Vibration sources are applied to a body or other object to image a region of interest. The mechanical vibrations introduced by the sources interfere in the region of interest to produce a crawling wave, which is detected by an ultrasound probe A relationship between crawling wave phase derivatives and local shear wave velocity is derived with phase derivatives estimated using either one-dimensional (1D) or two-dimensional (2D) autocorrelation-based techniques to image the region of interest.