Determination of causative fault parameters for some recent Iranian ...

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H. Hamzehloo / Journal of Asian Earth Sciences 25 (2005) 621–628
Fig. 4. The fault plane solutions of the 1997 Ardebil earthquake given by HRV (gray) and this study (black).
Tehran) in NW Iran at 2:58:27.2 (GMT) (7: 28: 00 local
time). The earthquake killed over 226 people and injured
more than 1300. The earthquake was felt at Tehran and
affected 373 villages in Ghazvin, Hamedan, Zanjan, and
Markazi provinces. Maximum accelerations of 4.29
and 4.55 m/s 2 for the two horizontal components were
recorded at Avaj station (Table 2). The SH-wave accelerogram
records at Abegarm, Abhar, Avaj, Darsajin and
Razan are shown in Fig. 2.
3.5. The 2003 Jahrom earthquake
An earthquake with an estimated magnitude of M W 5.6
occurred on July 10, 2003 at 17:6:37 (GMT) in the Zagros
Mountains southeast of Jahrom in Fars province (Fig. 3).
The earthquake killed one person and injured 25. Maximum
peak ground accelerations of 3.58 and 2.91 m/s 2 for
two horizontal components were recorded at Hajiabad.
The SH-wave acelerogram records at Hajiabad and Jouyom
are shown in Fig. 2.
4. Results
The estimated causative fault parameters using SH-wave
data of recorded accelerographs for the 1994 Zanjiran earthquke,
the 1997 Ardebil earthquake, the 1999 Kareh Bas
earthquake, the 2002 Avaj earthquake and the 2003 Jahrom
earthquake are given in Table 3. The estimated strike, dip
and rake for the the 1994 Zanjiran earthquake using analyses
of SH-wave are 3358, 888 and K1368, respectively.
These values for the 1999 Kareh-Bas are estimated as
strikeZ1458, dipZ878 and rakeZK1608, respectively. For
the 1997 Ardebil earthquake the values of strike, dip and
rake are estimated as 1878, 858 and K108, respectively.
The fault parameters for the 2002 Avaj earthquake are
estimated as strikeZ1188, dipZ538, and rakeZ828, respectively.
These values for the causative fault of the 2003 Jahrom
earthquake are strikeZ3008, dipZ428 and rakeZ1188.
5. Discussion
5.1. The 1994 Zanjiran and the 1999 Kareh-Bas
earthquakes
The Harvard Centroid Moment Tensor (CMT) solution
gives values of strike, dip and rake for the 1994 Zanjiran
earthquake as 3438, 858, and K1578, respectively, while
the NEIC suggest values 3558, 608 and K1798 for strike,
dip and rake, respectively. It is observed that the values of
strikeZ3358, and dipZ888 from this study are in fair
Table 3
Estimated fault plane parameters using SH-wave analyses
Earthquake NP1
NP2
yy/mm/dd
Str Dip Rake Str Dip Rake
1994/6/20 335 88 K136 243 46 K3
1997/2/28 187 85 K10 278 80 K175
1999/5/06 145 87 K160 54 70 K3
2002/6/22 303 37 94 118 53 82
2003/7/19 300 42 118 84 54 67