Geologists have learned of the Earth's structure by studying the speed at which seismic waves generated by earthquakes travel through the layers, and have estimated the composition of these layers by comparing the seismic velocities to the velocities measured in rocks at the Earth's surface.
(Geologists; have learned; of the Earth's structure) Context(Geologists have learned,List([0, 23))):(Geologists; have learned of the Earth's structure by studying; the speed at which seismic waves generated by earthquakes travel through the layers) (the velocities; measured; in rocks; L:at the Earth's surface) (seismic waves; generated; by earthquakes) (seismic waves generated by earthquakes; travel; through the layers) (Geologists; have estimated; the composition of these layers; by comparing the seismic velocities to the velocities)
Geologists have learned,List([0, 23))
Geologists Geologists the velocities seismic waves seismic waves generated by earthquakes Geologists
have learned have learned of the Earth's structure by studying measured generated travel have estimated
of the Earth's structure
the speed at which seismic waves generated by earthquakes travel through the layers
in rocks L:at the Earth's surface
by earthquakes
through the layers
the composition of these layers by comparing the seismic velocities to the velocities