Author Question: Why do most earthquakes occur along the circum-Pacific belt? What will be an ideal ... (Read 58 times)

serike · **on:** Jul 15, 2018

Why do most earthquakes occur along the circum-Pacific belt? What will be an ideal response?

Question 2

Describe the three categories of earthquakes based on focal depth and what causes them. What will be an ideal response?

rleezy04 · **Reply #1 on:** Jul 15, 2018

Answer to Question 1

Convergent plate boundaries line the Pacific basin, since the Pacific is shrinking and the Atlantic is
growing due to plate tectonics motions. As plates subduct, they create earthquakes along their distance.
The Pacific basin also has some transform faults along it, including the San Andreas in California.

Answer to Question 2

Shallow-focus earthquakes have focal depths of less than 70 km; intermediate-focus earthquakes have
focal depths between 70 and 300 km; and deep-focus earthquakes have focal depths of more than 300
km. Divergent and transform plate boundaries produce only shallow-focus quakes, and all
intermediate- and deep-focus quakes occur along convergent boundaries