If a large earthquake were to occur at San Diego the earliest indication at another California locationo f the occurrence of that earthquake would be the arrival of the?

The earliest indication of a large earthquake occurring in San Diego at another California location would be the arrival of seismic P-waves (primary waves). These waves travel faster than S-waves (secondary waves) and are typically the first to be detected by seismic instruments. While P-waves can be felt as a slight shaking, they usually cause minimal damage compared to the subsequent S-waves.