A total of 18 earthquakes have struck Alaska today alone, the biggest being a 4.3 earthquake about 68km from Kobuk. The previous day a huge magnitude-5.2 earthquake struck at 9.27pm UTC time. The earthquake struck some 66km from Kobuk, at a depth of 19.7km. Just a few hours later, at 11.33pm UTC time, a magnitude-4.5 earthquake struck 107km from Cold Bay.
According to the US Geological Survey (USGS), aftershocks are expected to continue.
The USGS aftershock forecast reported: “More earthquakes than usual (called aftershocks) will continue to occur near the mainshock.
“When there are more earthquakes, the chance of a large earthquake is greater which means that the chance of damage is greater.
“The USGS advises everyone to be aware of the possibility of aftershocks, especially when in or around vulnerable structures such as unreinforced masonry buildings.
“This earthquake could be part of a sequence. An earthquake sequence may have larger and potentially damaging earthquakes in the future, so remember to: Drop, Cover, and Hold on.”
According to the USGS detailed aftershock report, the chance of an earthquake of magnitude three or higher is 67 percent in the next week.
The report adds: “It is most likely that as few as 0 or as many as 18 such earthquakes may occur in the case that the sequence is re-invigorated by a larger aftershock.”
The chance of a magnitude five or higher has now dropped to three percent for the next week.
Alaska forms part of the ‘Ring of Fire’, a massive horseshoe-shaped ring encircling the Pacific basin made up of a string of volcanoes and seismic activity.
About 90 percent of all earthquakes occur along the Ring of Fire, which is dotted with 75 percent of all the active volcanoes on earth.
A string of 452 volcanoes stretches from the southern tip of South America, up the coast of the Americas, across the Bering Strait, down through Japan and into New Zealand.
In total, the ring forms a 25,000 mile arc from the boundary of the Pacific Plate, to the Cocos and Nazca Plates that line the edge of the Pacific Ocean.