The earthquake in Alaska that wakened residents of the south-central portion of that state in the early hours of Sunday morning has been upgraded back to a 7.1 magnitude (7.1M). Early reports by the U.S. Geological Survey put the strength of the earthquake at 7.1M, but then quickly downgraded it to 6.8M. The upgrade back to 7.1M comes amid reports of a home explosion and fire.
The quake hit at approximately 1:30 a.m. and was strong enough to cause tremors that lasted for about 30 seconds. The effects of the earthquake in Alaska were felt in the majority of the state’s most populated areas. While there have been no reports of serious injury or death, the earthquake in Alaska has resulted in a swath of destruction, including a home explosion. More than 30 homes were evacuated from a neighborhood in Kenai, a community on the Kenai Peninsula near the quake’s epicenter, when a gas leak was reported. A fire began in one home and as firefighters battled the flames, the house next door exploded, spreading the fire. Four homes in total were lost to the blaze. Residents are still waiting to get back into their homes as utility workers examine the area and establish temporary lines if necessary. The explosion and fire has left about 20 people staying in a temporary shelter at the local Armoury, with a Red Cross team assisting them as the investigation continues.
The Anchorage fire department continues to field numerous reports of water and gas line breaks with the full toll of damage yet to be tabulated. The earthquake in Alaska resulted in power outages in the Anchorage area, leaving at least 10,000 customers without electricity. Among the accounts were reports of road damage in some areas outside the city.
The epicenter off the earthquake in Alaska was located in the ocean floor off the coast, 52 miles east of Old Iliamna or about 162 miles south of Anchorage and 77.5 miles deep. It was followed by a series of some 30 aftershocks over the next two and a half hours with two of them measured at 4.7M and 4.3M. Products flew from store shelves, and the effects of the earthquake in Alaska were felt by seismologists as far away as Norway. Aftershocks continue throughout Sunday and may persist for weeks.
This Sunday’s earthquake in Alaska is classified as an intermediate-depth quake, one that may be felt at longer distances but is typically less destructive to the surface than one centered at a shallow-focus, or less than 45 miles deep. Experts do not expect that a tsunami will develop as a result of Sunday’s quake.
The area of southern Alaska is prone to frequent earthquake events related to tectonic plate activity, resulting from friction between the Pacific Plate and the North American Plate. The Pacific Plate subducts beneath the North American plate, and earthquakes result from sudden lurches that occur between the two. Sunday’s quake follows a 4.8 magnitude earthquake in Alaska that struck roughly the same region about a week ago on the evening of January 17. There were no reports of injuries or damage on that occasion.
The epicenter of Sunday’s earthquake in Alaska falls in a region that has seen more than 17 earthquakes of magnitude 6 or greater. The area is also just to the southeast of the location of the second largest earthquake ever recorded, the Great Alaska earthquake that occurred on March 27, 1964 and resulted in a tsunami, as well as the deaths of 131 people and extensive property damage.
[Map courtesy of the US Geological Survey (USGS) on 24 January 2016]