Yup, been thinking about this as well. I think the tank and stand would hold up, but maybe not hold upright... Maybe some flex braces to the wall wouldn't be a bad idea. But in the bigger picture, If the NW gets hit by a 9.0 and a huge tsunami, I'll just be happy to survive.
FYI: you may want to check your INS policy man. They may cover damges FROM your tank exploding and leaking all over, but in order for them to cover the CONTENTS of your tank(possibly thousands of dollars), you may need a special "declared/apraised item" type of addition to your policy. You'd be suprised what they wont pay you when its time to come through and its not in writing. Especially after a huge event like this thread is talking about.