A local expert said Alaska lies in an area prone to powerful earthquakes, and the 7.0-magnitude quake that struck the Anchorage area Friday afternoon could have strong aftershocks.
“A 7.0 earthquake is a damaging earthquake. It was a good shake,” said John E. Ebel, a senior research scientist at the Weston Observatory at Boston College, which has been recording earthquakes since the 1930s.
The epicenter of the earthquake appears to have been about 8 miles from Anchorage, in the area of the Prince William Sound, but the shaking was probably felt throughout much of Alaska and even in parts of Western Canada, Ebel said.
The shaking is usually strongest in areas with soft soil, which covers much of Alaska, Ebel said.
Alaska has more earthquakes than any other state, largely due to the fact that the southeastern part of the state lies on a subduction zone, a geographic area in which one tectonic plate slides underneath another. In this case, the Pacific Plate is pushing northwest and sliding underneath the North American Plate, Ebel said.
The 1964 Alaska earthquake, one of the largest earthquakes ever recorded, was a 9.2-magnitude quake, Ebel said.
The plate movement has the capacity to shake the earth and cause significant damage. Alaskans should expect aftershocks with a magnitude of between 5.0 and 6.0, Ebel said. It’s unlikely that any aftershocks will be as strong as the original quake, but it is possible, he said.
Officials had issued a tsunami warning shortly after the earthquake, fearing that vertical movement of the ocean floor could result in massive waves hitting shore, but the warning was later rescinded. Localized tsunami-like waves called seiches are possible, however, especially if the earthquake or its aftershocks trigger landslides into bodies of water, Ebel said.
New England can experience similar earthquakes, but far less often, as there is no nearby plate interaction. The last earthquake of a similar magnitude felt in the Northeast was a 7.5-magnitude earthquake that originated near Quebec City in 1663. The shaking damaged a few chimneys in Roxbury, Ebel said.