The Richter scale is a base-10 logarithmic scale. What feature of an earthquake is multiplied by a factor of 10 for a unit increase on the Richter [RIK-tur] scale?

W) Total energy radiated by an earthquake

X) Fault rupture velocity

Y) Seismic [SIZE-mic] wave amplitude

Z) Seismic moment
Y) SEISMIC WAVE AMPLITUDE