE) in NW Iran، that trends from Sofian to Bostan Abad. Generally، the fault consists of two main fault segments. In present research، to study the last active tectonics at the North Tabriz Fault region، evaluated young morphotectonical features and paleoseismology of northwestern fault segment evaluated. On the basis of morphotectonic approaches on this region، horizontal slip last event (MW = 7. 4، 1780 AD) are found in the ranges 3. 5 ±0. 5 m and vertical slip between 0 and 0. 5 m. However، by attention to H/V ratio can propose that NW segment of North Tabriz Fault act as pure strike slip which confirm by new GPS data on this part of Iran. On the basis of paleoseismological researchs، by examining a wall perpendicular to the North Tabriz Fault in North Sahlan Village، four old paleoearthquakes with relative magnitude of MW = 6. 4 has been detected. A young magnitude of the event، recorded in deposits of the paleoseismologic trench of the study area، close to 7 have been estimated that according to geographic and stratigraphic location، this event can be associated with historical earthquakes since 1780 AD (MW = 7. 4).