A strong and very shallow earthquake struck southern Iran on April 9, 2013 at 11:52 UTC. Epicenter was located 89 km (55 miles) SE of Bandar Bushehr, Iran and 92 km (57 miles) SSE of Borazjan, Iran at coordinates 28.500°N, 51.591°E. Both USGS and EMSC measured depth of only 10 km (6.2 miles) and reported same preliminary magnitude.
The quake has been given "orange alert level" by USGS, meaning significant casualties are likely and the disaster is potentially widespread.
The earthquake's epicenter was 89 kilometers (55 miles) away from the Bushehr nuclear facility, just outside the town of Kaki. By reports the plant is functioning normally.
A strong M 5.4 aftershock was reported by both agencies at 12:05 UTC today at the same coordinates, the difference in reports were in depth. EMSC reported aftershock at depth of 80 km whereas USGS reported depth of 10 km again.
IIEES, Iran, reports magnitude M 6.1 earthquake. It has been felt in Bahrain, Qatar, UAE and Saudi Arabia.
GDACS said this earthquake can have a low humanitarian impact based on the magnitude and the affected population and their vulnerability. There are 700 000 people living within 100 km radius.
ER reports that the earthquake was felt across the region. Magnitude 6.2 in southern Iran can often cause major damage especially when at a shallow depth. It is worth remembering that the 2003 Bam earthquake had a magnitude around 6.5, and caused around 25,000 deaths. Magnitude 6.0 earthquake struck the same region of Khornooj in 1976 on the 22nd of April causing some damage but no fatalities.
The earthquake has occurred near the Borozjan fault, near a salt dome.
This was destructive and deadly earthquake. There are 37 confirmed deaths so far and more than 800 injured. Many landslides have been seen. 23 villages are affected by the quake, the government says.
20 rescue personnel in 4 assessment teams, and 2 helicopters have been sent. Red crescent assessment teams were also sent. Kaki city has some destroyed houses, and some poorly built rural houses in Bushehr (around 50-60km away) have cracking.
Villages in Kaki and closer have some homes that have collapsed. Some buildings in the Dubai Marina area have been evacuated and workers sent home according to Gulf News sources.
Strong aftershocks continue.
Summary at 18:00 UTC by ER:
The number of severely injured: 100
The number of slightly injured: 750
Pulled from the rubble (rescued): 20
Rescuers on site: 500
Aftershocks so far (significant): 42
There have been 3 villages that have been completely destroyed with the worst being that of Baghani, and another 47 that have some damage with the city of Khormoj having the most. Over 3000 households can be housed in emergency accommodation. So far it has been calculated that around 200 houses have major damage, thus less families are currently in accommodation.
With the cold weather, the main hope is to provide shelter for all people during the night, despite the ongoing aftershocks. Over 1000 tents have been transferred to the region. It is also hoped that the landslides have not engulfed any houses.
No damage has occurred in the oil fields of the Gulf, as well as Bahrain, Saudi Arabia, Dubai, Qatar and Kuwait. They did however have some shaking and it was well felt (thank you for all the felt reports). In addition, there were some high rise buildings that were evacuated as a precaution.
April 10, 2013
Update at 11:00 UTC - At least 40 people have died and 1000 people have been injured as a result of this earthquake according to current government figures. Over 100 of the 1000 injured have been severely injured.
|Depth||10 km (6.2 miles)|
|Distances||89 km (55 miles) SE of Bandar Bushehr, Iran|
92 km (57 miles) SSE of Borazjan, Iran
103 km (64 miles) WSW of Firuzabad, Iran
124 km (77 miles) S of Kazerun, Iran
|Location Uncertainty||horizontal +/- 14.2 km (8.8 miles); depth +/- 2.8 km (1.7 miles)|
|Parameters||NST=156, Nph=157, Dmin=>999 km, Rmss=0.76 sec, Gp= 25°,|
M-type=regional moment magnitude (Mw), Version=7
Tectonic summary by USGS
Seismotectonics of the Middle East and VicinityNo fewer than four major tectonic plates (Arabia, Eurasia, India, and Africa) and one smaller tectonic block (Anatolia) are responsible for seismicity and tectonics in the Middle East and surrounding region. Geologic development of the region is a consequence of a number of first-order plate tectonic processes that include subduction, large-scale transform faulting, compressional mountain building and crustal extension.
Mountain building in northern Pakistan and Afghanistan is the result of compressional tectonics associated with collision of the India plate moving northwards at a rate of 40 mm/yr with respect to the Eurasia plate. Continental thickening of the northern and western edge of the India subcontinent has produced the highest mountains in the world, including the Himalayan, Karakoram, Pamir and Hindu Kush ranges. Earthquake activity and faulting found in this region, as well as adjacent parts of Afghanistan and India, are due to collisional plate tectonics.
Beneath the Pamir-Hindu Kush Mountains of northern Afghanistan, earthquakes occur to depths as great as 200 km as a result of remnant lithospheric subduction. Shallower crustal earthquakes in the Pamir-Hindu Mountains occur primarily along the Main Pamir Thrust and other active Quaternary faults, which accommodate much of the region's crustal shortening. The western and eastern margins of the Main Pamir Thrust display a combination of thrust and strike-slip mechanisms.
Along the western margin of the Tibetan Plateau, in the vicinity of southeastern Afghanistan and western Pakistan, the India plate translates obliquely relative to the Eurasia plate, resulting in a complex fold-and-thrust belt known as the Sulaiman Range. Faulting in this region includes strike-slip, reverse-slip and oblique-slip motion and often results in shallow, destructive earthquakes. The relatively fast moving left-lateral, strike-slip Chaman Fault system in southeastern Afghanistan accommodates translational motion between the India and Eurasia plates. In 1505, a segment of the Chaman Fault system near Kabul, Afghanistan ruptured causing widespread destruction of Kabul and surrounding villages. In the same region, the more recent 30 May 1935, M7.6 Quetta, Pakistan earthquake, occurred within the Sulaiman Range, killing between 30,000 and 60,000 people.
Off the south coast of Pakistan and southeast coast of Iran, the Makran trench is the present-day surface expression of active subduction of the Arabia plate beneath the continental Eurasia plate, which converge at a rate of approximately 20 mm/yr. Although the Makran subduction zone has a relatively slow convergence rate, it has produced large devastating earthquakes and tsunamis. For example, the November 27, 1945 M8.0 mega-thrust earthquake produced a tsunami within the Gulf of Oman and Arabia Sea, killing over 4,000 people. Northwest of this active subduction zone, collision of the Arabia and Eurasia plates forms the approximately 1,500-km-long fold and thrust belt of the Zagros Mountains, which crosses the whole of western Iran and extends into northeastern Iraq. Collision of the Arabia and Eurasia plates also causes crustal shortening in the Alborz Mountains and Kopet Dag in northern Iran. Eastern Iran experiences destructive earthquakes that originate on both strike-slip and reverse faults. For example, the 16 September 1978 M7.8 earthquake, along the southwest edge of the Dasht-e-Lut Basin killed at least 15,000 people.
Along the eastern margin of the Mediterranean region there is complex interaction between the Africa, Arabia and Eurasia plates. The Red Sea Rift is a spreading center between the Africa and Arabia plates, with a spreading rate of approximately 10mm/yr near its northern end, and 16mm/yr near its southern end (Chu, D. and Gordon, R. G., 1998). Seismicity rate and size of earthquakes has been relatively small along the spreading center, but the rifting process has produced a series of volcanic systems across western Saudi Arabia.
Further north, the Red Sea Rift terminates at the southern boundary of the Dead Sea Transform Fault. The Dead Sea Transform is a strike-slip fault that accommodates differential motion between the Africa and Arabia plates. Though both the Africa plate, to the west, and the Arabia plate, to the east, are moving in a NNE direction, the Arabia plate is moving slightly faster, resulting in the left-lateral, strike-slip motion along this segment of the plate boundary. Historically, earthquake activity along the Dead Sea Transform has been a significant hazard in the densely populated Levant region (eastern Mediterranean). For example, the November 1759 Near East earthquake is thought to have killed somewhere between 2,000-20,000 people. The northern termination of the Dead Sea Transform occurs within a complex tectonic region of southeast Turkey, where interaction of the Africa and Arabia plates and the Anatolia block occurs. This involves translational motion of the Anatolia Block westwards, with a speed of approximately 25mm/yr with respect to Eurasia, in order to accommodate closure of the Mediterranean basin.
The right-lateral, strike-slip North Anatolia Fault, in northern Turkey, accommodates much of the westwards motion between the Anatolia Block and Eurasia Plate. Between 1939 and 1999, a series of devastating M7.0+ strike-slip earthquakes propagated westwards along the North Anatolia Fault system. The westernmost of these earthquakes was the 17th August 1999, M7.6 Izmit earthquake, near the Sea of Marmara, killed approximately 17,000 people.
At the southern edge of the Anatolia Block lies the east-west trending Cyprian Arc with associated levels of moderate seismicity. The Cyprian Arc represents the convergent boundary between the Anatolia Block to the north and the Africa Plate to the south. The boundary is thought to join the East Anatolia Fault zone in eastern Turkey; however no certain geometry or sense of relative motion along the entire boundary is widely accepted.
Featured image: USGS Shake Map