How can the arrival and progress of an earthquake be recognized on a seismogram?

a. by wavy lines of characteristic shapes

b. by gaps of characteristic shapes in a line

c. by a steadily rising line

d. by three intersecting circles

Hello!

The answer to your question is A.

By wavy lines of characteristic shapes

~Hope this Helps!~

i think that d. wind is the answer.   i missed the question when i answered a. currents.

the correct answer, according to e2020, is the second choice there is an occluded front in region a and a cold front in region b.