UPDATE: Tsunami Waves Smaller Than Expected
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by Dave Smith
***Updated at 11:45 p.m.***
Although the first surges to hit Hawaii from the Canadian tsunami were smaller than expected, a tsunami warning continued to remain in effect across the state.
Measurements of the first surges to hit the islands varied from seven inches in Hanalei on Kauai to nearly two feet in Kahului, Maui.
In Hilo, the wave that arrived at 10:34 p.m. measured just over eight inches in height. That was the earliest wave to hit the islands, according to the six gauge readings contained in a report issued at 11:06 p.m. by the Pacific Tsunami Warning Center.
State Civil Defense previously said the first effects of the tremor to arrive in Hawaii were expected at Kauai at around 10:28 p.m., with waves hitting Hilo about 30 minutes later.
According to the report from the tsunami warning center, the wave hit Hanalei at 10:43 p.m., at Haleiwa on Oahu and Kahalui at 10:44 and at Waianae on Oahu’s leeward coast at 10:55 p.m.
Civil Defense officials were warning Hawaii residents to remain on alert as subsequent waves are often larger than the first one.
Hawaii has been under a statewide tsunami warning tonight since 7:09 p.m. as a result of a major earthquake that struck off the coast of Canada.
Tsunami warning sirens sounded across most of Hawaii and people in inundation zones were urged to evacuate immediately.
On the Big Island, tsunami warning sirens sounded repeatedly in Kona but were delayed in Hilo. The reason for the delay was not immediately known.
There was also some confusion created by a 6:30 p.m. bulletin from Hawaii County Civil Defense – that wasn’t emailed out until 8:30 p.m. – that said a tsunami warning was not in effect.
That report said while a tsunami wasn’t generated, Hawaii could experience “small non-destructive sea level changes” as well as strong currents that could last several hours.
The magnitude 7.7 earthquake that generated the waves struck at 5:04 Hawaii time. The earthquake’s epicenter was in a seismically active area in the Queen Charlotte Islands off the coast of British Columbia.
The tremor was initially measured at magnitude 7.1 but was later upgraded to a magnitude 7.7. It was followed by several aftershocks, including one several minutes later with a magnitude of 5.8.
The initial quake struck at a depth of 8.7 miles.
By about 9 p.m. Hawaii time The Associated Press was reporting that officials in North America downgraded a tsunami warning to an advisory for southern Alaska and British Columbia. They also issued an advisory for areas of northern California and southern Oregon.