Paleoearthquakes of the past 30,000 years along the North Tehran Fault (Iran) - CNRS - Centre national de la recherche scientifique Accéder directement au contenu
Article Dans Une Revue Journal of Geophysical Research Année : 2012

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

Résumé

The North Tehran Fault (NTF) is located at the southernmost piedmont of Central Alborz and crosses the northern suburbs of the Tehran metropolis and adjacent cities, where ∼15 million people live. Extending over a length of about 110 km, the NTF stands out as a major active fault and represents an important seismic hazard for the Iranian capital after historical seismicity. In order to characterize the activity of the NTF in terms of kinematics, magnitude and recurrence intervals of earthquakes, we carried out a first paleoseismological study of the fault within its central part between Tehran and Karaj cities. We opened a trench across a 3 m-high fault scarp affecting Quaternary deposits. Our study shows that the scarp is the result of repeated events along a main N115°E trending shallow dipping thrust fault, associated with secondary ruptures. From the trench analysis and Infrared Stimulated Luminescence (IRSL) dating of fault-related sediments, we interpreted between 6 and 7 surface-rupturing events that occurred during the past 30 kyrs. Their magnitudes (estimated from the displacements along the faults) are comprised between 6.1 and 7.2. The two last events - the largest - occurred during the past 7.9 ± 1.2 ka, which yields a Holocene slip rate of ∼0.3 mm/yr. The 7 earthquakes scenario suggests a regular periodicity with a mean recurrence interval of ∼3.8 kyrs. However, the two most recent events could correspond to the two largest historical earthquakes recorded in the area (in 312-280 B.C. and 1177 A.D.), and therefore suggest that the NTF activity is not regular.
Fichier principal
Vignette du fichier
ritz2012.pdf (10.19 Mo) Télécharger le fichier
Origine : Fichiers éditeurs autorisés sur une archive ouverte
Loading...

Dates et versions

hal-00757568 , version 1 (27-11-2012)
hal-00757568 , version 2 (30-01-2017)

Identifiants

Citer

J.F. Ritz, Amid Nazari, S. Balescu, M. Lamothe, Reza Salamati, et al.. Paleoearthquakes of the past 30,000 years along the North Tehran Fault (Iran). Journal of Geophysical Research, 2012, 117, pp.B06305. ⟨10.1029/2012JB009147⟩. ⟨hal-00757568v2⟩
218 Consultations
207 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More