Background information:

• On Dec. 29, 2004 a very large 9 earthquake struck in the Indian Ocean.
• The earthquake was produced by perhaps 15 meters of slip along a 1200 km long segment by 100 km long (source). The area over which slip occurs determines the size of an earthquake. The hypocenter, the point of initiation was only 16 km deep, which is shallow.
• The earthquake occurred on an oblique subduction zone, a type of plate boundary known to be able to generate large earthquakes of the type that can also produce tsunamis.
• It caused large destructive waves called tsunamis that hit coastlines throughout the area.
• The wave swept over entire small islands, and inland in low lying coastal areas as much as two miles.
• The estimate of fatalities from both the tsunami and earthquake is now stabilizing around 150,000. As of this writing no one has attempted to come up with an estimate for loss of property.
• It was predictable, and in a sense was predicted.

• Simple when-to-run-away knowledge. There are precursors to the tsunamis arrival. The water withdraws from the shore more extensively and more quickly than during a normal tidal cycle. One must flee immediately for this warning to do any good.
• Simple knowledge that tsunamis come in multiples. If one tsunami comes in, even if small, stay away from the shore for at least several hours. The second or third wave can be even bigger.
• Identifying the nature of tsunami risk and zoning. An important part of identifying such risk is how often such an event might occur. A good estimate of the recurrence interval of this size earthquake can be made from looking at the history of past earthquakes in the area. A simple preliminary analysis using data off the web indicates that earthquakes of size 9 can be expected in the area every 600 years or less. Not all earthquakes produce tsunamis, and this would reduce the tsunami risk. But, tsunamis can be and have been caused by volcanic eruptions in the area (e.g. Krakatoa, and Tambora). The Krakatoa tsunamis killed 40,000 people. A list of other tsunamis in the area is given below. More frequent earthquakes greater than 7.9 magnitude are also capable of producing tsunamis (albeit smaller ones). Using computer models, historic behavior, data on topography and bathymetry, areas with significant tsunami risk can be identified. In those areas, people should not live and critical facilities such as hospitals should not be sited, and people should be informed about the risk and possible responses. Rebuilding should take this into consideration!!
• The installment of a tsunami warning system and education of people about proper response. One estimate is that such a system could cost circa ten million dollars - in hindsight a pittance. A tsunami warning system exists in the Pacific.

USGS compilation of tsunamis that had occurred in the area.

• " 1. 1797: A magnitude 8.4 earthquake near the central part of the western Sumatra generated a tsunami that flooded Padang. More than 300 fatalities.
• 2. 1833: A magnitude 8.7 earthquake near the south coast of the western Sumatra triggered a huge tsunami that flooded the southern part of western Sumatra. Numerous victims.
• 3. 1843: A tsunami that came from the southeast and flooded the coast of the Nias Island. Many fatalities.
• 4. 1861: A magnitude 8.5 earthquake affected all the western coast of Sumatra. Several thousand fatalities.
• 5. 1881: A magnitude 7.9 earthquake in the Andaman Island region generated a 1 m high tsunami on India's eastern coast. (http://cires.colorado.edu/~bilham/Oldham1881account.htm)
• 6. 1883: Krakatoa explosion. 36,000 fatalities, primarily on the islands of Java and Sumatra.
• 7. 1941: A magnitude ~7.7 Adaman Islands earthquake. Anecdotal accounts exist of a tsunami, however, no official records exist. "

Some conclusions:

• Globally, the largest payout for insurance companies year after year is for natural disasters, with flooding and earthquakes topping the list. We have the knowledge to prevent or mitigate much of the loss of life and property associated with natural disasters, but it is not being utilized to anywhere near its full extent.
• Earth science education is crucial, and can save and improve lives significantly.
• People have much greater difficulty dealing with the risk posed by rare but devastating events. It is very important to take a long term approach.

Further detailed information on the earthquake and tsunami from Columbia University.