seismic waves are a seismic wave that travels along the earth surface.
seismic waves are a seismic wave that travels along the earth surface.
a seismic wave that travels along the earth surface?
seismic waves
by the 1960s, earth science had developed to the point where a comprehensive theory of the causation of seismic events had come together in the now well-established theory of plate tectonics.









































section::::types of seismic wave.









































seismic waves are elastic waves that propagate in solid or fluid materials. they can be divided into "body waves" that travel through the interior of the materials; "surface waves" that travel along surfaces or interfaces between materials; and "normal modes", a form of standing wave.









































section::::types of seismic wave.:body waves.
seismology
seismic anomalies are identified by mapping variations in wave speed as seismic waves travel through earth. a hot mantle plume is predicted to have lower seismic wave speeds compared with similar material at a lower temperature. mantle material containing a trace of partial melt (e.g., as a result of it having a lower melting point), or being richer in fe, also has a lower seismic wave speed and those effects are stronger than temperature. thus, although unusually low wave speeds have been taken to indicate anomalously hot mantle beneath "hot spots", this interpretation is ambiguous. the most commonly cited seismic wave-speed images that are used to look for variations in regions where plumes have been proposed come from seismic tomography. this method involves using a network of seismometers to construct three-dimensional images of the variation in seismic wave speed throughout the mantle.
mantle plume