Receiver functions are a commonly used seismic method in geophysics to better understand the Earth's interior structure. They are used to study the properties of the Earth's crust and upper mantle by analyzing the seismic waves that are recorded by seismometers. Receiver functions are obtained by analyzing the time delays and amplitudes of seismic waves that arrive at a seismometer from earthquakes at different depths within the Earth. By analyzing these data, researchers can infer details about the composition, thickness, and structure of the Earth's layers. Receiver functions are particularly useful for studying the Moho, which is the boundary between the Earth's crust and mantle, as well as other discontinuities within the Earth's interior.