Categorized | Earthquake, News, Tsunami

Severe 8.1M earthquake near Mexico, no tsunami threat to Hawaii


Hawaii County Civil Defense audio message

TSUNAMI MESSAGE NUMBER 17
NWS PACIFIC TSUNAMI WARNING CENTER EWA BEACH HI
1826 UTC FRI SEP 8 2017

...PTWC FINAL TSUNAMI THREAT MESSAGE...

THE TSUNAMI FORECAST IS UNCHANGED IN THIS MESSAGE.


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

  * MAGNITUDE      8.2
  * ORIGIN TIME    0449 UTC SEP 8 2017
  * COORDINATES    14.9 NORTH  94.0 WEST
  * DEPTH          33 KM / 20 MILES
  * LOCATION       OFF THE COAST OF CHIAPAS  MEXICO


EVALUATION
----------

  * AN EARTHQUAKE WITH A PRELIMINARY MAGNITUDE OF 8.2 OCCURRED
    OFF THE COAST OF CHIAPAS, MEXICO AT 0449 UTC ON FRIDAY
    SEPTEMBER 8 2017.

  * 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)
    -------------------------------------------------------------
    APIA UPOLU WS        13.8S 171.8W    1759   0.22M/ 0.7FT  14
    PAGO PAGO AS         14.3S 170.7W    1726   0.12M/ 0.4FT  22
    PAPEETE TAHITI       17.5S 149.6W    1508   0.04M/ 0.1FT  18
    QUEPOS CR             9.4N  84.2W    1345   0.17M/ 0.6FT  88
    LA LIBERTAD SV       13.5N  89.3W    1137   0.19M/ 0.6FT  74
    ACAJUTLA SV          13.6N  89.8W    1537   0.47M/ 1.5FT  20
    CHIAPAS MX           14.7N  92.4W    0949   1.75M/ 5.8FT  32
    KAHULUI MAUI         20.9N 156.5W    1413   0.18M/ 0.6FT  18
    HILO HAWAII          19.7N 155.1W    1357   0.17M/ 0.6FT  18
    HIVA OA MARQUESAS     9.8S 139.0W    1341   0.18M/ 0.6FT  08
    NUKU HIVA MARQUESAS   8.9S 140.1W    1306   0.20M/ 0.7FT  14
    DART 32412           18.0S  86.4W    1020   0.01M/ 0.0FT  26
    EASTER CL            27.2S 109.4W    1151   0.29M/ 0.9FT  06
    DART 32413            7.4S  93.5W    0843   0.02M/ 0.1FT  24
    LAZARO CARDENAS MX   17.9N 102.2W    0646   0.20M/ 0.6FT  58
    DART 43413           10.8N 100.1W    0558   0.07M/ 0.2FT  10
    SANTACRUZ GALAPAGOS   0.7S  90.3W    0835   0.15M/ 0.5FT  20
    ZIHUATANEJO MX       17.6N 101.6W    0627   0.21M/ 0.7FT  50
    BALTRA GALAPAGS EC    0.4S  90.3W    0806   0.17M/ 0.5FT  26
    MANZANILLO MX        19.1N 104.3W    0710   0.24M/ 0.8FT  38
    ACAPULCO MX          16.8N  99.9W    0635   0.72M/ 2.4FT  24
    DART 32411            5.0N  90.8W    0642   0.03M/ 0.1FT  26
    SALINA CRUZ MX       16.2N  95.2W    0635   1.01M/ 3.3FT  46
    PUERTO ANGEL MX      15.7N  96.5W    0517   0.29M/ 1.0FT  24
    HUATULCO MX          15.8N  96.1W    0514   0.69M/ 2.3FT  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.


An animation of the energy from the magnitude of 8.2 earthquake occurred off the coast of Chiapas, Mexico at 06:49 p.m. HST on Thursday, September 7, 2017. Animation courtesy of European Commission JRC.

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.

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.

 

 

Become a fan on facebook

 

 

Quantcast
%d bloggers like this: