December 26, 2004 at 7:58:53 local time a strong earthquake hit the island of Sumatra (Indonesia). It lasted unusual long with 8-10 minutes; however it caused only minor damage. The magnitude 9.1-9.3 earthquake had displaced an estimated 1.600 kilometres long segment of the seafloor by 15 metres, the water column above this segment was first pushed up and generated then a series of four waves travelling in opposite direction.

Video 1. The tsunami in the Indian Ocean is probably one of the most well documented natural disasters in modern history. “Tsunami: Caught on Camera” is a TV-documentary produced in 2009 using original footage (the video shows victims and injured people – viewers discretion is advised).

Fifteen minutes after the earthquake the first wave hit the coast of Sumatra without a warning. In Thailand it was the trough of the wave to approach first the coast. Videos show how the sea level first falls and large parts of the shores and even reefs emerge. Then suddenly a large single wave approaches, followed later by even faster and taller waves.

The waves travelled for 8 hours trough the entire Indian Ocean, bringing destruction and death to the coasts of Indonesia, Thailand, Sri Lanka, India, Somalia, Kenya, Tanzania, Madagascar and flooding almost completely the smaller islands in the Indian Ocean.
The Indonesian tsunami killed more than 230.000 people, possibly thousands of bodies remain either lost to the sea or unidentified and even more people were injured.

One year earlier, in the morning of December 26, 2003, the city of Bam in the Iranian province of Kerman was hit by 12 seconds lasting magnitude 6.5 earthquake.
The earthquake destroyed the mighty citadel of Arg-e-Bam, build during the reign of the Safawida-dynasty in the years 1501-1736. The citadel was constructed with bricks of clay and straw mortar like many buildings in the modern city. A typical building had a heavy roof of concrete resting on walls of simple bricks.
This type of construction is very unstable even during a moderate earthquake. In seconds 80% of the buildings in Bam collapsed, more than 26.000 people died and 120.000 people lost their homes.

Bibliography:

BARBER, A.J.; CROW, M.J. & MILSOM, J.S. ed. (2005): Sumatra – Geology, Resources and Tectonic Evolution. Geological Society Memoir No. 31: 304
BRYANT, E. (2008): Tsunami – The Underrated Hazard. 2.nd edition Springer: 338
KOZAK, J. & CERMAK, V. (2010): The Illustrated History of Natural Disasters. Springer-Verlag: 203
MANAFPOUR, A.R. (2004): The Bam, Iran earthquake of 26 December 2003 – Field Investigation Report. Halcrow-EEFIT Report: 59