UPDATE: 7 p.m., Tsunami Advisory Canceled for Hawai‘i After 7.5 Alaska Earthquake, Hazard has Passed

PC: Pacific Tsunami Warning Center.

Update: 7:01 p.m. Oct. 19, 2020

The tsunami advisory is ended for the State of Hawaiʻi, effective at 6:58 p.m HST.

The Pacific Tsunami Warning Center issued an update saying, “Tsunami wave heights across the State of Hawaiʻi are now below advisory levels and are continuing to diminish. Measurements recorded for Kahului and Hilo are now below advisory levels. Based on all available data, the Pacific Tsunami Warning Center is now canceling the tsunami advisory.”

The PTWC notes that small sea level changes and strong or unusual currents may persist for several additional hours in some coastal areas and appropriate caution should be exercised by boaters and swimmers.

This will be the final message issued for this event, unless additional data are received.

The advisory was issued at 4:46 p.m. after advisory level sea level changes were observed at Hilo and Kahului.  Earlier in the day, the PTWC had advised that there was no threat to Hawaiʻi, but later issued the advisory based on sea level changes observed and the potential hazard to swimmers and boaters.

The observations were made after a 7.5 (preliminary magnitude 7.4) earthquake reported at 10:55 a.m. on Monday, Oct. 19, 2020 south of Alaska.

Update: 5:55 p.m. Oct. 19, 2020

Earlier today, the PTWC had advised that there was no threat to Hawaiʻi, but later issued an advisory based on sea level changes observed and the potential hazard to swimmers and boaters.

The agency maintains that based on all available data, “a major tsunami is not expected to strike the state of Hawaiʻi; however, sea level changes have been recorded at Hilo and Kahului just above advisory level that could be a hazard to swimmers and boaters as well as to persons near the shore at beaches and in harbors and marinas.  The threat may continue for several hours after the initial wave arrival.”

The Pacific Tsunami Warning Center issued an update at 4:46 p.m., and another at 5:55 p.m. on Monday, Oct. 19, 2020, saying a tsunami advisory remains in effect for the state of Hawaiʻi.  This comes after a 7.5 (preliminary magnitude 7.4) earthquake reported at 10:55 a.m. on Monday, Oct. 19, 2020 south of Alaska.

The first elevated waves were expected shortly before 3:30 p.m. on Monday, Oct. 19, 2020.

The PTWC notes that further messages will be issued hourly or sooner as conditions warrant until the threat to Hawaiʻi has passed.

MEASUREMENTS OR REPORTS OF TSUNAMI WAVE ACTIVITY

GAUGE LOCATION LAT LON TIME AMPL PER
——————- —– —— —– ————— —–
HANALEI HI 22.2N 159.5W 0304Z 0.26M / 0.8FT 18MIN
NAWILIWILI HI 22.0N 159.4W 0142Z 0.09M / 0.3FT 12MIN
KAWAIHAE HAWAII 20.0N 155.8W 0205Z 0.05M / 0.2FT 12MIN
MOKUOLOE OAHU 21.4N 157.8W 0214Z 0.02M / 0.1FT 08MIN
HILO HI 19.7N 155.1W 0211Z 0.30M / 1.0FT 16MIN
HALEIWA HI 21.6N 158.1W 0147Z 0.19M / 0.6FT 10MIN
KAHULUI MAUI 20.9N 156.5W 0200Z 0.38M / 1.2FT 20MIN

Update: 4:46 p.m. Oct. 19, 2020

The Pacific Tsunami Warning Center issued an update at 4:46 p.m. on Monday, Oct. 19, 2020, saying a tsunami advisory has been issued for the state of Hawaiʻi, effective at 4:38 p.m.  This comes after a 7.5 (preliminary magnitude 7.4) earthquake reported at 10:55 a.m. on Monday, Oct. 19, 2020 south of Alaska.

The agency maintains that based on all available data, “a major tsunami is not expected to strike the state of Hawaiʻi; however, sea level changes have been recorded at Hilo and Kahului just above advisory level that could be a hazard to swimmers and boaters as well as to persons near the shore at beaches and in harbors and marinas.  The threat may continue for several hours after the initial wave arrival.”

The estimated time of arrival of the initial wave was at 3:27 p.m. HST on Monday, Oct. 19, 2020.

Further messages will be issued hourly or sooner as conditions warrant until the threat to Hawaiʻi has passed.

Earlier today, the PTWC had advised that there was no threat to Hawaiʻi, but later issued an advisory based on sea level changes observed and the potential hazard to swimmers and boaters.

Previous Post: 

There is no tsunami threat to Hawaiʻi after a 7.5 (preliminary magnitude 7.4) earthquake reported at 10:55 a.m. on Monday, Oct. 19, 2020 south of Alaska.

The Pacific Tsunami Warning Center says a tsunami threat exists for parts of the Pacific located closer to the earthquake; however, based on all available data, there is no tsunami threat to Hawaiʻi.

The notification will be the only statement issued for the event, unless additional data are received.

The USGS reports that the quake was located:

• 91.5 km (56.8 mi) NW of Sand Point, Alaska, United States
• 925.7 km (575.2 mi) NE of Anchorage, Alaska, United States
• 946.1 km (587.9 mi) NE of Eagle River, Alaska, United States
• 960.5 km (596.8 mi) NNE of Knik-Fairview, Alaska, United States
• 1586.2 km (985.6 mi) ENE of Juneau, Alaska, United States

Alaska earthquake. PC: USGS.