Passive Seismic Experiment
The Passive Seismic Experiment studied the propagation of seismic waves through the Moon and provided a detailed look at the Moon's internal structure. The Passive Seismic Experiment produced several important scientific results:
Knowledge of Lunar Interior Structure: Moon has crust, mantle and core like earth. The lunar crust is rich in the mineral plagioclase and has an average crust thickness of 60-70 kilometers. The lunar mantle lies between the crust and the core and consists mostly of the minerals olivine and pyroxene. The core is composed mostly of iron and sulphur.
Distribution of Lunar Seismic Sources: The seismometer network recorded more than 1700 meteoroid impacts, with impact masses estimated to be between 0.5 and 5000 kilograms.
Attenuation of Seismic Waves: Meteoroid impacts cause heavy fracturing in the upper 20 kilometers of the lunar crust. These fractures in turn cause scattering of seismic waves. Below 20 kilometers, seismic wave scattering decreases due to the change in the chemical composition of moon.