Iran quake on April 16th was largest in almost 40 years.
An earthquake with a preliminary magnitude of 7.8 (M7.8) has occurred in eastern Iran, close to the border with Pakistan. The tremor struck at a quarter to 11 UTC on Tuesday 16 April, at a depth of around 15km, according to the United States Geological Survey.
First reports at the time of writing suggest that several people have been killed, and early indications suggest that the tremor was felt as far away as Delhi, Dubai and Bahrain.
The earthquake comes just a week after an M6.3 tremor, followed by a cluster of aftershocks, struck further east in the country, close to the nuclear power plant at Bushehr. Last week’s quake caused at least 37 fatalities.
The two earthquakes are, however, unlikely to be related as they occurred in different tectonic settings, although both are governed by the overall convergence of tectonic plates along the southern margin of Eurasia.
Causes of the Earthquake: Tectonic Setting of Iran
Iran lies on the southern edge of the Earth’s Eurasian tectonic plate, predominantly composed of thick, relatively buoyant, continental crust. Along the southern margin of this plate, the northward movement of the African, Arabian and Indo-Australian plates creates major earthquake-prone seismic zones.
The 16 April earthquake occurred in eastern Iran, where the complex direction of compressional movement of the Arabian plate against the Eurasian plate and its relationship to the Himalayas (uplifted by northern movement on India) has given rise to a complex series of north-south trending faults.
Although local information is currently unavailable, it seems likely that lateral movement along one of these strike-slip faults caused this Magnitude 7.8 quake.