The Bam Earthquake

    On Friday, December 26, 2003 at 5:26am, Bam city in Southeastern Iran was jolted by an earthquake registering a 6.5 magnitude on the Richter scale. This was the result of the strike-slip motion of the Bam fault which runs through this area. The epicenter of the earthquake was determined to be approximately six miles southwest of the city. Three larger aftershocks as well as many smaller aftershocks were also recorded, the last of which occurred over a month after the main earthquake. Official death tolls to date have 26,271 fatalities, 9000 injured and 525 still missing. The city of Bam is one of Iranís most ancient cities, dating back to 224A.D. Latest reports and damage estimates are approaching the area of $1.9 billion. A United Nations report estimated that about 90% of the cityís buildings were 60%-100% damaged, while the remaining buildings were between 30%-60% damaged. Below is a map of the area and all the earthquakes and aftershocks detected over the month long time period.

    This area also showed several geotechnical aspects dealing with the earthquake. Ground fissures, which are highly common in areas of strike-slip faulting,  occurred all over the region. Below is a picture of a ground fissure taken after the Bam earthquake.

    The area also saw the effects of the collapse of Qanats, or underground irrigation systems which are highly common in Iran. A qanat is a system of water distribution that takes water from highland aquifers, and by the gravitational processes delivers water all over the lowlands. In Iran today, there are over 22,000 qanat units and over 170,000 miles of tunnels. This in turn provides nearly 75% of the country's water supply. Below is a picture of the area after one of these qanats collapses.

       Besides ground fissures and qanat collapses, the area was also prone to rockslides and rockfalls. The following picture shows a structure damaged after the ground supporting its foundation eroded away.