Primary report of Kahnouj earthquake 2011 Jun 15 (Kahnouj, Kerman)

Description

Primary report of Kahnouj earthquake 2011 Jun 15 (Kahnouj, Kerman)   Shokri M., Eskandari and M. Zia   Seismotectonic and Seimology Dept. Geological Survey of Iran (GSI)   The Kahnouj earthquake of 2011 Jun 15 (Mn 5.3; IRSC- Mw 5.3; USGS) occurred at 01:05:28 UTC (05:35:30 local time on 25 Khordad 1390) in Kahnouj City and vicinity villages. The instrumental epicenter of this event given by IRSC is 27.78˚N;57.77˚E; located at the 23 km SE of Kahnouj city and 102 km south of Jiroft city with 34 km in depth (table 1). 18 aftershocks with magnitude 2.5-4.6 were registered by IRSC after about 2 days after the mainshock. On the other hand, a foreshock with magnitude of 4.1 in Mn scale occurred at the 12 km SW of Kahnouj city about 2 minutes before the mainshock. Considering epicenter of the earthquake, it seems that Jiroft-Sabzevaran fault system (N-S) caused this seismic event. Jiroft-Sabzevaran fault system which is located in southern direction of Nayband-Golbaf strike slip fault system joins Makran zone to northern parts of the central Iran and with Nayband-Golbaf fault system include shear strain between central Iran and Lut-Makran area (Regard et al.2005).  Jiroft fault, as an active fault, appears in adjacent south part (~10 Km) of Jiroft town with a north-south (N-S) trend continues to 40 Km of southeast of Kahnouj town. The southern parts of the fault, forms the boundary between Mesozoic metamorphism, ophiolitic mélanges and Jazmourian depression, which is parallel to Sabzevaran fault in southern Kahnouj. The fault in the shape of discrete sections (batches) with 10 to 40 Km length makes western boundary of Jazmourian depression and in northern parts, near Dasht-e-Kouch village, apparently cuts the Quaternary deposits. Sabzevaran fault (about 150 Km) initiates from west of Jiroft town to southwest of Kahnouj town. In northern parts, the fault sharply cuts Pliocene-Quaternary deposits. In southeast of Kahnouj, the fault as a fault-line scrap, separates forehead of Giri mount in the west from Bande Bargah valley in the east, which caused displacement of alluvial terraces and channels or waterways (Shafie bafti et al, 2009).      Table 1   IRSC: IRanian Seismological Center     IIEES: International Institute of Earthquake Engineering and Seismology USGS: U.S. Geological Survey EMSC: European-Mediterranean Seismological Center   Depth (km) Latitude Longitude Magnitude Ref. 34 27.78 57.77 Mn 5.3 IRSC 18 27.94 57.75 ML 5.7 IIEES 36 27.98 57.57 Mw 5.3 USGS 28 27.97 57.66 Mb 5.3 EMSC         Instrumental epicenters of 2011 Jun 15 Kahnouj earthquake(Mn 5.3) Isoseismal map of 2011 Jun 15 kahnouj earthquake