Bam Earthquake of 26 December 2003, Mw=6.5

Bam Earthquake of 26 December 2003, Mw=6.5

Twelve years ago on December 26, 2003, a catastrophic earthquake of magnitude Mw=6.5 occurred in the ancient city of Bam in Iran at 5:26:26 a.m. local time, (1:26:26 GMT). The epicenter of the earthquake was located within the city of Bam at the coordination of 29.04N and 58.33E.

The city of Bam is located in southeast of Iran in the western margin of the Lut tectonic block. The city is located right next to the Bam fault which is a north-south oriented fault with 65 km length. Based on the NEIC and Harvard CMT catalog, the earthquake was occurred by the Bam fault activity with a right-lateral strike-slip mechanism. It is notable that historic seismicity reports no considerable earthquake within the affected area, because the 2,000-year-old Arg-e-Bam citadel had remained intact until the 2003 event. It seems that the region had faced a seismic gap which ended by the December 26, 2003 earthquake.

There are 27 accelerograms of the event recorded by the Iran Strong Motion Network (ISMN) among which the accelerograph of the “Bam” station has recorded a maximum 0.98g acceleration in the vertical component. The station was located in the epicentral distance of 6 km which implies a near-fault directivity effect in the vertical direction.

Based on the field investigations, the earthquake intensity was assessed to be about IX in the city of Bam, VIII in the city of Baravat and IV-V in the cities of Kerman and Mahan. Extensive and severe damages were emerged by the earthquake occurrence in Bam where houses and public places such as banks, firefighting, hospitals, buildings of the red crescent and many critical infrastructure were heavily damaged. The three cities of Baravat, Fahraj and Rigan and 250 villages were also damaged between 10% to 100%. In addition to the physical damages, the earthquake was associated with large human death and injuries and psychological, mental and social consequences. The time of the earthquake occurrence in the morning and its shallow depth intensified the consequences. In fact, the 2003 Bam earthquake is the most catastrophic earthquake during the last century which left 33,000 causalities, 50,000 injuries, 100,000 homeless and more than 500 children with spinal cord. After the event, the day December 26 was officially registered in the Iran’s national calendar as the “national safety day against earthquake”.

The most important worldwide earthquakes (M>7) on this day