For a typical steel framed 30 ft by 30 ft office building bay, the fre-quency will be in the 5-8 Hz range. Frequency is a function of span (the longer the span, the lower the frequen-cy) and weight supported (the heavier the floor and the supported contents, the lower the frequency).
Anxiety doesn't appear to cause any dramatic changes to your skin color. You're not going to turn blue or purple. But some degree of skin color change is normal with anxiety and stress, especially under extreme anxiety like during a panic attack.
Pigmentation is color in your skin produced by melanin, a natural pigment that also determines eye and hair color. However, if too much melanin is produced in one area, the result is a brown patch on your skin ( brown spot or hyper-pigmentation.)