We've improved Slashdot's video section; now you can view our video interviews, product close-ups and site visits with all the usual Slashdot options to comment, share, etc. No more walled garden! It's a work in progress -- we hope you'll check it out (Learn more about the recent updates).
You are right. Arrive at the correct answer by multiplying the wrong value by another 1.5. Comes out to 830.4 tons of TNT. Which coincides with MichaelSmith's comment: "I saw another estimate of about a 1000 which is close enough."