Qir-Karzin Earthquake of 10 April 1972, Mw=6.9
On 10 April 1972, a Mw6.9 earthquake occurred in Qir-Karzin region of the Fars Province, Iran. The earthquake, which was preceded by a number of alarming foreshocks, killed 5010 and injured 1710 people in 50 villages; this was about 20% of the population of the Karzin Borough of the Fars province in the central Zagros. Haghipour et al. (1972) introduced two WNW–ESE trending, very long surface faults by dotted lines and considered them as a “fault, probably reactivated.” Their northern line in the Qir plain has a N120°E trend with a 32-km length; whereas the southern one in the Dasht-e Shur/Afzar plain has a strike of N110°E and a length of 71 km. They introduced the small central sections of these two speculated faults as lines of “extreme lurching, tension cracks, and few pressure ridges.” No evidence of such coseismic surface faulting was observed. Sobouti et al. (1972) introduced a 15-km-long “fracture and trace of fault” in an ~N136°E direction, which could not be traced in the field. Ambraseys (1975) reported a 20-km-long fault break with an azimuth of N120 Ambraseys and Jackson (1998) changed the statement to a 20-km long spurious surface faulting striking N120°E with 5 cm horizontal and 25 cm vertical displacements. The discontinuous surface fractures mapped by Ambraseys et al. (1972) and Ambraseys and Melville (1982) can be categorized in two groups: (i) the easternmost NNW-striking, en-echelon fractures with right-lateral displacement and (ii) the rest of the fractures with mostly NW-trending ground ruptures (with two cases of almost N–S fractures) in the southeast Qir and to the west of the meizoseismal area (Figure 13.4). The first group of the fractures is located in the Sabzpushan right-lateral strike-slip shear zone and may indicate that the shear zone was reactivated. The second group of fractures developed on the folds above the Surmeh reverse fault, indicating flexural-slip faulting on the Surmeh anticline. Almost all the surface deformations took place above the Surmeh reverse fault, the only reverse fault in the central Zagros along which the Paleozoic sediments have surfaced (Berberian, 1995). The Karzin earthquake possibly took place along the Surmeh reverse fault at depth, which did not propagate to the surface (Berberian, 1995). Known earthquakes in the area were recorded in 1440 (M 14 November 1903 (VII at Qir), 14 September 1968 (M 1973 (Ms4.8), and 2 February 1985 (Mwws6.9),5.8), 24 February 5.6) (Berberian, 1995). The pre-1900 earthquakes left no historical monuments in the Karzin borough of the cultural rich Fars province to be damaged by the 1972 Karzin earthquake
Source of old photos: http://parguon.ir
Source of text: Berberian, M., 2014, Earthquakes and Coseismic Surface Faulting on the Iranian Plateau, 1st Edition, Elsevier, Print Book ISBN: 9780444632920, eBook ISBN: 9780444632975, 776 pages.