Example of positive polarity on the vertical component, i.e. the first ground motion is up.

Example of negative polarity on the vertical component, i.e. the first ground motion is down.

Fault plane solution – 1. Fault plane Aux. plane From An introduction to seismology, earthquakes and earth structure by Stein & Wysession

Fault plane solution – 2. From An introduction to seismology, earthquakes and earth structure by Stein & Wysession earth’s surface

From An introduction to seismology, earthquakes and earth structure by Stein & Wysession Fault plane solution – 3.

From An introduction to seismology, earthquakes and earth structure by Stein & Wysession Fault plane solution – 4.

From An introduction to seismology, earthquakes and earth structure by Stein & Wysession Fault plane solution – 5.