Those areas were doubly cursed. It is apparent that the entire area is very low lying, with much development made via levees and landfill. When the earthquake hit, there must have been lots of liquifaction, destroying foundations and undermining roads, not to mention causing failure of some of the levees. Then, when the tsunami hit, the normal protective structures were not at full strength, even in cases where they were not overtopped. The final insult to injury was the return flow. What a mess.
bump for future reference
As I understand it, the island of Sumatra (I think it was that one) was pushed 100 feet to the southwest by the water. The ENTIRE ISLAND! It altered the core of the earth and compressed it as well, so now the earth rotates a little faster, like an iceskater drawing their arms in during a spin to spin faster! Truly an event of Biblical proportions to say the least!