dr. richard allen i believe has spoken before from uc berkley is going to give us an update we've partnered with the sxhifkal lab hello dr. allen. >> just what is an early warning it's about dektd the beginning of an earthquake and the amount of shaking and pushing that warning out to people in harm's way the idea the earthquake has started and seconds tens of seconds a best-case scenario is seconds in advance we've tested the shake alert the system has been running end to end since 2012 and we've been partnering with the city with ann for the entire duration of the project. so how did the system do in the napa earthquake i'm going to show you a quick video of an alert that was received in san francisco, california you get that video? >> ♪ ♪ kweerth earthquake ligament shaking expected in two seconds >> so as you can see it is a short warning 8 seconds between when the alert was pushed out and the shaking actively occurred it's telling you how many shaking in synthetical circulations it's light, of course, it's stronger in napa but this is a success story of (siren). earthquake earthquake a