Seismic waves that spread through the Earth’s deep interior: BANG! or QUAKE! three stations at different distances
from the sourc nces e ista 90º t d en er iff 60º d at s n o ti ta s e e r 30º h T CRUST (very thin)
Seismic source CORE
MANTLE 90º 60º
30º 90º 60º
30º 90º 60º
30º
The wavefront position is shown after it has been traveling for several minutes. It continues to travel throughout the Earth's interior, bouncing off the core, and bouncing off the Earth's surface.
1.5 million seismic events since 1960, located by the International Seismological Centre on the basis of data from about 17,000 stations (up to ~ 6000 in any one year)
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