Source Characteristics of the 2012 Ahar-Varzaghan Earthquake

The August 11, 2012 Mw 6.4 earthquakes in northwestern Iran occurred as a result of oblique strike-slip faulting in the shallow crust of the Eurasia plate, approximately 300 kilometer east of the plate boundary between the Eurasia and Arabia plates. The seismotectonics of this region is controlled by the collision of the Arabia and Eurasia plates;at the latitude of the earthquakes, the Arabia plate moves almost due north with respect to the Eurasia plate at a rate of approximately 26 millimeter per year. Over the past forty years, seven earthquakes of Mw 6 or greater have occurred within 300 kilometer of today’s events. The nearest was a Mw 6.1 earthquake in February of 1997, approximately 100 kilometer to the east, which caused 1100 fatalities. The studied area encourage the authors to determine the focal mechanism, source time function and sub events’ features which can guide us to reliable judges.

Measuring the Qatar-Kazeron Fault Dip Using Random Finite Fault Simulation of September 27, 2010 Kazeron Earthquake and Analytical Signal Map of Satellite Magnetic Data

In this research the fault parameters causing the September 27, 2010 Kazeron Earthquake with a magnitude of MW = 5.8 (BHRC) were determined using the random finite fault method. The parameters were recorded by 27 accelerometer stations. Simulation of strong ground motion is very useful for areas about which little information and data are available. Considering the distribution of earthquake records and the existing relationships, for the fault plane causing the September 27, 2010 Kazeron Earthquake the length of the fault along the strike direction and the width of the fault along the dip direction were determined to be 10 km and 7 km, respectively. Moreover, 10 elements were assumed along the length and 7 were assumed along the width of the plane. Research results indicated that the epicenter of the earthquake had a geographic coordination of 29.88N - 51.77E, which complied with the results reported by the Institute of Geophysics Tehran University (IGTU). In addition, the strike and dip measured for the fault causing the Kazeron Earthquake were 27 and 50 degrees, respectively. Therefore, the causing fault was almost parallel to and coincident with the fault. There are magnetic discontinuities on the analytical signal map with a north-south strike followed by a northwest-southeast strike. The discontinuities are consistent with the trend of Kazeron fault but are several kilometers away from it. Therefore, they show the fault depth at a distance of 12 km from the fault surface.

Biostratigraphy of Albian Sediments(Kazhdumi Formation)in Zagros Area(Southwest of Iran)

To investigate biostratigraphy of Albian sediments(Kazhdumi Formation)in the Zagros Basin,280 samples in four sections were prepared which are nominated as Murshan-e-Bala,Fahliyane-Pain,Kupon and Tale-e-Afghani.Stratigraphic distribution of identified foraminifers confirms well developed orbitolinids which are associated with other Albian benthic foraminifers in all studied sections.The orbitolinids are recognized in surrounding strata[Dariyan(at the base which is marked by an oxidized zone)and Sarvak Formations(on the top,as gradtional contact)]as well as the Kazhdumi Formation.Obtained biostratigraphic data show that Early Albian is marked by the presence of Hemicyclammina sigali,which co-occurs with Mesorbitolina texana and Mesorbitolina subconcava,whereas Conicorbitolina conica and Meorbitolina parva support Late Albian age of the studied sections.Calcareous algae are associated with both benthic faunal assemblages.Albian planktons occur in the studied sections which are identified as Favusella washitensis and Calcisphaerula inomminata subzones.The stratigraphic position of planktons actually indicates vertical displacement in the sedimentary basin during Albian time.Other associated Albian pelagic foraminifera are identified which are obviously recognized in three sections of the Kazhdumi Formation.The presence of pelagic species in the study section of the Kazhdumi Formation indicates basement faulting during the Albian period.