Tsunami-interesting article

[1Gary]

Tsunami racing toward California, Oregon and Washington
by barnsey on Fri Mar 11, 2011 11:48 pm

The National Weather Service(NWS) has issued a tsunami or tidal wave warning for Hawaii and the entire west coast of the United States. The warning comes in response to a magnitude 8.9 earthquake that jolted Japan early this morning.

The tsunami, say the National Oceanic and Atmospheric Administration (NOAA)is expected to begin arriving on the west coast at approximately 7:10 am PST, in Washington and Oregon. Within minutes the wave, moving from west to east, will begin impacting California. Hawaii is expected to see the leading edge of the tsunami just before 3:00 am local time.

The peak height of the water is measured in terms of height above normal sea level, not peak to trough level. The popular notion that the initial wave strike is the most dangerous part of the tsunami is not true according to the NWS. The NWS says tsunamis strike as a series of waves with the strongest often coming later in the series.

Each wave can force more water inland, much like an extraordinary tide or storm surge rushing in. The exact height of the wave is difficult to predict because it is highly dependent upon the topography of the coasts in its path.

The wave has already started to impact Alaska with an amplitude or height of 3.5 feet above normal sea level recorded at Shemya, Alaska. At present, the highest tsunami amplitude was recorded at Ofunato, Japan shortly after the earthquake that triggered the massive waves. In Ofunato, says the NWS, the wave measured as much as 10.7 feet above the normal sea level.

Boats along the coast of Japan were capsized and cars were swept from the roads by the inrushing tsunami waters. Casualties, including deaths have been reported from Japan, although it may be some time before accurate numbers can be given. Aftershocks continue to shake Tokyo and are expected to continue throughout the day.

The earthquake’s magnitude of 8.9 on the Richter Scale makes it one of the top 5 most powerful earthquakes of the last 100 years. It was centered at a depth of 12 miles off the coast of Honshu, Japan says the NWS. At this point, the west coast is under a tsunami warning, meaning that “a tsunami with significant widespread inundation is imminent or expected. Warnings indicate that widespread dangerous coastal flooding accompanied by powerful currents is possible and may continue for several hours after the initial wave arrival.”

Persons in coastal or low-lying areas within a tsunami warning zone should move immediately inland to higher ground away from all harbors and inlets including those sheltered directly fromt he sea, says the NWS. The imminient arrival of the tsunami may be preceded by the ground shaking or rapidly rising or falling water levels. The NWS further warns that small buildings do not represent protection from a tsunami as they are not designed to wiithstand such an event. Residents in an affected area should seek specific direction from local civil authorities.



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[MountainManJoe]

The tsunami, say the National Oceanic and Atmospheric Administration (NOAA)is expected to begin arriving on the west coast at approximately 7:10 am PST, in Washington and Oregon.

That was 2 hrs ago. Any news from our US west coast members?

Gary, your link is broken.

[1Gary]

TB-this is a open thread.If anyone wants to add info-please do.I've been busy working in the shop.