Hawaii County Civil Defense audio message

Magnitude
7.0

Time
2015-07-18 02:27:33 (UTC)
2015-07-17 16:27:33 HST

Nearby Cities
78km (48mi) WNW of Lata, Solomon Islands
583km (362mi) ESE of Honiara, Solomon Islands
603km (375mi) NNW of Luganville, Vanuatu
875km (544mi) NNW of Port-Vila, Vanuatu
1159km (720mi) ESE of Arawa, Papua New Guinea

TSUNAMI MESSAGE NUMBER 2
NWS PACIFIC TSUNAMI WARNING CENTER EWA BEACH HI
0259 UTC SAT JUL 18 2015

...PTWC FINAL TSUNAMI THREAT MESSAGE...

NOTE REVISED EARTHQUAKE MAGNITUDE

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

  * MAGNITUDE      6.9
  * ORIGIN TIME    0228 UTC JUL 18 2015
  * COORDINATES    10.3 SOUTH  165.2 EAST
  * DEPTH          33 KM / 20 MILES
  * LOCATION       SANTA CRUZ ISLANDS

EVALUATION
----------

  * AN EARTHQUAKE WITH A PRELIMINARY MAGNITUDE OF 6.9 OCCURRED IN
    THE SANTA CRUZ ISLANDS AT 0228 UTC ON SATURDAY JULY 18 2015.

  * BASED ON ALL DATA AVAILABLE TO THIS CENTER... THE TSUNAMI
    THREAT FROM THIS EARTHQUAKE HAS NOW MOSTLY PASSED. ANY
    REMAINING THREAT SHOULD BE EVALUATED BY LOCAL AUTHORITIES IN
    IMPACTED AREAS.

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

  * THERE IS NO LONGER A TSUNAMI THREAT FROM THIS EARTHQUAKE.

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

  * REMAIN OBSERVANT AND EXERCISE NORMAL CAUTION NEAR THE SEA.
    OTHERWISE... NO ACTION IS REQUIRED.

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.

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.