terremoti

Modern seismometers include 3 elements to determine the simultaneous movement in 3 directions: up-down, north-south,and east-west. Each direction of movement gives information about the earthquake. This animation shows both the movement of the three basic waves (P, S, and surface) and the effect of the waves on a building. The three seismograms produced by a modern seismograph station show that the P wave is more visible on the vertical component and the S wave amplitude is larger on the horizontal components.[…]