Chapter 27, Problem 16TE

To determine

The cause of earthquakes in southern California

Answer to Problem 16TE

The movement of huge blocks of the earth’s crust, that is the Pacific and North American plates is the main reason for earthquakes in southern California.

Explanation of Solution

The last noticeable earthquake in the southern California of the San Andreas fault was in $1857$. Southern California faces several thousands of orders of earthquakes every year and most of them are not the noticeable ones as mentioned above.

The reason behind the rate of earthquakes in the southern Calfornia of the San Andreas fault is due to the big band from the southern end of the San Joaquin Valley to the eastern region of the Bernardino mountains. The rate of occurrence of earthquakes is nearly 1000 per year in this region.

So, the earthquakes in California are generated due to the movement of huge blocks of the earth’s crust. The Pacific plate is moving northwest, which scarps North America horizontally at a rate of about $2\text{ inches}$.

Conclusion:

Therefore, the movement of huge blocks of the earth’s crust, that is the Pacific and North American plates is the main reason for earthquakes in southern California.