A couple of mysterious booms Wednesday that rattled residents of the Port Angeles area seemed to be coming from the Strait of Juan de Fuca, but the cause remains undetermined. The Peninsula Daily News checked with the Clallam County sheriff's office, the Coast Guard, Navy, Joint Base Lewis-McChord, Canadian Forces and the Weather Service, and no one could account for Wednesday's unusual sounds. One resident, Michelle Kaake, heard two booms at her home. The first vibrated the floor and rattled the windows. She heard another one about five minutes later. The newspaper reports that loud booms have been reported occasionally on the north end of the Olympic Peninsula for the past nine years without explanation. Shallow earthquakes can cause loud booms, according to the U.S. Geological Survey website. "No one knows for sure, but scientists speculate that these 'booms' are probably small shallow earthquakes that are too small to be recorded," the USGS website said. But no earthquakes were