the earthquake takes 100 seconds to unzip. so this earthquake didn't happen all at once like you might think. the fault unzipped over a period of 100 seconds, and during those 100 seconds, we have a pretty complicated pattern of shake, so that's what your eyewitness reporters are telling us and we can confirm that request the seismographs and the equipment that records the earthquakes. >> i know you're not a sooth sayer, but our resident colleague predicts that we'll have one of these huge earthquakes on the west coast of the united states in our lifetime. and what's the official position of the u.s. geological survey. >> i can give you a clear answer on that. the last earthquake of this size that occurred in the united states was in 1700 in january. and we know that well from the records of the tsunami that