To: U.S. West Coast, Alaska, and British Columbia coastal regions
From: NOAA/NWS/West Coast and Alaska Tsunami Warning Center
Subject: Tsunami Warning and Advisory #4 issued 03/11/2011 at 12:51AM PST
The warning and advisory status regions have changed in this message.
The Tsunami Warning continues in effect for the coastal areas of California and Oregon from Point Concepcion, California to the Oregon-Washington border.
The Tsunami Warning continues in effect for the coastal areas of Alaska from Amchitka Pass, Alaska (125 miles W of Adak) to Attu, Alaska.
The Tsunami Advisory continues in effect for the coastal areas of California from the California-Mexico border to Point Concepcion, California.
The Tsunami Advisory continues in effect for the coastal areas of Washington, British Columbia and Alaska from the Oregon-Washington border to Amchitka Pass, Alaska (125 miles W of Adak).
A Tsunami Warning means that all coastal residents in the warning area who are near the beach or in low-lying regions should move immediately inland to higher ground and away from all harbors and inlets including those sheltered directly from the sea. Those feeling the earth shake, seeing unusual wave action, or the water level rising or receding may have only a few minutes before the tsunami arrival and should move immediately. Homes and small buildings are not designed to withstand tsunami impacts. Do not stay in these structures.
All residents within the warned area should be alert for instructions broadcast from their local civil authorities. A tsunami has been recorded.
A Tsunami Advisory means that a tsunami capable of producing strong currents or waves dangerous to persons in or very near the water is expected. Significant, widespread inundation is not expected for areas under an advisory. Currents may be hazardous to swimmers, boats, and coastal structures and may continue for several hours after the initial wave arrival.
At 9:46 PM Pacific Standard Time on March 10, an earthquake with preliminary magnitude 8.9 occurred near the east coast of Honshu, Japan . (Refer to the United States Geological Survey for official earthquake parameters.) This earthquake has generated a tsunami which could cause damage to coastal regions in a warning or advisory. The waves are expected to first reach Shemya, Alaska at 12:13 AM AKST on March 11. Estimated tsunami arrival times and maps along with safety rules and other information can be found on the WCATWC web site.
Measurements or reports of tsunami activity:
Location Lat. Lon. Time Amplitude
------------------------ ----- ------ ------- -----------
Tosashimizu Japan 32.8N 132.9E 0747UTC 00.9FT/00.27M
Tokai Japan 33.8N 137.6E 0645UTC 00.8FT/00.25M
Ofunato Japan 39.0N 141.8E 0605UTC 10.8FT/03.29M
Hanasaki Japan 43.3N 145.6E 0643UTC 09.3FT/02.82M
Boso Japan 34.8N 140.8E 0609UTC 02.6FT/00.78M
Time - Time of measurement.
Amp. - Tsunami amplitudes are measured relative to normal sea level. It is NOT crest-to-trough wave height. Values are given in both meters (M) and feet (FT).
DEEP OCEAN SENSORS INDICATE A LARGE TSUNAMI HAS BEEN GENERATED.
Tsunamis can be dangerous waves that are not survivable. Wave heights are amplified by irregular shoreline and are difficult to forecast. Tsunamis often appear as a strong surge and may be preceded by a receding water level. Mariners in water deeper than 600 feet should not be affected by a tsunami. Wave heights will increase rapidly as water shallows. Tsunamis are a series of ocean waves which can be dangerous for several hours after the initial wave arrival. DO NOT return to evacuated areas until an all clear is given by local civil authorities.
Pacific coastal regions outside California, Oregon, Washington, British Columbia, and Alaska should refer to the Pacific Tsunami Warning Center messages for information on the event.
This message will be updated in 60 minutes or sooner if the situation warrants. The tsunami message will remain in effect until further notice. For further information stay tuned to NOAA Weather Radio, your local TV or radio stations, or see the WCATWC web site.
