Categorized | Earthquake, News, Tsunami

Very strong 7.9M quake in Papua New Guinea, no tsunami threat

TSUNAMI MESSAGE NUMBER 4
NWS PACIFIC TSUNAMI WARNING CENTER EWA BEACH HI
1255 UTC SAT DEC 17 2016

...PTWC FINAL TSUNAMI THREAT MESSAGE...

THE TSUNAMI FORECAST IS UNCHANGED IN THIS MESSAGE.


PRELIMINARY EARTHQUAKE PARAMETERS
---------------------------------

  * MAGNITUDE      7.9
  * ORIGIN TIME    1051 UTC DEC 17 2016
  * COORDINATES    4.5 SOUTH  153.6 EAST
  * DEPTH          73 KM / 46 MILES
  * LOCATION       NEW IRELAND REGION  PAPUA NEW GUINEA


EVALUATION
----------

  * AN EARTHQUAKE WITH A PRELIMINARY MAGNITUDE OF 7.9 OCCURRED IN
    THE NEW IRELAND REGION, PAPUA NEW GUINEA AT 1051 UTC ON
    SATURDAY DECEMBER 17 2016.

  * BASED ON ALL AVAILABLE DATA... THE TSUNAMI THREAT FROM THIS
    EARTHQUAKE HAS NOW PASSED.


TSUNAMI THREAT FORECAST...UPDATED
---------------------------------

  * THE TSUNAMI THREAT HAS NOW LARGELY PASSED.


RECOMMENDED ACTIONS
-------------------

  * GOVERNMENT AGENCIES RESPONSIBLE FOR ANY IMPACTED COASTAL
    AREAS SHOULD MONITOR CONDITIONS AT THE COAST TO DETERMINE IF
    AND WHEN IT IS SAFE TO RESUME NORMAL ACTIVITIES.

  * PERSONS LOCATED NEAR IMPACTED COASTAL AREAS SHOULD STAY ALERT
    FOR INFORMATION AND FOLLOW INSTRUCTIONS FROM LOCAL
    AUTHORITIES.

  * REMAIN OBSERVANT AND EXERCISE NORMAL CAUTION NEAR THE SEA.


POTENTIAL IMPACTS
-----------------

  * MINOR SEA LEVEL FLUCTUATIONS OF UP TO 0.3 METERS ABOVE AND
    BELOW THE NORMAL TIDE MAY CONTINUE OVER THE NEXT FEW HOURS.


TSUNAMI OBSERVATIONS
--------------------

  * THE FOLLOWING ARE TSUNAMI WAVE OBSERVATIONS FROM COASTAL
    AND/OR DEEP-OCEAN SEA LEVEL GAUGES AT THE INDICATED
    LOCATIONS. THE MAXIMUM TSUNAMI HEIGHT IS MEASURED WITH
    RESPECT TO THE NORMAL TIDE LEVEL.

                            GAUGE      TIME OF   MAXIMUM     WAVE
                         COORDINATES   MEASURE   TSUNAMI   PERIOD
    GAUGE LOCATION        LAT   LON     (UTC)     HEIGHT    (MIN)
    -------------------------------------------------------------
    TAREKUKURE WHARF SB   6.7S 156.4E    1243   0.08M/ 0.3FT  24
    DART 55023           14.7S 153.5E    1230   0.005M/0.016FT 12


NEXT UPDATE AND ADDITIONAL INFORMATION
--------------------------------------

  * THIS WILL BE THE FINAL STATEMENT ISSUED FOR THIS EVENT UNLESS
    NEW INFORMATION IS RECEIVED OR THE SITUATION CHANGES.

  * AUTHORITATIVE INFORMATION ABOUT THE EARTHQUAKE FROM THE U.S.
    GEOLOGICAL SURVEY CAN BE FOUND ON THE INTERNET AT
    EARTHQUAKE.USGS.GOV/EARTHQUAKES -ALL LOWER CASE-.

  * FURTHER INFORMATION ABOUT THIS EVENT MAY BE FOUND AT
    PTWC.WEATHER.GOV AND AT WWW.TSUNAMI.GOV.

  * COASTAL REGIONS OF HAWAII... AMERICAN SAMOA... GUAM... AND
    CNMI SHOULD REFER TO PACIFIC TSUNAMI WARNING CENTER MESSAGES
    SPECIFICALLY FOR THOSE PLACES THAT CAN BE FOUND AT
    PTWC.WEATHER.GOV.

  * COASTAL REGIONS OF CALIFORNIA... OREGON... WASHINGTON...
    BRITISH COLUMBIA AND ALASKA SHOULD ONLY REFER TO U.S.
    NATIONAL TSUNAMI WARNING CENTER MESSAGES THAT CAN BE FOUND
    AT NTWC.ARH.NOAA.GOV.

USGS: How large does an earthquake have to be to cause a tsunami?

Magnitudes below 6.5
Earthquakes of this magnitude are very unlikely to trigger a tsunami.

Magnitudes between 6.5 and 7.5
Earthquakes of this size do not usually produce destructive tsunamis. However, small sea level changes may be observed in the vicinity of the epicenter. Tsunamis capable of producing damage or casualties are rare in this magnitude range but have occurred due to secondary effects such as landslides or submarine slumps.

Magnitudes between 7.6 and 7.8
Earthquakes of this size may produce destructive tsunamis especially near the epicenter; at greater distances small sea level changes may be observed. Tsunamis capable of producing damage at great distances are rare in the magnitude range.

Magnitude 7.9 and greater
Destructive local tsunamis are possible near the epicenter, and significant sea level changes and damage may occur in a broader region.

Note that with a magnitude 9.0 earthquake, the probability of an aftershock with a magnitude exceeding 7.5 is not negligible. To date, the largest aftershock recorded has been magnitude 7.1 that did not produce a damaging tsunami.

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