According to United States Geological Survey (USGS) data, more than 70 smaller tremors have rocked the Gulf of Alaska in the hours since yesterday’s quake, which was the joint seventh-largest earthquake ever recorded in the region.
The first major aftershocks came just 15 minutes after the 7.9-quake struck at 12.31am local time (9.31am GMT) on Tuesday, with the largest measuring 5.6 on the moment magnitude scale.
Most of the tremors that followed were recorded in the same localised area but are unlikely to have been felt by humans because of the area’s distance to any populated areas.
The vast majority of the tremors that followed measured between 2.5 and 4.5 on the Richter scale.
Yesterday’s earthquake sparked panic across the US after tsunami warnings were issued from Alaska to the southern tip of the US west coast.
Fleeing motorists clogged motorways and many took refuge in schools and shelters. Despite fears the earthquake would impact the entire US west coast, tsunami warnings and watches were gradually downgraded and at around 1.15pm GMT, people in Kodiak were given the all-clear.
Alaska’s coastal residents were urged to head inland to higher ground when the quake struck 157 miles (256km) south-east of Chiniak, Alaska.
People on Kodiak Island, one of the closest populated areas to the epicentre, were urged to stay away from the coast after the quake struck just 175 miles away.
The quake, initially measured at 8.2 on the Richter Scale, has since been downgraded to a magnitude of 7.9 by the US Geological Survey (USGS).
People were alerted to the danger by text messages and those in affected areas have been urged to seek high ground.
The text received by thousands of Alaskans this morning read: “Tsunami danger on the coast. Go to high ground or move inland. Listen to local news.-NWS.”
An announcer on KMXT public radio interrupted the regular broadcast to tell listeners: “This is a tsunami warning. this is not a drill. Please get out to higher ground.
“If you are on the flats, get up on one of the hills … Just go high.”