You did not undeline 'appeared'; you underlined 'Stare...minute'. so that is what I examined and commented upon. Now you come back to me in disbelief. I agree that 'appeared' seems odd; without further context, I would use 'appear'.
A few months after being put on the market, the building was sold and painted hot pink with tangerine trim. The combination of colors gave the house a raw, jittery feeling. Stare at the facade for more than a minute, and the doors and windows appeared to tremble, as if suffering the effects of a powerful amphetamine.
Me, too - I misunderstood why you posted that. Yes, with further context I can see why the writer used past tense: the whole passage is a description of the past. The 'Stare' clause is uncommon there (since it does indeed mean 'If you stare...'), but it is still OK, I think.