Investigation of Source Parameters of Roudbar-Manjil Earthquake Using Hybrid Simulation Method

Document Type : Original Article


1 MSc Student in Earthquake Engineering, Department of Civil Engineering,University of Tehran

2 Associate Professor, International Institute of Earthquake Engineering and Seismology (IIEES)

3 Associate Professor, Department of civil Engineering, University of Tehran


For time history analysis of structures, appropriate records are needed. Due to the lack of strong-motion records from large earthquakes in some parts of Iran (e.g. Tehran region), earthquake simulation is a useful tool for studying strong-motion characteristics. In this study, a hybrid method has been used for obtaining source parameters of the 1990 Rudbar-Manjil earthquake (Mw7.3). In this simulation we assume fault plane, slip distribution and etc., then each parameter optimized after comparing simulated results with observed ones. In this hybrid method low frequency component of record obtained by the wave-number scheme that is a deterministic method and high frequency component obtained by the stochastic simulation method of Boore (2003), extended to the case of finite faults. Records from the stochastic method filtered with a high pass filter (fc=1.5 Hz) and results from the deterministic method filtered with low pass filter (fc=1.5 Hz), then the time-histories have been combined/added in the time domain. Final results have been compared with observed PSA and PSV in specified strong-motion stations. After comparing, optimized parameters have found, then based on this optimized parameters intensity contour has drawn; simulated intensity contours show good match with and observed ones. Best parameters are 2500 m/s for rupture velocity and 3 seconds for ramp function (i.e. rise time) and 36.82° N and 49.40° for earthquake epicenter. The results are important for the assessment of hazards in other seismically active parts of Alborz mountains (e.g. Greater Tehran area).


R. N. Iyengar and S. Raghukanth, "Strong Ground Motion Estimation During the Kutch, India Earthquake," Pure and Applied Geophysics, vol. 163, no. 1, pp. 153-173, 2006.
H. E. Zaineh, H. Yamanaka, Y. P. Dhakal, R. Dakkak and M. Daoud, "Strong ground motion simulation during the November 1759 Earthquake along Serghaya Fault in the metropolitan of Damascus, Syria," Journal of Seismology, vol. 17, no. 4, pp. 1295-1319, 2013.
M. Berberian, M. Qorashi, J. A. Jackson and K. Priestley, "The rudbar-tarom earthquake of 20 june 1990 in nw persia: preliminary field and seismological observations, and its tectonic significance," Bulletin of the Seismological Society of America, vol. 82, no. 4, pp. 1726-1755, 1992.
M. Berberian and R. Walker, "The RudbarMw7.3 earthquake of 1990 June 20; seismotectonics, coseismic and geomorphic displacements, and historic earthquakes of the western ‘High-Alborz’, Iran," Geophysical Journal International, vol. 182, p. 1577–1602, 2010.
J. Campos, R. Madariaga, J. Nábělek, B. G. Bukchin and A. Deschamps, "Faulting process of the 1990 June 20 Iran earthquake from broad-band records," Geophysical Journal International, vol. 118, no. 1, pp. 31-46, 1994.
M. Tatar and D. Hatzfeld, "Microseismic evidence of slip partitioning for the Rudbar-Tarom earthquake (Ms 7.7) of 1990 June 20 in NW Iran," vol. 176, no. 2, 2009.  
]7[  م. رحیمی, حل معکوس بر روی گسل‌های محدود با استفاده از الگوریتم ژنتیک, پایان نامه کارشناسی ارشد مهندسی سازه، نورزاد، ا )استاد راهنما( ، زعفرانی، ح )استاد راهنمای دوم(، انصاری، ا )مشاور(, ۱۳۹۲.
D. J. Wald, V. Quintoriano, T. H. Heaton and H. Kanamori, "Relationship between Peak Ground Acceleration, Peak Ground Velocity, and Modified Mercally Intensity in California," Earthquake Spectra, vol. 15, no. 3, pp. 557-564, 1999.
S. T. G. Raghukanth, "Ground motion estimation during the Kashmir," Natural Hazards, vol. 46, no. 1, pp. 1-13, 2007.