ShakeAlert, an earthquake early-warning system, will be active in Oregon next month, giving crucial seconds of advance warning to allow people and systems to take action from destructive shaking and possible tsunami. The system, which delivers alerts to wireless devices such as cell phones through the Wireless Emergency Alert system, apps and other technologies, will begin at 10 a.m. March 11, the Oregon Office of Emergency Management announced Thursday. What does it do? When the network of seismic sensors across California, Oregon and Washington detect shaking, ShakeAlert issues a message containing information about the estimated magnitude and area of shaking caused by the quake.