Branches of geology involve the study of the Earth's structure at a microscopic level. Physical characteristics of rocks are recorded, and in petrography there is a specific focus on the examination of microscopic details of rocks. Similar to scanning electron microscopes, electron microprobes can be used in petrology to observe the condition that allows rocks to form, which can inform the origin of these samples. In structural geology, petrographic microscopes allow the study of rock microstructures, to determine how geologic features such as tectonic plates affect the likelihood of earthquakes and groundwater movement.