The epicenter of an earthquake is located in a sandy desert region. seismic waves move outward from the epicenter. a rocky region is located a few hundred miles from the desert. the particles of matter are more closely packed in rock than they are in sand. which statement correctly describes the change in seismic waves as they move from sand to rock? a. the waves change from transverse to longitudinal. b. the waves change from longitudinal to transverse. c. the waves speed up. d. the waves slow down. e. the wave speed is unchanged.