Categorized | Earthquake, News

Strong earthquakes near Tonga and Samoa, no tsunami threat Sunday (March 29)

Earthquake epicenters on Sunday (March 29) between Tonga and Samoa.

Earthquake epicenters on Sunday (March 29) between Tonga and Samoa.


Magnitude
6.8

Event Time
2015-03-30 08:48:25 (UTC)
2015-03-29 22:48:25 HAST (Hawaii-Aleutian Standard Time)

Nearby Cities
99km (62mi) ENE of Hihifo, Tonga
226km (140mi) SSW of Apia, Samoa
272km (169mi) WSW of Tafuna, American Samoa
276km (171mi) WSW of Pago Pago, American Samoa
663km (412mi) NNE of Nuku`alofa, Tonga

TSUNAMI INFORMATION STATEMENT NUMBER 1
NWS PACIFIC TSUNAMI WARNING CENTER EWA BEACH HI
0902 UTC MON MAR 30 2015

...PTWC TSUNAMI INFORMATION STATEMENT...

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

  * MAGNITUDE      6.8
  * ORIGIN TIME    0848 UTC MAR 30 2015
  * COORDINATES    15.2 SOUTH  172.4 WEST
  * DEPTH          55 KM / 34 MILES
  * LOCATION       TONGA

EVALUATION
----------

  * AN EARTHQUAKE WITH A PRELIMINARY MAGNITUDE OF 6.8 OCCURRED IN
    THE TONGA ISLANDS AT 0848 UTC ON MONDAY MARCH 30 2015.

  * BASED ON ALL AVAILABLE DATA... THERE IS NO TSUNAMI THREAT
    FROM THIS EARTHQUAKE.

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

  * NO ACTION IS REQUIRED.

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

  * THIS WILL BE THE ONLY STATEMENT ISSUED FOR THIS EVENT UNLESS
    ADDITIONAL DATA ARE 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.

Magnitude
6.4

Event Time
2015-03-30 08:18:00 (UTC)
2015-03-29 22:18:00 HAST (Hawaii-Aleutian Standard Time)

Nearby Cities
109km (68mi) NE of Hihifo, Tonga
211km (131mi) SW of Apia, Samoa
262km (163mi) WSW of Tafuna, American Samoa
266km (165mi) WSW of Pago Pago, American Samoa
680km (423mi) NNE of Nuku`alofa, Tonga

TSUNAMI INFORMATION STATEMENT NUMBER 1
NWS PACIFIC TSUNAMI WARNING CENTER EWA BEACH HI
0827 UTC MON MAR 30 2015

...PTWC TSUNAMI INFORMATION STATEMENT...

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

  * MAGNITUDE      6.8
  * ORIGIN TIME    0818 UTC MAR 30 2015
  * COORDINATES    15.1 SOUTH  172.4 WEST
  * DEPTH          80 KM / 50 MILES
  * LOCATION       TONGA

EVALUATION
----------

  * AN EARTHQUAKE WITH A PRELIMINARY MAGNITUDE OF 6.8 OCCURRED IN
    THE TONGA ISLANDS AT 0818 UTC ON MONDAY MARCH 30 2015.

  * BASED ON ALL AVAILABLE DATA... THERE IS NO TSUNAMI THREAT
    FROM THIS EARTHQUAKE.

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

  * NO ACTION IS REQUIRED.

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

  * THIS WILL BE THE ONLY STATEMENT ISSUED FOR THIS EVENT UNLESS
    ADDITIONAL DATA ARE 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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