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Earthquakes (and other earth movements) produce different types of seismic waves. These waves travel through rock, and provide an effective way to "see" events and structures deep in the Earth.

One of the earliest important discoveries was that the center of the Earth is liquid. Pressure waves pass through the core. Waves that shake side-to-side, requiring a rigid material, do not.

The process of mapping subsurface features is a specialty called seismography . Seismic waves produced by explosions have been used to map salt domes and other oil-bearing rocks, faults (cracks in deep rock), rock types, and long-buried giant meteor craters. For example, Chicxulub, the meteor that is believed to have killed the dinosaurs, was localized to Central America by analyzing ejecta in the cretaceous boundary, and then physically proven to exist using seismic maps from oil exploration.

Using seismic tomography with earthquake waves, the interior of the Earth has been completely mapped to a resolution of several hundred kilometers. This process has enabled scientists to identify convection cells, magma plumes and other large features of the inner Earth.

One of the first attempts of earthquakes scientific study occurred following the 1755 Lisbon earthquake.

1 Seismologists

• Gutenberg, Beno
• Kanamori, HirooHiroo Kanamori (born October 17, 1936) is an earthquake seismologist who has made fundamental contributions to understanding the physics of earthquakes and the tectonic processes that cause them. His most visible public contribution has been the moment ma
• Lehmann, IngeInge Lehmann ( May 13, 1888 February 21, 1993), Fellow of the Royal Society (London) 1969, was a Danish seismologist who, in 1936, argued that the Earth must not only have a molten interior, but a solid core at the center, which deflects P waves. She also
• Mercalli, GiuseppeGiuseppe Mercalli was an Italian volcanologist who developed the Mercalli Intensity Scale. He was born in 1850 in Milan and he died in 1914 in Naples. See also Richter_scale.
• Mohorovicic, AndrijaAndrija Mohorovicic ( January 23 1857 December 18, 1936) was a noted meteorologist and seismologist. Early years Born in the village Volosko, near Opatija, in Istria, Croatia, he obtained the elementary education there and continued study in the gymnasium
• Oldham, Richard DixonRichard Dixon Oldham ( July 31, 1858 July 15, 1936) was a British geologist who, in 1906, argued that the Earth must have a molten interior as S waves were not able to travel through liquids nor through the Earth's interior. See also: Lehmann, Inge, seism
• Richter, Charles FrancisCharles Francis Richter ( April 26, 1900 April 20, 1985), was an American seismologist, born in Hamilton, Ohio. He is most famous as the creator of the Richter Magnitude Scale, which quantifies the size of earthquakes. He first used the scale in 1935.