Survivors in indonesia after a massive tsunami struck sunday without any warning. you can see in this video posted on social media concertgoers caught off guard as a wave sweeps through. just some of the discharge captured on camera. more than 370 people killed in the tsunami and dozens are still missing. nbc's sarah harman joins us on the ground from indonesia. let's talk a little bit about why the tsunami warning system that country is known to have did not work, what have you learned so far? >> reporter: hey, good morning. so far we've learned that this tsunami was not triggered by an earth...