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.
What causes uneven skin tone? The main causes of uneven skin tone are hyperpigmentation, sun spots, hormones and discolouration due to acne scarring. An excess of melanin or pigment in the skin due to sun exposure creates freckles and eventually, isolated dark spots.