Claire Thomson
On the morning of Monday 11 October, the United States Geological Survey (USGS) reported a 6.9 magnitude earthquake off the coast of the Alaskan Peninsula.
The epicentre was around 71 miles east of the city of Chignik, which has approximately 100 inhabitants, at a supposed 43 miles deep.
The tremor was confirmed by the Alaska Earthquake Centre as an aftershock of the 8.2 earthquake, which hit the same region on July 28 and was the strongest earthquake in the United States, since the western Aleutian Islands were struck by an 8.7 magnitude earthquake in 1965. Aftershocks can continue for several months after the initial earthquake.
According to Express, more than 200 people living in Alaska reported the quake to the USGS. Whilst other people, more than 400 miles away from the epicentre, admitted to feeling the tremors with pictures on the wall shaking and beds trembling.
Surrounding Areas
Four smaller earthquakes were also recorded in the surrounding area, with magnitudes ranging between 2.7 and 3.3 on the Richter Scale. However, people generally only feel the shakes of those larger than about 3.0.
No tsunami warning or alert was issued by the US Tsunami Warning System, nor have any immediate injuries, damage or fatalities been reported. Tsunamis tend to occur when the magnitude exceeds 7.0, therefore, there was an unlikely chance of high levels of damage to the mainland. The initial earthquake in July triggered a tsunami warning in Hawaii, with waves expected to potentially reach as far as Australia.
The earthquake follows two strong tremors that hit off the coast of Big Island, Hawaii on Sunday 10 October. Both struck in the same area about 20 minutes apart, registering at magnitudes of 6.1 and 6.2, respectively. Once again, no fatalities or injuries were reported, and the Hawaii Department of Transportation declared there was no damage at airport runways, commercial harbours or highway bridges. However, the USGS believed that due to the strong seismic waves, there may have been very slight damage to buildings.
It is unlikely these two occurrences are strongly related, although it is possible for earthquakes to trigger other earthquakes in faraway regions due to a process known as dynamic stress triggering.
As a result of the so-called ‘Pacific Ring of Fire’, where seismic activity is particularly high due to crustal movements and volcanic activity, earthquakes are common in the Alaskan and Hawaiian areas. Around 90% of the world’s earthquakes occur in this region because of the overlapping and rubbing of tectonic plates.
Featured image courtesy of drhorstdonat from Pixabay. No changes or alterations were made to this image. Image license found here.
Claire Thomson
Aspiring Sports Journalist and Modern Languages Student (French/German) at University of Glasgow