TSUNAMI INFORMATION STATEMENT NUMBER 1
NWS PACIFIC TSUNAMI WARNING CENTER EWA BEACH HI
0231 UTC WED NOV 1 2017
…PTWC TSUNAMI INFORMATION STATEMENT…
PRELIMINARY EARTHQUAKE PARAMETERS
* MAGNITUDE 6.8
* ORIGIN TIME 4:24 p.m. HST Tuesday, October 31, 2017
* COORDINATES 21.6 SOUTH 168.7 EAST
* DEPTH 14 KM / 9 MILES
* LOCATION LOYALTY ISLANDS
* AN EARTHQUAKE WITH A PRELIMINARY MAGNITUDE OF 6.8 OCCURRED IN
THE LOYALTY ISLANDS AT 4:24 p.m. HST Tuesday, October 31, 2017.
* BASED ON ALL AVAILABLE DATA… THERE IS NO TSUNAMI THREAT
FROM THIS EARTHQUAKE.
* 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/EARTHQUAKE… -ALL LOWER CASE-.
* 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
* 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
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.