MEDIA RELEASE
The U.S. Geological Survey’s Hawaiian Volcano Observatory (HVO) recorded a magnitude-4.2 earthquake located off the northeast coast of O‘ahu on Friday, September 15, 2017, at 8:40 p.m. HST.
The earthquake was located about 33 km (20 mi) northeast of Kaneohe, O‘ahu, at a depth of 10 km (6.3 mi). A map showing the location of the earthquake is posted on HVO’s website at https://volcanoes.usgs.gov/hvo/earthquakes/
The USGS “Did you feel it?” website (https://earthquake.usgs.gov/dyfi/) received over 500 felt reports ranging from Kaua‘i to the Island of HawaiÊ»i. The maximum intensity of shaking reported was IV on the Mercalli Intensity Scale, indicating light shaking.
“The earthquake was likely due to bending of the oceanic plate from the weight of the island chain and poses no significant hazard,†said HVO Seismic Network Manager Brian Shiro.
According to the Pacific Tsunami Warning Center (PTWC) no tsunami was generated by the earthquake.
For more information on recent earthquakes in Hawai‘i and eruption updates, visit the Hawaiian Volcano Observatory website at https://volcanoes.usgs.gov/hvo/
TSUNAMI INFORMATION STATEMENT NUMBER 1 NWS PACIFIC TSUNAMI WARNING CENTER EWA BEACH HI 1020 PM HST FRI SEP 15 2017 TO - EMERGENCY MANAGEMENT IN THE STATE OF HAWAII SUBJECT - LOCAL TSUNAMI INFORMATION STATEMENT THIS STATEMENT IS FOR INFORMATION ONLY. NO ACTION REQUIRED. AN EARTHQUAKE OCCURRED THIS EVENING WITH THESE REVIEWED PARAMETERS FROM THE USGS - HAWAIIAN VOLCANO OBSERVATORY ORIGIN TIME - 0841 PM HST 15 SEP 2017 COORDINATES - 21.6 NORTH 157.5 WEST LOCATION - OFF THE WINDWARD COAST OF OAHU MAGNITUDE - 4.2 EVALUATION THIS EARTHQUAKE WAS FELT BY MANY ON OAHU. THERE WAS NO TSUNAMI THREAT FROM THIS EARTHQUAKE. 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.
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