The Liberal Gun Club Forum

atxgunguy wrote: Fri Nov 30, 2018 2:34 pm Got a friend who was in Wasilla for an Iditarod meeting when the Tsunami warning went off. As Wasilla is apparently in the inundation zone, they were told to go to higher ground.

She's a dog musher from Wisconsin, I could only imagine the WTF moment she had.

Experts emphasized they are still studying the Anchorage temblor but said several factors made it less destructive than other major quakes.

For one thing, the quake was not centered directly under Anchorage. The epicenter was about 8½ miles away, said Jonathan Tytell, a geophysicist with the U.S. Geological Survey. That’s still fairly close, but doesn’t have the same effect as if it were directly under the city.

The quake was also fairly deep, 25 miles underneath the surface, which also resulted in less shaking at the surface, said Joann Stock, a geology and geophysics professor at Caltech. The magnitude 6.7 Northridge quake hit directly underneath the suburban San Fernando Valley and was much shallower — just 11 miles underground — than the Anchorage quake, so more of the shaking energy made it to the surface, causing more damage.

“Earthquakes are just complex,” said Heidi Tremayne, director of the Earthquake Engineering Research Institute. “Each has its own thumbprint.”Much of the structural damage seen in Anchorage was the result of liquefaction, which is when sediments and water are shaken together and act like quicksand.

Anchorage is a newer city, with fewer old buildings that are likely to collapse, Tremayne said. Building codes for newer construction are designed to allow buildings to easily withstand the shake intensity ranges seen in the Anchorage earthquake, she said.

The great 1964 Alaska quake — a magnitude 9.2 monster that battered the whole West Coast with shaking and tsunami — significantly damaged many buildings, so there are few of Anchorage’s oldest structures left, Tremayne said. That’s not the case in many other cities.The 1964 Alaska temblor, the second-largest earthquake in the modern record, produced 1,995 times more energy than Friday’s quake. It lasted 4½ minutes and, along with its tsunamis, killed more than 120 people. It was felt all the way to Seattle, where witnesses said they felt the landmark Space Needle swaying.

A later U.S. Geological Survey study found that an area of 185,000 square miles was disrupted. There were areas that dropped as much as eight feet and others rose 38 feet. Barnacles attached to rocks that used to be two feet underwater were suddenly in the open air. A section of downtown Anchorage sank. Underwater landslides in Alaska’s fjords caused tsunamis within minutes of the shaking. Three huge waves washed into Whittier from Prince William Sound within three minutes. Chenega, to the south, lost 23 people, one-third of its population. To the north In Valdez, 30 died as the harbor and docks collapsed. Eleven people were killed by a tsunami that hit Crescent City, Calif.