Thanks for the advice everyone! The tripod was situated between the sound and light boards, which was a carpeted floor with what felt like a wood base under it. It was inside an old theater. I've had minor vibration issues in the past, but this was so significant that the video isn't enjoyable. I'm not worried about attempting to correct in post, but I want to be better prepared for future events. Again, thank you all for the good suggestions. If anyone has further advice, all is welcome.