Elastography, tribo-elastography and passive-elastography: Elastography, sometimes referred as seismology of the human body, is an imaging modality recently implemented on medical ultrasound systems. Shear wave elatography measures shear waves within soft tissues and gives a tomography reconstruction of the shear elasticity. This elasticity map is useful for early cancer detection. A general overview of this field is given in the first part of the presentation. In a second part, elastography is used in a friction experiment. Indeed, elastography is an original tool for measuring elastic field inside soft solids and it provides a direct observation of friction, ruptures and waves in various regimes including slow slip and super-shear rupture. The third and last part is devoted to the application of a noise correlation technique in the field of elastography. The idea, as in seismology, is to take advantage of shear waves naturally present in the human body due to muscles activities to construct a shear elasticity map of the liver and the thyroid. It is thus a passive elastography approach since no shear wave sources are used.