5.1ft amplitude at Midway in tsunami message 7
Posted by Chris in Tampa on 3/11/2011, 6:41 am
I think some confusion might be the amplitude compared to crest to trough height. (described below)


TSUNAMI MESSAGE NUMBER   7
NWS PACIFIC TSUNAMI WARNING CENTER EWA BEACH HI
133 AM HST FRI MAR 11 2011
TO - CIVIL DEFENSE IN THE STATE OF HAWAII
SUBJECT - TSUNAMI WARNING SUPPLEMENT
A TSUNAMI WARNING CONTINUES IN EFFECT FOR THE STATE OF HAWAII.
AN EARTHQUAKE HAS OCCURRED WITH THESE PRELIMINARY PARAMETERS
  ORIGIN TIME - 0746 PM HST 10 MAR 2011
  COORDINATES - 38.3 NORTH  142.4 EAST
  LOCATION    - NEAR EAST COAST OF HONSHU  JAPAN
  MAGNITUDE   - 8.9  MOMENT
MEASUREMENTS OR REPORTS OF TSUNAMI WAVE ACTIVITY
GAUGE LOCATION        LAT   LON    TIME        AMPL         PER
TOSASHIMIZU SHIKOKU  32.8N 133.0E  0946Z   0.84M /  2.8FT  28MIN
ADAK AK              51.9N 176.6W  1034Z   0.35M /  1.2FT  22MIN
YAP FM                9.5N 138.1E  1013Z   0.15M /  0.5FT  88MIN
LEGASPI PH           13.1N 123.8E  1022Z   0.29M /  1.0FT  **MIN
MIDWAY               28.2N 177.4W  1028Z   1.56M /  5.1FT  80MIN
DART 21415           50.2N 171.8E  0845Z   0.27M /  0.9FT  52MIN
WAKE US              19.3N 166.6E  0928Z   0.39M /  1.3FT  14MIN
NAHA OKINAWA JP      26.2N 127.7E  0901Z   0.25M /  0.8FT  60MIN
SAIPAN US            15.2N 145.7E  0916Z   0.65M /  2.1FT  30MIN
OMAEZAKI HONSHU JP   34.6N 138.2E  0818Z   1.42M /  4.6FT  56MIN
DART 21419           44.5N 155.7E  0716Z   0.40M /  1.3FT  20MIN
DART 21413           30.5N 152.1E  0659Z   0.76M /  2.5FT  32MIN
HANASAKI HOKKAIDO J  43.3N 145.6E  0657Z   2.79M /  9.2FT  76MIN
DART 21401           42.6N 152.6E  0643Z   0.67M /  2.2FT  40MIN
DART 21418           38.7N 148.7E  0619Z   1.08M /  3.5FT  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.
NOTE - DART MEASUREMENTS ARE FROM THE DEEP OCEAN AND THEY
       ARE GENERALLY MUCH SMALLER THAN WOULD BE COASTAL
        MEASUREMENTS AT SIMILAR LOCATIONS.
EVALUATION
A TSUNAMI HAS BEEN GENERATED THAT COULD CAUSE DAMAGE ALONG
COASTLINES OF ALL ISLANDS IN THE STATE OF HAWAII. URGENT ACTION
SHOULD BE TAKEN TO PROTECT LIVES AND PROPERTY.
A TSUNAMI IS A SERIES OF LONG OCEAN WAVES. EACH INDIVIDUAL WAVE
CREST CAN LAST 5 TO 15 MINUTES OR MORE AND EXTENSIVELY FLOOD
COASTAL AREAS. THE DANGER CAN CONTINUE FOR MANY HOURS AFTER THE
INITIAL WAVE AS SUBSEQUENT WAVES ARRIVE. TSUNAMI WAVE HEIGHTS
CANNOT BE PREDICTED AND THE FIRST WAVE MAY NOT BE THE LARGEST.
TSUNAMI WAVES EFFICIENTLY WRAP AROUND ISLANDS. ALL SHORES ARE AT
RISK NO MATTER WHICH DIRECTION THEY FACE. THE TROUGH OF A TSUNAMI
WAVE MAY TEMPORARILY EXPOSE THE SEAFLOOR BUT THE AREA WILL
QUICKLY FLOOD AGAIN. EXTREMELY STRONG AND UNUSUAL NEARSHORE
CURRENTS CAN ACCOMPANY A TSUNAMI. DEBRIS PICKED UP AND CARRIED
BY A TSUNAMI AMPLIFIES ITS DESTRUCTIVE POWER. SIMULTANEOUS HIGH
TIDES OR HIGH SURF CAN SIGNIFICANTLY INCREASE THE TSUNAMI HAZARD.
THE ESTIMATED ARRIVAL TIME IN HAWAII OF THE FIRST TSUNAMI WAVE IS
                    0307 AM HST FRI 11 MAR 2011
MESSAGES WILL BE ISSUED HOURLY OR SOONER AS CONDITIONS WARRANT.

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Historic Earthquake (modern era) #1 for Japan; #5 for the World - Tim_NC, 3/11/2011, 4:57 am
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