Mechanical waves travelling through Earth's surface or interior.
They are the main study subject of Reflection Seismology in Subsurface Exploration.
It can be a Surface wave propagating Earth's surface or a Body wave A Primary wave (p-wave) in Reflection Seismology of Subsurface Exploration and s-wave) propagating through Earth's interior.
See also
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Natural Science / Geoscience / Subsurface Exploration / Reflection Seismology
[ Earth's Structure ][ Geology ] [ Seismic Waves ]
[ Surface wave ][ Body wave ][ p-wave ][ s-wave ]