<P> It was initially measured as a M 8.2 event, but later downgraded by the United States Geological Survey . The earthquake was felt throughout most of southern Alaska, including the major cities of Anchorage and Fairbanks, and parts of neighboring British Columbia . </P> <P> The earthquake prompted tsunami warnings and advisories for Alaska, British Columbia, the U.S. West Coast, and Hawaii . Residents in low - lying areas along the Gulf of Alaska and in British Columbia were evacuated to shelters and higher ground . The Pacific Tsunami Warning Center later cancelled most of the alerts within four hours of the earthquake, due to the apparent lack of tsunami . The highest recorded waves after the event measured at under 8.3 inches (210 mm) above tide level on Kodiak Island . </P> <P> According to the United States Geological Survey, the earthquake occurred 175 miles (282 km) southeast of Kodiak, Alaska at 12: 31 AM local time (AKST). Witnesses to the earthquake itself reported that it was very long in duration, feeling like a "slow roller," but it was not a violent earthquake despite its magnitude . This was corroborated by witnesses in Anchorage . There was no immediate damage reported . The earthquake woke people in Anchorage, 350 miles (560 km) from the epicenter, and was felt as far as Fairbanks to the northeast and British Columbia to the southeast . The earthquake's S - waves arrived in Anchorage within one minute, and reached Fairbanks within three minutes . </P> <P> The earthquake was a strike - slip event that occurred within the Pacific Plate . The epicenter was to the south of the Aleutian Trench, where the Pacific Plate subducts beneath the North American Plate . The region has produced twelve large earthquakes since 1900, including several megathrust earthquakes . </P>

How much damage did the alaska earthquake cause 2018