Answer
They studies the earth processes and they also draw up safe building plans.
Explanation.
Geology is the science study part which pursues the understanding of how the earth is formed and the processes which change over time.Such processes are floods, land slides volcanic eruption e.t.c.
This study is carried out by geologist. These are professionals who have studied the various processes of the earth formation. They also draw up safe building plans.This is after they have investigated a certain area and verify it is safe for building. And once the building is built it cant be affected by any natural calamity such as land slide.