The process of getting a PhD in earth science is fairly straightforward and requires that you be admitted to a suitable doctoral program in that discipline. To qualify for a PhD in earth science, you obtain a bachelor's degree in geology, physical science or earth science. At the completion of your bachelor's degree, you can enter either a program a master's degree program, as a foundation for the PhD, or you can apply to a doctoral program directly. Once you enter a PhD program, you will select a narrow aspect of earth science to study and complete an appropriate research project to complete the degree program.
First, you will need to apply for admittance into a bachelor's degree program in earth science or a related field. You do not necessarily have to obtain your bachelor's degree in earth science, though your chances of admission to a graduate program will be better if you already have a foundation in a similar discipline. A bachelor's degree in geology, physics, or even chemistry is acceptable, however.
The bachelor's degree program will consist of about 80 units of coursework in general education courses and about 40 units in coursework that is directly related to the major. Once you have been accepted to a bachelor's degree program, you must earn the best grades that you can in all of your courses. The higher your grade point average (GPA), the better chance you have of being admitted to a program that will grant you a PhD in earth science.
If you choose to earn a master's degree before beginning your doctoral program, it may be more efficient to choose a university that offers a master's program that moves directly into a program leading to a PhD in earth science. Such a program will require an extensive time commitment, of up to seven years, and will often require that you work as a graduate or a teaching assistant in the school's Earth Science department. The master's degree will require approximately 30 units of coursework focused on a particular area of earth science. For dual degree programs, once you complete the master's degree segment, you will transition immediately into the doctoral program if your performance has been satisfactory.
You may also apply directly to doctoral programs immediately following the completion of your bachelor's degree. Be aware that admittance to PhD programs is highly competitive, and students with a master's degree in the discipline may have an advantage over those with only a bachelor's degree. Requirements for the PhD vary by university but generally include the completion of a dissertation or research project.