  The formation and dynamics of cavities in liquids leads to focusing of
kinetic energy and emission of longitudinal stress waves during the cavity
collapse. Here we report that cavitation in elastic solids may additionally
emit shear waves that could affect soft tissues in human bodies/brains. During
collapse of the cavity close to an air-solid boundary, the cavity moves away
from the boundary and forms a directed jet flow, which confines shear stresses
in a volume between the bubble and the free boundary. Elastographic and
high-speed imaging resolve this process and reveal the origin of a shear wave
in this region. Additionally, the gelatin surface deforms and a conical crack
evolves. We speculate that tissue fracture observed in medical therapy may be
linked to the non-spherical cavitation bubble collapse.
