Magnitude
6.4
Time
2015-04-20 01:42:58 (UTC)
2015-04-19 15:42:58 HAST (Hawaii-Aleutian Standard Time)
Nearby Cities
66km (41mi) SE of Su’ao, Taiwan
77km (48mi) ENE of Hualian, Taiwan
85km (53mi) SE of Yilan, Taiwan
119km (74mi) SSE of Keelung, Taiwan
862km (536mi) ENE of Hong Kong, Hong Kong
TSUNAMI INFORMATION STATEMENT NUMBER 1
NWS PACIFIC TSUNAMI WARNING CENTER EWA BEACH HI
0149 UTC MON APR 20 2015
…PTWC TSUNAMI INFORMATION STATEMENT…
PRELIMINARY EARTHQUAKE PARAMETERS
———————————
* MAGNITUDE 6.6
* ORIGIN TIME 0143 UTC APR 20 2015
* COORDINATES 23.9 NORTH 122.3 EAST
* DEPTH 1 KM / 0 MILES
* LOCATION SOUTHWESTERN RYUKYU ISLANDS JAPAN
EVALUATION
———-
* AN EARTHQUAKE WITH A PRELIMINARY MAGNITUDE OF 6.6 OCCURRED IN
THE SOUTHWESTERN RYUKYU ISLANDS, JAPAN AT 0143 UTC ON MONDAY
APRIL 20 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.
