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.