In reality, all Civil Engineering work involve earth and its features. In Geology, they identify the origin of the earth, materials, and natural forces that effect earth on a daily basis. However, Civil Engineering relies on Geology on some important information that Engineers use to build such as, materials used, forces on the materials and Natural disasters.
In high school, you may have learned about the basic rock cycle. There are three different main rocks in earth such as, Igneous Rocks, Sedimentary Rocks and Metamorphic Rocks. They are all related to each other where magma cools to become an Igneous Rock then weathers to become Sedimentary Rock then by heat and pressure the rock becomes Metamorphic Rock with the cycle continuing.
In Civil Engineering, we are not interested in all these rocks shown, but we are more interested in Sedimentary Rocks. Most of the materials used in Construction are Sedimentary Rocks such as, Sand, gravel, silts and clay that come from sediments. For example, Limestone, a type of sediment, used to manufacture Portland Cement which is widely used in construction to glue rocks together. Especially Concrete which contains a mix of Sediments like limestone, sand, decomposed granite, and gravel that has been the main materiel used in many structures.
Plate tectonics mostly talks about how the plates move over time in geology. There are three major types of the plate tectonics which are Convergence boundary, Divergence boundary and Transform. Simple explanation for each is that Convergence plates move into each other, Divergence plates move away from each other and Transform plates move sideways. This three types of forces are used in Civil Engineering on a rock with a smaller scale than dealing with plates. We have three main forces in the mechanics of solids such as, tension, compression and shear. Tension comes from the idea of divergent plates, Compression comes from Convergence plates and Shear is from the transform plates.
In Geology, they study natural disasters such as, earthquakes and volcanoes and how they happen. However, In Civil Engineering they take this information to build structures that can resist huge amount of forces. That is why it’s expensive now a days to buy a house because Civil Engineers include more materiel and foundation to resist this natural disasters in the future. Not including earthquake resistance on a building and earthquake happens will just increase the casualties by a building falling.