Author Topic: Tsunami warning 27 feb 2010  (Read 4180 times)

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Offline Colin Maitland

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Tsunami warning 27 feb 2010
« on: 28 February 2010, 04:35:38 PM »
Due to the severe earthquake magnitude 8.8 occurred at 4:34 PM EST on Saturday 27
February 2010 near THE COAST OF CENTRAL CHILE (latitude 35.320S longitude72.930W ) and the following  tremors, the Pacific area has been placed on alert, I have received an EWN warning as some of you may have also. Here is the report.

NSW is also on alert with much the same message except for localities.


MEDIA:
No use of the Standard Emergency Warning Signal (SEWS)
TOP PRIORITY FOR IMMEDIATE AND FREQUENT BROADCAST
********************************************************************************
TSUNAMI WARNING NUMBER 2 FOR QUEENSLAND
Issued by the Joint Australian Tsunami Warning Centre (JATWC) at
8:44 PM EST on Saturday 27 February 2010
********************************************************************************

TSUNAMI THREAT TO THE MARINE ENVIRONMENT

********************************************************************************
SUMMARY:
Tsunami warning for the marine environment for QUEENSLAND.

Threatened areas extend from Point Danger to Double Island Point, Moreton
Bay.

Possibility of dangerous waves, strong ocean currents and foreshore flooding
for several hours from 08:15 am (EST) Sunday.

Sea level observations HAVE confirmed a tsunami has been generated.

For further details visit the Bureau web site www.bom.gov.au.

Next update due by 10:14 PM EST on Saturday 27 February 2010
********************************************************************************
DETAILS:
Tsunami waves are more powerful than the same size beach waves, with the first
wave not always the largest. First tsunami effects are expected as follows:

Coolangatta after 08:15 am (EST) Sunday
Maroochydore after 09:00 am (EST) Sunday
Brisbane after 09:15 am (EST) Sunday

Do not go to the coast to watch the tsunami. Check that your neighbours have
received this advice.

Boats in harbours, estuaries or shallow coastal water should return to shore.
Secure your boat and move away from the waterfront. Vessels already at sea
should stay offshore in deep water until further advised.

Do not go to the coast to watch the tsunami, as there is the possibility of
dangerous, localised flooding of the immediate foreshore.

For emergency assistance, call EMERGENCY MANAGEMENT QUEENSLAND on 132 500

Maps showing the affected areas are on the Bureau web site
www.bom.gov.au/tsunami. For a repeat of this warning call 1300 TSUNAMI (1300
878 6264).
********************************************************************************
TSUNAMI SOURCE:
An undersea earthquake of magnitude 8.8 occurred at 4:34 PM EST on Saturday 27
February 2010 near THE COAST OF CENTRAL CHILE (latitude 35.320S longitude
72.930W )

Offline Richary

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Re: Tsunami warning 27 feb 2010
« Reply #1 on: 28 February 2010, 06:18:08 PM »
Luckily the Tsunami doesn't appear too big, and here in Sydney we are protected by NZ. From the Joint Tsunami Warning Centre update issued about 15 minutes ago....

AN EARTHQUAKE HAS OCCURRED WITH THESE PRELIMINARY PARAMETERS

 ORIGIN TIME -  0634Z 27 FEB 2010
 COORDINATES -  36.1 SOUTH   72.6 WEST
 DEPTH       -   55 KM
 LOCATION    -  NEAR COAST OF CENTRAL CHILE
 MAGNITUDE   -  8.8

MEASUREMENTS OR REPORTS OF TSUNAMI WAVE ACTIVITY

 GAUGE LOCATION        LAT   LON    TIME        AMPL         PER
 -------------------  ----- ------  -----  ---------------  -----
 EASTER CL            27.2S 109.5W  1160Z   0.44M /  1.4FT  08MIN
 ANCUD CL             41.9S  73.8W  0838Z   0.62M /  2.0FT  84MIN
 CALLAO LA-PUNTA PE   12.1S  77.2W  1029Z   0.36M /  1.2FT  30MIN
 ARICA CL             18.5S  70.3W  1008Z   0.94M /  3.1FT  42MIN
 IQUIQUE CL           20.2S  70.1W  0907Z   0.28M /  0.9FT  68MIN
 ANTOFAGASTA CL       23.2S  70.4W  0941Z   0.49M /  1.6FT  52MIN
 DART LIMA 32412      18.0S  86.4W  0941Z   0.24M /  0.8FT  36MIN
 CALDERA CL           27.1S  70.8W  0843Z   0.45M /  1.5FT  20MIN
 TALCAHUANO CL        36.7S  73.4W  0653Z   2.34M /  7.7FT  88MIN
 COQUIMBO CL          30.0S  71.3W  0852Z   1.32M /  4.3FT  30MIN
 CORRAL CL            39.9S  73.4W  0739Z   0.90M /  2.9FT  16MIN
 SAN FELIX CL         26.3S  80.1W  0815Z   0.53M /  1.7FT  08MIN
 VALPARAISO CL        33.0S  71.6W  0708Z   1.29M /  4.2FT  20MIN

 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 CONFIRM THAT A TSUNAMI HAS BEEN GENERATED
 WHICH COULD CAUSE WIDESPREAD DAMAGE. AUTHORITIES SHOULD TAKE
 APPROPRIATE ACTION IN RESPONSE TO THIS THREAT. THIS CENTER WILL
 CONTINUE TO MONITOR SEA LEVEL DATA TO DETERMINE THE EXTENT AND
 SEVERITY OF THE THREAT.

 A TSUNAMI IS A SERIES OF WAVES AND THE FIRST WAVE MAY NOT BE THE
 LARGEST. TSUNAMI WAVE HEIGHTS CANNOT BE PREDICTED AND CAN VARY
 SIGNIFICANTLY ALONG A COAST DUE TO LOCAL EFFECTS. THE TIME FROM
 ONE TSUNAMI WAVE TO THE NEXT CAN BE FIVE MINUTES TO AN HOUR, AND
 THE THREAT CAN CONTINUE FOR MANY HOURS AS MULTIPLE WAVES ARRIVE.

 FOR ALL 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.

ESTIMATED INITIAL TSUNAMI WAVE ARRIVAL TIMES AT FORECAST POINTS
WITHIN THE WARNING AND WATCH AREAS ARE GIVEN BELOW. ACTUAL
ARRIVAL TIMES MAY DIFFER AND THE INITIAL WAVE MAY NOT BE THE
LARGEST. A TSUNAMI IS A SERIES OF WAVES AND THE TIME BETWEEN
SUCCESSIVE WAVES CAN BE FIVE MINUTES TO ONE HOUR.

 AUSTRALIA        HOBART             43.3S 147.6E    2105Z 27 FEB
                  SYDNEY             33.9S 151.4E    2146Z 27 FEB
                  BRISBANE           27.2S 153.3E    2310Z 27 FEB
                  GLADSTONE          23.8S 151.4E    0101Z 28 FEB
                  CAIRNS             16.7S 145.8E    0159Z 28 FEB
                  MACKAY             21.1S 149.3E    0251Z 28 FEB



Offline Colin Maitland

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Re: Tsunami warning 27 feb 2010
« Reply #2 on: 01 March 2010, 01:59:48 AM »
JTWC and BOM have now placed the much of the east Coast of Australia, from Mackay to Tasmania on alert.

Although the wave heights do not appear too big from the  a list that has been generated by JTWC and posted below, it is important to remember that these heights are taken from Ocean Bouys and are measured by "Half peak to trough value".

Tsunamis have a small amplitude (wave height) offshore, and a very long wavelength often hundreds of kilometers long, which is why they generally pass unnoticed at sea, forming only a slight swell usually about 300 millimetres above the normal sea surface. They grow in height when they reach shallower water, in a wave shoaling process.
In shallow water and parallel depth contours, non-breaking waves will increase in wave height when following a wave packet as it moves from one location towards another location with less water depth. This is for instance particularly important with respect to the devastating effects of tsunamis  when they reach the coast.

Take care if near coastal waters.


PAPEETE TAHITI 17.5S 149.6W 1810Z 0.16M

RIKITEA FRENCH POLYNS 23.1S 134.9W 1559Z 0.15M

DART MARQUESAS 51406 8.5S 125.0W 1531Z 0.18M

CALDERA CHILE 27.1S 70.8W 0843Z 0.45M

TALCAHUANO CHILE 36.7S 73.4W 0653Z 2.34M

COQUIMBO CHILE 30.0S 71.3W 0852Z 1.32M

CORRAL CHILE 39.9S 73.4W 0739Z 0.90M

VALPARAISO CHILE 33.0S 71.6W 0708Z 1.29M

IQUIQUE CHILE 20.2S 70.1W 0907Z 0.28M

ANTOFAGASTA CHILE 23.2S 70.4W 0941Z 0.49M

ARICA CHILE 18.5S 70.3W 1007Z 0.94M

DART 32412 18.0S 86.4W 0941Z 0.24M

SAN FELIX CHILE 26.3S 80.1W 0815Z 0.53M

VALPARAISO CHILE 33.0S 71.6W 0708Z 1.29M

EASTER ISLAND 27.2S 109.5W 1205Z 0.35M

BALTRA GALAPAGOS IS 0.4S 90.3W 1452Z 0.35M

RARATONGA, COOK IS 21.2s 159.8E 1930z 0.35M
« Last Edit: 01 March 2010, 03:37:05 AM by Colin Maitland »