Earthquake Lab:

The lag time for St. Louis is 21 secondsP

S

•Fault Scarps

•Steep mountain fronts

•Offset streams (Dogleg streams)

•Sag ponds and lakes

•Valleys in fault zones

•Changes in rock type

Offset fence

Point Reyes

Fault Scrap in the Mecca Hills, Southern California

Fault scarp

Fault Scrap Central California

scarp

Linear ridge

Offset stream

Linear valley

Spot the clues that would tell a geologist if she was walking in this area that a fault-line is here.

Color in rock types Tc,and Tnv

What do they tell you?

When did these fault-lines roughly last move?

Using Tnv, calculate the speed of movement since the middle of the eocene.

Tnv

TnvTnv

Qos

Loma Prieta

A. Seismicity (1969-89) before Loma Prieta

B. Loma Prieta earthquake and aftershocks

San Jose could be next!

Cross-section of Loma Prieta Earthquake

Intensities of 1906 San Francisco earthquake