Update at 6:40 AM, Eastern:
NPR's Science correspondent Richard Harris has talked with civil defense authorities in Guam and a newspaper reporter in Saipan, in the Northern Marianas Islands. Residents of both islands headed for higher ground. No tsunami has struck, although buoys near Guam indicated a two foot wave off Guam.
Richard talked with Haidee Eugenio of the Saipan Tribune, who said there was a report of water 'ebbing' in the area, often a prelude to a tsunami, but none materialized.
The tsunami was supposed to arrive about two hours ago. Both Guam and the Marianas Islands have extended their tsunami warnings for another 90 minutes.
Update at 6:20 AM, Eastern:
Japan's Kyodo News Agency reports there's a fire at a nuclear power plant in Miyagi Prefecture. There's no indication any radiation has leaked. The website, Nuclear Engineering International says the Japanese government has launched its emergency protocol as all plants undergo safety inspections.
The U.S. Geological Survey says an 8.9 magnitude earthquake hit near Honshu, Japan mid-Friday afternoon, 12:46 AM eastern time. Reuters says it triggered a 30 foot tsunami that rolled over neighborhoods and farmlands. A fire is burning at an oil refinery and the country's nuclear power plants have been shut down.
The Pacific Tsunami Warning Center has issued a Severe Widespread Warning; authorities in Hawaii have ordered evacuations of the coast - a first tsunami wave may arrive there at 3 AM local time, or 8 AM Eastern time.