California officials this week launched an investigation into why sensors failed to trigger a tsunami warning in San Francisco after an earthquake hit offshore. A 7.2-magnitude earthquake, powerful enough to cause devastating sea surges, struck 80 miles off the Northern California coast last week. Warnings were issued from Canada down the West Coast of the U.S. to Mexico, but not in the San Francisco area. Annemarie Conroy, the citys emergency services director, said a parade of horribles including computer and communication glitches delayed a warning until it would have been too late to evacuate. Thank God it wasnt the real thing, Conroy said.