Structural Characteristics, Paleoseismology and Slip Rate of the Qoshadagh Fault, Northwest of Iran

• Published in: Geotectonics Vol. 53; no. 2; pp. 280 - 297
• Main Authors: Faridi, M., Nazari, H., Burg, J.-P., Haghipour, N., Talebian, M., Ghorashi, M., Shokri, M. A., Ahmadzadeh, E., Sahebari, S. S.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01-03-2019; Springer Nature B.V
• Subjects: Arrays; Bends; Earth and Environmental Science; Earth Sciences; Earthquakes; Fault lines; Geomorphology; Paleogeology; Rupturing; Seismic activity; Seismic engineering; Seismic hazard; Seismic properties; Seismic response; Seismology; Slip; Structural Geology; seismotectonics; Azerbaijan province; paleoseismology; morphotectonics; Qoshadagh Fault
• ISSN: 0016-8521; 1556-1976
• DOI: 10.1134/S0016852119020031

Geometric and seismic parameters of the Qoshadagh Fault (QDF) were investigated to evaluate seismic hazard along this fault, which consists of three segments. The central E–W striking, dextral-reverse segment is the longest and terminates at both ends into NW–SE striking splay arrays. Both eastern and western splay arrays form locally transtensional bends. Paleoseismic data obtained from three excavated trenches across the fault combined with dated offset geomorphic features revealed that the central segment experienced at least 5 surface rupturing earthquakes during the past 2.5 ka, with maximum moment magnitude of M
w
= 6.8 ± 0.2. The mean recurrence interval for the identified paleoearthquakes is 452 ± 143 years (±2σ) and the calculated amount of slip per event is ca. ≈0.85 m. These results imply that the QDF slips at an average rate of 1.9 ± 0.1 mm yr
–1
for over the past 2.5 ka. The obtained values define the seismic behavior of the fault and are essential to remediate ensuing seismic risks.