I remember seeing an “aftershock” being shown on the Tonight Show once. Carson was very cool and calmed the audience immediately. He remarked later in the show about how the shock had traveled across the studio. First the audience got restless and noisy, then the cameras shook and finally he felt it. That was just how viewers witnessed it.
In other words, the live audience felt it first. It would not have suprised me if Carson commented on it afterwards.