Goharan, Bashagard Earthquake of 11 May 2013, Mw=6.2
The earthquake occurred at 6:38 local time in a sparsely populated region, close to the Minab-Zendan fault Zone, which marks the western end of the Makran ranges. The recent seismicity in the Makran zone shows that the earthquakes of 16 April and 11 May 2013 are the major events in this region during the last nine years. There was a foreshock of Magnitude mb 5.0 on 9 May 2013, at 12:31 a.m. (local time), which produced a preliminary alert mid-day and resulted in the evacuation of the residents, in order to be temporarily relocated to the local tents named as “Kapar”. Therefore during the main shock there was only one victim (a 2 year old girl) in Irar. The epicenter was located close to Irar, 10km north of Goharan, about 25km north of Sardasht. The focal mechanisms are reported to be mostly strike-slip. According to the existing faults in the region, the Manujan fault with a right lateral strike-slip movement and a NW-SE trend having a slip towards the east is expected to be the causative fault. The location of the epicenter and the fault slip towards the east might be a justification for a depth between 20 to 25km for this earthquake. This fault is parallel to the Minab-Zendan-Palami fault zone. The surface fissures, observed around the road from Goharan to Irar (kilometer 5, north of Goharan, and just at the end of this road. However it does not present the systematic evidences of surface fault rupturing, it continues in an en-echelon NE-SW direction near Irar, for about 5kms, and the fissure segments mostly have azimuths of N320 to N330. The shakemaps were developed immediately after the mainshock, showing the maximum assessed intensity to be VI+ around the epicenter. A visit to the epicentral region showed that the macroseismic epicenter was located in Irar village, that experienced an intensity of VI+ (EMS98) and the intensities are assessed to be VI in Goharan, Sardasht and Bolbolabad, and V in Jakdan, Patahk and Senderk, V in Minab and Jask and III in Bandarabbas. The strong motions of this earthquake was recorded by the accelerometric stations of the Building and Housing Research Center (BHRC; http://www.bhrc.ac.ir/portal/Default.aspx?tabid=1276). There are 2 records obtained in Senderk and Sirik. The most important records was obtained in Senderk having the highest PGA of 16.7 cm/sec2, after correction, at a hypocentral distance of 49km. There were some ground fissures in the road from Irar to Goharan, as well as a major rock slide about 5km north of Goharan. There is an old rock slide (possibly related to a previous earthquake in the same location, with the same size of dislocated rock blocks, but no document is found yet on such probable historical earthquake. The population of Goharan in about 6,000 and the all of the villages around Goharan have about 9,000 inhabitants. Most of the observed damage was in Irar village, where some buildings were extensively fissured and out-of-use. The casualties were evidently intensified in the aftershock that occurred in 18 May (M5.7). The urgent sheltering performed first by the people themselves using their hand-made tents (Kapar’s) and then byIranian Red Crescent Society; IRCS. There were some walls collapsed in Irar and some shear cracks. The damages were slight in Goharan, for instance in Goharan Municipality no major casualty was observed, however the temporary shelters were installed by IRCS. 3,612 tents were installed in the region.
