Animation of recent quakes around Hawaii Island April 21 to May 13, 2018. Animation courtesy of the Pacific Tsunami Warning Center.

Epicenter of the 4.6M quake at 11:53 p.m. Saturday, May 12, 2018.

Seismic waveform of the 4.6M quake at 11:53 p.m. Saturday, May 12, 2018.

TSUNAMI INFORMATION STATEMENT NUMBER 1
NWS PACIFIC TSUNAMI WARNING CENTER EWA BEACH HI
1157 PM HST SAT MAY 12 2018

TO – EMERGENCY MANAGEMENT IN THE STATE OF HAWAII

SUBJECT – LOCAL TSUNAMI INFORMATION STATEMENT

THIS STATEMENT IS FOR INFORMATION ONLY. NO ACTION REQUIRED.

AN EARTHQUAKE HAS OCCURRED WITH THESE PRELIMINARY PARAMETERS

ORIGIN TIME – 1154 PM HST 12 MAY 2018
COORDINATES – 19.4 NORTH 154.9 WEST
LOCATION – OFFSHORE OF THE KALAPANA REGION OF KILAUEA VOLCANO
MAGNITUDE – 4.3

EVALUATION

NO TSUNAMI IS EXPECTED. REPEAT. NO TSUNAMI IS EXPECTED.
HOWEVER…SOME AREAS MAY HAVE EXPERIENCED SHAKING.

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

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.