I ended up going to the office again today for about 5 hours. I took the photo above through my office window at sunset.
At one point in the afternoon, I was sitting at my desk, alone on the 20th floor, when I noticed the building was swaying. The blinds in my office were swinging back and forth a couple of inches, and I could hear things shifting and creaking. This stopped after a minute or two, and I made a note of the time -- 3:25 p.m. After returning home, I heard about the earthquake of 7.9 magnitude in Alaska, which news reports placed at "just after" 3:00 p.m. MST.