There were strange crack/rolling sounds from alternating sides of the building during the quake, which felt like a gentle swirling than anything else. The quake took place hundreds of miles away. Per Wikipedia:
The Ritz-Carlton/JW Marriott hotel building, a part of the LA Live development in Los Angeles, California, is the first building in Los Angeles that uses an advanced steel plate shear wall system to resist the lateral loads of strong earthquakes and winds.
20 minutes later they came on the loudspeaker to say they were investigating any possibile structural damage to the building.
I just took some photos of the steel beam wall setups and have posted them below — according to the bartender here, this building is built to withstand a 12.0 magnitude earthquake. I feel much safer now.