Wave speed = fλ
=(5 x 10^14)(4 x 10^-7)
=2 x 10^8
Where f is the frequency and λ is the wavelength
It doesn’t, a new tooth underneath your old one starts to push the right old one out, then the tooth comes loose and the tooth underneath continues growing.
Hope my answer helps!
I am not sure if this is the answer you are looking for but a earthquake occurs when the plates shift.
Hope this helped.