Paleoearthquakes of the past 30,000 years along the North Tehran Fault (Iran)

摘要: The North Tehran Fault (NTF) is located at the southernmost piedmont of Central Alborz and crosses northern suburbs metropolis adjacent cities, where ∼15 million people live. Extending over a length about 110 km, NTF stands out as major active fault represents an important seismic hazard for Iranian capital after historical seismicity. In order to characterize activity in terms kinematics, magnitude recurrence intervals earthquakes, we carried first paleoseismological study within its central part between Karaj cities. We opened trench across 3 m-high scarp affecting Quaternary deposits. Our shows that result repeated events along main N115°E trending shallow dipping thrust fault, associated with secondary ruptures. From analysis Infrared Stimulated Luminescence (IRSL) dating fault-related sediments, interpreted 6 7 surface-rupturing occurred during past 30 kyrs. Their magnitudes (estimated from displacements faults) are comprised 6.1 7.2. two last - largest 7.9 ± 1.2 ka, which yields Holocene slip rate ∼0.3 mm/yr. earthquakes scenario suggests regular periodicity mean interval ∼3.8 However, most recent could correspond recorded area (in 312-280 B.C. 1177 A.D.), therefore suggest not regular.