Study of Satellite Side Look effect on efficient Source Parameter Identification in Zarand Feb-2005 Earthquake, Based on SAR Interferometry

Authors
M. S. Pakdaman 1
Z. Golshadi 2
M. Rezapour 2
1 Department of Remote Sensing and GIS at Science & Research Branch, Islamic Azad University, Tehran, Iran
2 Department of Physics of the Earth, Institute of Geophysics, University of Tehran, Tehran, Iran
Abstract


The 2005 Zarand earthquake occurred on February 22 at 02:25:26, according to local time in Kerman province in Iran. The main Shock measured 6.5 on moment magnitude scale. Finding causative fault properties and parameters of this earthquake to get reliable values is priority of most researchers. Earthquake source parameters serve as a noteworthy database for synthesizers in seismology and as an essential starting point for the applied theoreticians. Determination of source parameters could make feasible a new level of understanding in many seismological studies that can be used with reported earthquake locations simultaneously to demonstrate boundaries of tectonic plates. It can provide critical information for earthquake hazard assessment and for improved understanding of the earthquake process. Moving towards exact and precise determination of source parameters is essential to reduce uncertainty at other desired stages. The primary purpose of this study is to ameliorate estimation of source parameters and computer simulations of earthquakes, examine the effect of a two sets of rupture parameters on synthesized strong ground motion via forward modelling and checking that which set parameters can be used to predict very realistic source parameters confirmed with Finite fault method. Source parameters of the 2005 Zarand earthquake have already been computed using diverse studies, including seismicity, the earth’s surface deformation field, and rupture characteristics. Each of these studies proposes different mechanisms for this earthquake.

Methodology

Satellite SAR data can gather different information of fault’s physical and geometric situation, because of imagery of two different geometry (ascending and descending), that this lead to optimum extraction of any causative fault parameters. InSAR has become a commonly used technique to measure surface deformation. Measurements by the SAR satellites are made obliquely below the satellite during both ascending orbits (where observations are made from the west) and descending orbits (where observations are made from the east). Two pairs of ascending and descending ENVISAT/ASAR images are available to study the coseismic deformation field of the Zarand 2005 earthquake. We can reconstruct earthquake causative fault parameters using combination of SAR observations and elastic displacement modelling (Okada, 1985). (Feigl, 2002) demonstrated the principles of obtaining earthquake causative fault parameters through elastic displacement modelling using SAR observations.

Though the source parameters are assumed completely unknown, we must set, for each parameters, a range of values between a lower and upper values. In fact, the basic premise for calculating source parameters of an earthquake using SAR observations in inversion processing will be some numbers with appropriate variation ranges.

Strong ground motion data provides researchers with very important information about the simulation of ground motion, rupture processes of earthquakes and consequently source parameters of an earthquake. Finite-fault modeling is widely used for the prediction of ground motion near the epicenters of large earthquakes. In the stochastic model, a large fault is divided into N subfaults, and each subfault is considered as a point source. A random slip distribution is assumed by using a random number as the basis to assign a relative slip to each subfault. Ground motions due to subfaults are calculated by the stochastic point-source method and are summed with an appropriate delay time to produce the motion due to the whole rupture. We have used the extended earthquake fault simulation program EXSIM (Motazedian & Atkinson, 2005) to simulate ground motion.

The study is based on data recorded by the Iranian Strong Motion Network which is run by the Building and Housing Research Center (BHRC). The data are recorded by three-component SSA-2 accelerometers with a threshold of 10 Gals at a sampling rate of 200 samples per second. This earthquake is recorded at the Zarand, Chatrud, Ravar, Horjand, Dasht-e-Khak, Davaran, Kerman1, Kerman2, Hinaman, Baghin, Tarz, Rafsanjan, Bardsir, Sirch, Kuhbanan, Shahr-e-Babak, Bayaz, Anar, Bahadoran, Bahabad, Pariz, Bafgh, Molla Esmaeil, Nayband, Mehriz, Cheshme Sabz, Saadat Abad and Darbehesht stations. In the next step, accelerograms simulation using estimated causative fault parameters in each satellite orbit is done, using stochastic finite fault method. Then results of both ascending and descending orbit are compared to observed values in each station.

Results and discussion

We use the maximum values recorded in each station and obtain results of simulated satellite data to final assessment. The results are demonstrated that the lowest difference in maximum values recorded in each orbit, belong to obtained results of satellite descending orbit data modelling with 5.36% accuracy in comparison to ascending orbit with 7.51% accuracy. Finally, the width, length, strike, dip, rake, depth, slip and coordinates of center causative fault of Zarand earthquake are 6.5 km, 15 km, 279 deg, 90 deg, 55 deg, 5 km, 2.9 m, 483333.4 easting and 3406437 northing, respectively. This procedure allows us to move forward from results with less accuracy to greater one for fault parameters.

Conclusion

The maximum absolute value of accelerograms is used for comparing between synthetic and observed peak ground acceleration in time series. We can say that estimated causative fault parameters for 2005 Zarand earthquake of descending orbit data is more accurate in comparison to ascending orbit data. Finally, we compare our results with Building and Housing Research Centre (BHRC) of Iran, Iranian Seismological Center(IGUT), USGS, IIEES, ISC, CMT catalogue, Talebian et al. (2006), Nicknam et al. (2007), Rouhollahi et al. (2012) reports. Our obtained depth is more similar to Talebian et al. (2006) report. The length of our fault is similar to Nicknam et al. (2007), Rouhollahi et al. (2012) reports. Our width of fault is differ from other studies. Our obtained strike is exactly similar to USGS one’s. Our dip and rake is differ from other studies. Our slip for Zarand causative fault is very similar to Rouhollahi et al. (2012) one’s.

Keywords

Subjects

Ambraseys, N. N., & Melville, C. P. (2005). A History of Persian Earthquakes, Cambridge University Press. doi.org/10.1002/eqe.4290110412
Beresnev, I. A., & Atkinson, G. M. (1997). “Modeling finite-fault radiation from the ωn spectrum”, Bulletin of the Seismological Society of America, 87.
BHRC. Building and House Research Center accelerometer network. Retrieved from www.bhrc.gov.ir
Bolton Seed, H., Murarka, R., Lysmer, J., & Idriss, I. M. (1976). “Relationships of maximum acceleration, maximum velocity, distance from source, and local site conditions for moderately strong earthquakes”, Bulletin of the Seismological Society of America, 66(4), 1323-1342.
CMT. Harvard Un. catalogue, Department of Geological Sciences, Centroid Moment Tensor catalogue. Retrieved from http://www.seismology.harvard.edu/CMTsearch.
Feigl, K. (2002). “Estimating Earthquake Source Parameters from Geodetic Measurements”. In H. K. P. C. J. William H.K. Lee & K. Carl (Eds.), International Geophysics (Vol. Volume 81, Part A, pp. 607-cp601): Academic Press.
Ferretti, A. (2014). Satellite InSAR Data: Reservoir Monitoring from Space, EAGE Publications. DOI: 10.1109/MGRS.2015.2398392
IGTU. Institute of Geophysics, the University of Tehran. Retrieved from http://irsc.ut.ac.ir.
IIEES. International Institute of Earthquake Engineering and Seismology. Retrieved from http://www.iiees.ac.ir.
Irikura, K. (1986). “Prediction of strong acceleration motion using empirical Green's function”, Paper presented at the 7th Japan Earthquake Engineering Symposium, Tokyo.
Irikura, K. (1992). “The construction of large earthquake by a superposition of small events. Paper presented at the Proc”, 10th World Conf. Earthq. Eng.
ISC. International Seismological Center, Engdahl Catalougue. Retrieved from http://www.isc.ac.uk.
Jafari, M. K., & Moosavi, S. M. (2008). “Lessons to be Learned from Surface F ault Ruptures in I ran Earthquakes”. Paper presented at the Sixth International Conference on Case Histories in Geotechnical Engineering.
Mahani, A. B., & Kazemian, J. (2007). “Strong Ground Motion Parameters Of February 22, 2005 Dahuiyeh (Zarand) Earthquake In Central Iran”, international earthquake symposium kocaeli 2007.
Marquardt, D. (1963). “An Algorithm for Least-Squares Estimation of Nonlinear Parameters”, Journal of the Society for Industrial and Applied Mathematics, 11(2), 431-441. doi:10.1137/0111030
Massonnet, D., & Feigl, K. L. (1998). “Radar interferometry and its application to changes in the Earth's surface”, Reviews of Geophysics, 36(4), 441-500. G03139. doi.org/10.1029/97RG03139
Motazedian, D., & Atkinson, G. M. (2005). “Stochastic Finite-Fault Modeling Based on a Dynamic Corner Frequency”, Bulletin of the Seismological Society of America, 95(3), 995-1010. DOI: 10.4236/ojer.2016.52009
Nemati, M. (2015). “Insights into the Aftershocks and Inter-Seismicity for Some Large Persian Earthquakes”, Journal of Sciences, Islamic Republic of Iran, University of Tehran, 26, 35 - 48.
Nemati, M., & Gheitanchi, M. (2011). “Analysis of 2005 Dahuieh (Zarand) aftershocks sequence in Kerman province southeast of Iran”, journal of Earth and Space Physics, Institute of Geophysics, University of Tehran, 37, 1-9.
Nicknam, A., Eslamian, Y., & Bozorgnasab, M. ( 2007). “Modification of seismological parameters of Zarand earthquake (2005 February 22), in central Iran, Using Empirical Green’s function method”, Paper presented at the Australian Conference.
Nissen, E., Jackson, J., Jahani, S., & Tatar, M. (2014). “Zagros “phantom earthquakes” reassessed—The interplay of seismicity and deep salt flow in the Simply Folded Belt?”, Journal of Geophysical Research: Solid Earth, 119(4), 3561-3583. doi:10.1002/2013JB010796
Nissen, E., Yamini-Fard, F., Tatar, M., Gholamzadeh, A., Bergman, E., Elliott, J. R., . . . Parsons, B. (2010). “The vertical separation of mainshock rupture and microseismicity at Qeshm island in the Zagros fold-and-thrust belt, Iran”, Earth and Planetary Science Letters, 296(3–4), 181-194. doi:http://dx.doi.org/10.1016/j.epsl.2010.04.049
Okada, Y. (1985). “Surface deformation due to shear and tensile faults in a half-space”, Bulletin of the Seismological Society of America, 75(4), 1135-1154.
Rouhollahi, R., Ghayamghamian, M. R., Yaminifard, F., Suhadolc, P., & Tatar, M. (2012). “Source process and slip model of 2005 Dahuiyeh-Zarand earthquake (Iran) using inversion of near-field strong motion data”, Geophysical Journal International, 189(1), 669-680. doi:10.1111/j.1365-246X.2012.05387.x
Safarshahi, M., Rezapour, M., & Hamzehloo, H. (2013). “Stochastic Finite Fault Modeling of Ground Motion for the 2010 Rigan Earthquake, Southeastern Iran”, Bulletin of the Seismological Society of America, 103(1), 223-235. DOI:10.1785/0120120027
Sharifikia, Mohammad (2012) “Subsidence Value Estimation Through Differntial Interferometric SAR in Nough-Bahreman Plain”, The Journal of Spatial Planning. [In Persian]
Sharifikia, Mohammad (2017) “River Morphologic Analysis Caused by Taleghan Dam Construction Based on Temporal Diffrential of Remote Sensing Data”, The Journal of Spatial Planning. [In Persian]
Talebian, M., Biggs, J., Bolourchi, M., Copley, A., Ghassemi, A., Ghorashi, M., . . . Saiidi, A. (2006). “The Dahuiyeh (Zarand) earthquake of 2005 February 22 in central Iran: reactivation of an intramountain reverse fault”, Geophysical Journal International, 164(1), 137-148. doi:10.1111/j.1365-246X.2005.02839.x
Talebian, M., Fielding, E. J., Funning, G. J., Ghorashi, M., Jackson, J., Nazari, H., Wright, T. J. (2004). “The 2003 Bam (Iran) earthquake: Rupture of a blind strike-slip fault”, Geophysical Research Letters, 31(11), n/a-n/a. doi:10.1029/2004GL020058
USGS. United State Geological Survey. Retrieved from http://www.neic.usgs.gov.
Vernant, P., Nilforoushan, F., Hatzfeld, D., Abassi, M., Vigny, C., Masson, F., Chéry, J. (2004). “Contemporary crustal deformation and plate kinematics in Middle East constrained by GPS measurements in Iran and northern Oman”, Geophysical Journal International, 157, 381-398. doi.org/10.1111/j.1365-246X.2004.02222.x
Walker, R., Jackson, J., & Baker, C. (2003). “Surface expression of thrust faulting in eastern Iran: source parameters and surface deformation of the 1978 Tabas and 1968 Ferdows earthquake sequences”, Geophysical Journal International. doi:10.1046/j.1365-246X.2003.01886.x
Zafarani, H., Noorzad, A., & Bargi, K. (2007). “Stochastic Finite-Fault Strong Ground-Motion Simulation Of The 22 February 2005 (Mw 6.4) Zarand (Central Iran) Earthquake”, Paper presented at the 4th International Conference on Earthquake Geotechnical Engineering.
Zare, M. (2005). “The Dahuiyeh (Zarand, Iran) Earthquake of 22 February 2005”, Ms6.5, A preliminary Field and Seismological Observation.
The Journal of Spatial Planning and Geomatics
Volume 22, Issue 2
August 2018
Pages 23-46