Parts of the Indian Ocean have changed, and will need to be recharted, particluarly of the coast of Sumutra.
The area where the submarine was operating (some 560 kilometers (350 miles) south of Guam - at a depth of 120 meters (400 feet) ) should not have been affected by the Sumutran earthquake.
On the other hand, the Sumutran earthquake is a consequence of the dynamics of the earth's crust. It is an extension of the Pacific Ring of Fire where volcanic activity and earthquakes are quite common.
It would appear, as Russ stated, that some areas are not adequately mapped as they perhaps should be.