A new video from the U.S. Geological Survey offers an amplified look at how one of downtown Anchorage's landmark structures weathered the strong 7.1 earthquake that rattled Southcentral Alaska in January.
The video, posted on YouTube last week, depicts computer-generated movements of the Atwood Building at West Seventh Avenue and F Street -- magnified 300 times for study purposes -- during the Iniskin earthquake in the early hours of Sunday, Jan. 24.
No injuries were reported during the quake, but a Kenai neighborhood was temporarily evacuated due to fires fed by broken natural gas lines that destroyed several homes. Staff at the National Tsunami Warning Center in Palmer called the quake, centered about 160 miles southwest of Anchorage, the largest of its kind ever recorded in the Cook Inlet region.
Mehmet Celebi, a California-based USGS civil research engineer involved in making the video, said the idea of studying the Atwood's movement was suggested by members of the geological service's Anchorage office.
"What we are trying to do is to show the actual motions that a building such as that can have, which is translational -- north, south, east, west -- and then torsional, which is very strong in (the) Atwood," Celebi said. "And you can see that in the video."
Although the motion in the video is magnified, Celebi said how long the Atwood moves in the clip is unchanged from the day of the quake.
"You would have a hard time to see it by the naked eye, if you were standing outside the building," Celebi said. "The duration is something like 200, 300 seconds, and that is something that we are finding with the new set of modern instruments -- we can see how the motion elongates."
Celebi said he's also examining the movements of two other Anchorage buildings during the quake, including the Anchorage Hilton and the Frontier Building at 36th Avenue and A Street in Midtown. He said none of the three were damaged or threatened during the temblor.
"They all performed very well; there was no danger from the Iniskin earthquake," Celebi said. "Of course, like anything, they shook."