Recently I've taken an exceptionally unwise interest in the beliefs on conspiracy theorists, in particular flat earthers. Flat earthism has been trending heavily lately and indeed is undergoing some sort of revival. Of course, such beliefs run afoul of all scientific disciplines, including geology and geography.
This made me remember of the use of seismic waves to map the core of the earth and also the detection of earthquakes from remote parts of the globe. These, or course, rely on the true globular nature of the Earth.
Question: Are there particularly accessible or convincing accounts of such large scale detectable geologic phenomenon that implicitly rely on the globular geometry of the Earth?
Google would probably suffice but I'm not sure I have the correct terminology. [My background is in mathematics, in case that would be helpful.]
Edit: Let me clarify my request by asking for resources on global seismology which could be effectively presented to someone at college freshman level of education.