The earthquake struck at 6:58 a.m. Sunday at a depth of about 6.0 miles, according to the U.S. Geological Survey (USGS). State seismologist Mike West tells the Anchorage Daily News, “This is a very significant event that will take us some time to understand.”
The Alaska Earthquake Center said the earthquake spawned a “vigorous aftershock sequence” that included a nearby 6.0 earthquake at 1:15 p.m. – the second largest earthquake ever recorded in the region. The last time a powerful earthquake hit the North Slope was in 1995, and it was a magnitude 5.2 West said.
Thirty minutes of ground motion data from seismic stations across Alaska. The red star is the epicenter, and the dots are stations. The animation includes two aftershocks, a M4.9 at 7:14 am and a M4.7 at 07:18. Q7Wy0ikGRj
— AK Earthquake Center (@AKearthquake) August 12, 2018
West explained the jump from a 5.2 to Sunday’s 6.4 is significant because earthquakes rapidly grow in strength as magnitude rises. A magnitude 6.4 earthquake is 15.8 times bigger and 63.1 times stronger than a 5.2 earthquake, according to the US Geological Survey.
“That’s why at 6.4 this changes how we think about the region,” West says “It’s a little early to say how, but it’s safe to say this earthquake will cause a re-evaluation of the seismic potential of that area.”
North Slope oil and gas leases
This latest earthquake is a significant event, and it will have an impact on the Trump administration’s decision to open the Arctic National Wildlife Refuge (ANWR) to oil and gas leasing, possibly as early as next year.
In July, the Washington Post reported the Interior Department had commissioned an expedited environmental review of the impact of leasing part of the Arctic National Wildlife Refuge for oil and gas drilling.
A $1.7 million contract with Colorado-based Environmental Management and Planning Solutions, set up by the liberal think tank Center for American Progress, was put into place, showing how quickly the White House was able to move ahead with its plans on getting drilling started as quick as possible.
The firm is given three months to complete a scoping report, which will set the terms of how federal officials will gauge the impact of energy development in the refuge. This will also include public comments and seismic reports.
“Seismic exploration generates acoustic waves that are picked up by sensors as the waves bounce off subsurface formations,” noted the Bureau of Land Management in a proposed action plan. “From this information, images can be created that show subsurface topography and formations including those areas of potential hydrocarbons.”
The earthquake has led to a more detailed examination of the event, and this should hold up and further actions on getting the North Slope opened for oil and gas leasing. There is a lot to do, and whatever comes of the Earthquake Center’s study will have an impact on future petroleum assets in the region.
The work to analyze the temblor has already begun, said West on Sunday. “We’ll understand a whole lot more about this earthquake as the days unfold, (exactly) how deep it was, the fault on which it occurred, its orientation, how long a rupture it was,” he said.
