That was the case with the Alaskan Peninsula earthquake, because it had a reported depth of 29 miles (46.3km). Most tsunamis are generated by earthquakes with magnitudes over 7.0, which this one was not, and that occur under or very near the ocean.Īgain, that does not apply to this particular earthquake because its epicenter was about 71 miles (114km) east of the village of Chignik, according to the US Geological Survey.įinally, if the earthquake occurs less than 62 miles (100km) beneath the Earth's surface then a tsunami is more likely. The main factors determining whether one is likely are the location, magnitude and depth of an earthquake. However, the US Tsunami Warning Center has said there is no threat of a tsunami. Why hasn't a tsunami warning been issued?Īn earthquake with a preliminary magnitude of 6.9 struck early Monday off the coast of Alaska. The earthquake comes just a day another with a magnitude of 6.2 struck south of the island of Hawaii on Sunday, but there was no tsunami warning afterward and no immediate reports of damage.

While Monday's tremor hit 71 miles east of Chignik, the July earthquake hit 56 miles southeast of the town of Perryville, meaning the quakes were around 38 miles apart. Monday's earthquake was felt by residents along the Alaska Peninsula and Kodiak Island but there was no tsunami threat, according to the U.S. The tremor was confirmed by the Alaska Earthquake Center as an aftershock of the 8.2 earthquake, which struck on July 28 and was the strongest felt in the US since an 8.7 quake ripped through the western Aleutian Islands in 1965.Īftershocks can continue over a period of weeks, months, or years, according to the US Geological Survey's Earthquake Hazards Program. The depth was reported at 29 miles (46.3 km) deep. The epicenter was about 71 miles (114 kilometers) east of the city of Chinik, the U.S. An earthquake with a preliminary magnitude of 6.9 struck early Monday off the coast of Alaska, two months after America's biggest earthquake in 50 years struck the same region.

Alaska quake