Hurricanes, Tornadoes, Earthquakes, Disasters

[Myself °¿°]

Whoa! 7.9 Mag earthquake TONGA REGION...
Event Page

MAP 4.9 2009/03/20 02:10:38 -22.862 -174.802 35.0 TONGA REGION
MAP 5.3 2009/03/19 20:33:58 -23.290 -174.623 35.0 TONGA REGION
MAP 7.9 2009/03/19 18:17:40 -23.021 -174.700 34.0 TONGA REGION
MAP 5.0 2009/03/16 15:25:20 -20.651 -175.775 81.1 TONGA

10-degree Map Centered at 25°S,175°W

Depth 34 km (21.1 miles) set by location program

Tectonic Summary
The broad-scale tectonics of the earthquake region are dominated by the relative convergence of the Pacific and Australia plates. The Pacific plate subducts westward beneath the Australia plate at the Tonga trench. At the latitude of the earthquake, the Pacific plate moves westward with respect to the interior of the Australia plate at a velocity of about 77 mm/year. The eastern edge of the broad Australia plate may itself be viewed as a collection of small plates or microplates that move with respect to each other and with respect to the Pacific plate and the Australia plate interior. In terms of numbers of earthquakes, the broad-scale Australia/ Pacific plate boundary is one of the most active in the world. Earthquakes occur on the thrust-fault boundary between the Australia and Pacific plates, within the Pacific plate, and within and on the boundaries of the small plates that together compose the eastern edge of the overall Australia plate.


http://www.prh.noaa.gov/ptwc/?region=0
Tsunami warning center has it listed as 7.7

 
 TSUNAMI BULLETIN NUMBER 003 
 PACIFIC TSUNAMI WARNING CENTER/NOAA/NWS 
 ISSUED AT 2008Z 19 MAR 2009 
  
 THIS BULLETIN APPLIES TO AREAS WITHIN AND BORDERING THE PACIFIC 
 OCEAN AND ADJACENT SEAS...EXCEPT ALASKA...BRITISH COLUMBIA... 
 WASHINGTON...OREGON AND CALIFORNIA. 
  
 ... TSUNAMI WARNING CANCELLATION ... 
  
 THE TSUNAMI WARNING AND/OR WATCH ISSUED BY THE PACIFIC TSUNAMI 
 WARNING CENTER IS NOW CANCELLED FOR 
  
  TONGA / NIUE / KERMADEC IS / AMERICAN SAMOA / SAMOA / 
  WALLIS-FUTUNA / FIJI 
  
 THIS BULLETIN IS ISSUED AS ADVICE TO GOVERNMENT AGENCIES.  ONLY 
 NATIONAL AND LOCAL GOVERNMENT AGENCIES HAVE THE AUTHORITY TO MAKE 
 DECISIONS REGARDING THE OFFICIAL STATE OF ALERT IN THEIR AREA AND 
 ANY ACTIONS TO BE TAKEN IN RESPONSE. 
  
 AN EARTHQUAKE HAS OCCURRED WITH THESE PRELIMINARY PARAMETERS 
  
  ORIGIN TIME -  1818Z 19 MAR 2009 
  COORDINATES -  23.0 SOUTH  174.8 WEST 
  DEPTH       -   10 KM 
  LOCATION    -  TONGA ISLANDS REGION 
  MAGNITUDE   -  7.7 
  
 MEASUREMENTS OR REPORTS OF TSUNAMI WAVE ACTIVITY 
  
  GAUGE LOCATION        LAT   LON    TIME        AMPL         PER 
  -------------------  ----- ------  -----  ---------------  ----- 
  NIUE                 19.1S 169.9W  1911Z   0.04M /  0.1FT  06MIN 
  
  LAT  - LATITUDE (N-NORTH, S-SOUTH) 
  LON  - LONGITUDE (E-EAST, W-WEST) 
  TIME - TIME OF THE MEASUREMENT (Z IS UTC IS GREENWICH TIME) 
  AMPL - TSUNAMI AMPLITUDE MEASURED RELATIVE TO NORMAL SEA LEVEL. 
         IT IS ...NOT... CREST-TO-TROUGH WAVE HEIGHT. 
         VALUES ARE GIVEN IN BOTH METERS(M) AND FEET(FT). 
  PER  - PERIOD OF TIME IN MINUTES(MIN) FROM ONE WAVE TO THE NEXT. 
  
 EVALUATION 
  
  SEA LEVEL READINGS INDICATE A TSUNAMI WAS GENERATED. IT MAY HAVE 
  BEEN DESTRUCTIVE ALONG COASTS NEAR THE EARTHQUAKE EPICENTER. FOR 
  THOSE AREAS - WHEN NO MAJOR WAVES ARE OBSERVED FOR TWO HOURS 
  AFTER THE ESTIMATED TIME OF ARRIVAL OR DAMAGING WAVES HAVE NOT 
  OCCURRED FOR AT LEAST TWO HOURS THEN LOCAL AUTHORITIES CAN ASSUME 
  THE THREAT IS PASSED. DANGER TO BOATS AND COASTAL STRUCTURES CAN 
  CONTINUE FOR SEVERAL HOURS DUE TO RAPID CURRENTS. AS LOCAL 
  CONDITIONS CAN CAUSE A WIDE VARIATION IN TSUNAMI WAVE ACTION THE 
  ALL CLEAR DETERMINATION MUST BE MADE BY LOCAL AUTHORITIES. 
  
  NO TSUNAMI THREAT EXISTS FOR OTHER COASTAL AREAS IN THE PACIFIC 
  ALTHOUGH SOME OTHER AREAS MAY EXPERIENCE SMALL SEA LEVEL CHANGES. 
  THE TSUNAMI WARNING IS NOW CANCELLED FOR ALL AREAS COVERED BY 
  THIS CENTER. 
  
 THIS WILL BE THE FINAL BULLETIN ISSUED FOR THIS EVENT UNLESS 
 ADDITIONAL INFORMATION BECOMES AVAILABLE. 
  
 THE WEST COAST/ALASKA TSUNAMI WARNING CENTER WILL ISSUE PRODUCTS 
 FOR ALASKA...BRITISH COLUMBIA...WASHINGTON...OREGON...CALIFORNIA. 
 __________________________________________________________________________

TSUNAMI MESSAGE NUMBER   3 
 NWS PACIFIC TSUNAMI WARNING CENTER EWA BEACH HI 
 1009 AM HST THU MAR 19 2009 
  
 TO - CIVIL DEFENSE IN THE STATE OF HAWAII 
  
 SUBJECT - FINAL TSUNAMI ADVISORY 
  
 THE TSUNAMI ADVISORY IS ENDED FOR THE STATE OF HAWAII EFFECTIVE 
 AT 1009 AM HST. 
  
 AN EARTHQUAKE HAS OCCURRED WITH THESE PRELIMINARY PARAMETERS 
  
    ORIGIN TIME - 0818 AM HST 19 MAR 2009 
    COORDINATES - 23.0 SOUTH  174.8 WEST 
    LOCATION    - TONGA ISLANDS REGION 
    MAGNITUDE   - 7.7  MOMENT 
  
 MEASUREMENTS OR REPORTS OF TSUNAMI WAVE ACTIVITY 
  
  GAUGE LOCATION        LAT   LON    TIME        AMPL         PER 
  -------------------  ----- ------  -----  ---------------  ----- 
  NIUE                 19.1S 169.9W  1911Z   0.04M /  0.1FT  06MIN 
  
  LAT  - LATITUDE (N-NORTH, S-SOUTH) 
  LON  - LONGITUDE (E-EAST, W-WEST) 
  TIME - TIME OF THE MEASUREMENT (Z IS UTC IS GREENWICH TIME) 
  AMPL - TSUNAMI AMPLITUDE MEASURED RELATIVE TO NORMAL SEA LEVEL. 
         IT IS ...NOT... CREST-TO-TROUGH WAVE HEIGHT. 
         VALUES ARE GIVEN IN BOTH METERS(M) AND FEET(FT). 
  PER  - PERIOD OF TIME IN MINUTES(MIN) FROM ONE WAVE TO THE NEXT. 
  
 EVALUATION 
  
  THE PACIFIC TSUNAMI WARNING CENTER HAS CANCELLED THE REGIONAL 
  TSUNAMI WARNING IT ISSUED FOR ANOTHER PART OF THE PACIFIC. BASED 
  ON ALL AVAILABLE DATA THERE IS NO DESTRUCTIVE TSUNAMI THREAT TO 
  HAWAII AND THE ADVISORY FOR HAWAII IS ALSO CANCELLED. 
  
  HOWEVER... SOME COASTAL AREAS IN HAWAII COULD EXPERIENCE SMALL 
  NON-DESTRUCTIVE SEA LEVEL CHANGES AND STRONG OR UNUSUAL CURRENTS 
  LASTING UP TO SEVERAL HOURS. THE ESTIMATED TIME SUCH EFFECTS 
  MIGHT BEGIN IS 
  
                      0236 PM HST THU 19 MAR 2009 
  
 THIS WILL BE THE FINAL MESSAGE ISSUED FOR THIS EVENT UNLESS 
 ADDITIONAL DATA ARE RECEIVED.

_______________________________________________________________________________
http://wcatwc.arh.noaa.gov/
http://wcatwc.arh.noaa.gov/2009/03/19/748666/01/message748666-01.htm
To: U.S. West Coast, Alaska, and British Columbia coastal regions
From: NOAA/NWS/West Coast and Alaska Tsunami Warning Center
Subject: Tsunami Information Statement #1 issued 03/19/2009 at 11:30AM PDT

A strong earthquake has occurred, but a tsunami IS NOT expected along the California, Oregon, Washington, British Columbia, or Alaska coast. NO tsunami warning, watch or advisory is in effect for these areas.

Based on the earthquake magnitude, location and historic tsunami records, a damaging tsunami IS NOT expected along the California, Oregon, Washington, British Columbia, and Alaska coasts. At coastal locations which have experienced strong ground shaking, local tsunamis are possible due to underwater landslides.

At 11:18 AM Pacific Daylight Time on March 19, an earthquake with preliminary magnitude 7.7 occurred in the Tonga Islands region. (Refer to the United States Geological Survey for official earthquake parameters.)

The Pacific Tsunami Warning Center in Ewa Beach, Hawaii will issue a tsunami warning for regions near the epicenter.

This will be the only statement issued for this event by the West Coast/Alaska Tsunami Warning Center unless conditions warrant. See the WCATWC web site for basic tsunami information,safety rules, and a tsunami travel time map and table. (NOTE: Travel time maps and tables indicate forecasted times only, not that a wave was generated.)

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