Editing Seismology (section)

==History==
Scholarly interest in earthquakes can be traced back to antiquity. Early speculations on the natural causes of earthquakes were included in the writings of [[Thales]] of Miletus ({{circa|585 BCE}}), [[Anaximenes of Miletus]] ({{circa|550 BCE}}), [[Aristotle]] ({{circa|340 BCE}}), and [[Zhang Heng]] (132 CE).

In 132 CE, Zhang Heng of China's [[Han dynasty]] designed the first known [[seismoscope]].<ref name=needham>{{cite book|last=Needham|first=Joseph|title=Science and Civilization in China, Volume 3: Mathematics and the Sciences of the Heavens and the Earth|place=Cambridge|publisher=Cambridge University Press|year=1959|pages=626–635|bibcode=1959scc3.book.....N}}</ref><ref name="DeweyByerly">{{cite journal|last1=Dewey|first1=James|last2=Byerly|first2=Perry|date=February 1969|title=The early history of seismometry (to 1900)|url=https://pubs.geoscienceworld.org/ssa/bssa/article/59/1/183/101553/The-early-history-of-seismometry-to-1900|journal=Bulletin of the Seismological Society of America|volume=59|issue=1|pages=183&ndash;227}}</ref><ref>{{cite journal|last1=Agnew|first1=Duncan Carr|title=History of seismology|journal=International Handbook of Earthquake and Engineering Seismology|series=International Geophysics|volume=81A|pages=3&ndash;11|date=2002|doi=10.1016/S0074-6142(02)80203-0|bibcode=2002InGeo..81....3A |isbn=9780124406520}}</ref>

In the 17th century, [[Athanasius Kircher]] argued that earthquakes were caused by the movement of fire within a system of channels inside the Earth. [[Martin Lister]] (1638–1712) and [[Nicolas Lemery]] (1645–1715) proposed that earthquakes were caused by chemical explosions within the Earth.<ref name=Lisbon>{{cite book|first1=Agustín|last1=Udías|last2=Arroyo|first2=Alfonso López|contribution=The Lisbon earthquake of 1755 in Spanish contemporary authors|editor-last1=Mendes-Victor|editor-first1=Luiz A.|editor-last2=Oliveira|editor-first2=Carlos Sousa|editor-last3=Azevedo|editor-first3=João|editor-last4=Ribeiro|editor-first4=Antonio|title=The 1755 Lisbon earthquake: revisited|page=14|date=2008|publisher=Springer|isbn=9781402086090}}</ref>

The [[1755 Lisbon earthquake|Lisbon earthquake of 1755]], coinciding with the general flowering of science in [[Europe]], set in motion intensified scientific attempts to understand the behaviour and causation of earthquakes.  The earliest responses include work by [[John Bevis]] (1757) and [[John Michell]] (1761). Michell determined that earthquakes originate within the Earth and were waves of movement caused by "shifting masses of rock miles below the surface".<ref>{{cite book|last1=Member of the Royal Academy of Berlin|title=The History and Philosophy of Earthquakes Accompanied by John Michell's 'conjectures Concerning the Cause, and Observations upon the Ph'nomena of Earthquakes'|date=2012|publisher=Cambridge Univ Pr|isbn=9781108059909}}</ref>

In response to a series of earthquakes near [[Comrie, Perth and Kinross|Comrie]] in [[Scotland]] in 1839, a committee was formed in the [[United Kingdom of Great Britain and Ireland|United Kingdom]] in order to produce better detection methods for earthquakes. The outcome of this was the production of one of the first modern [[seismometer]]s by [[James David Forbes]], first presented in a report by [[David Milne-Home]] in 1842.<ref name=JamesForbes /> This seismometer was an inverted pendulum, which recorded the measurements of seismic activity through the use of a pencil placed on paper above the pendulum. The designs provided did not prove effective, according to Milne's reports.<ref name=JamesForbes>{{cite web|url=https://www.researchgate.net/publication/261697732|title=The Study of Earthquakes in the Hundred Years Following Lisbon Earthquake of 1755|last=Oldroyd|first=David|date=2007|website=Researchgate|publisher=Earth sciences history: journal of the History of the Earth Sciences Society|access-date=4 October 2022}}</ref>

From 1857, [[Robert Mallet]] laid the foundation of modern instrumental seismology and carried out seismological experiments using explosives. He is also responsible for coining the word "seismology."<ref>{{Cite journal|last=Society|first=The Royal|date=2005-01-22|title=Robert Mallet and the 'Great Neapolitan earthquake' of 1857|journal=Notes and Records|language=en|volume=59|issue=1|pages=45–64|doi=10.1098/rsnr.2004.0076|s2cid=71003016|issn=0035-9149}}</ref> He is widely considered to be the "Father of Seismology".

In 1889 [[Ernst von Rebeur-Paschwitz]] recorded the first teleseismic earthquake signal (an earthquake in Japan recorded at Pottsdam Germany).<ref>{{Cite web|url=http://bib.gfz-potsdam.de/pub/digi/seismograms.pdf|title=Historical Seismograms from the Potsdam Station|date=1989|publisher=Academy of Sciences of German Democratic Republic, Central Institute for the Physics of the Earth.|access-date=April 7, 2020}}</ref>

In 1897, [[Emil Wiechert]]'s theoretical calculations led him to conclude that the [[Structure of the Earth|Earth's interior]] consists of a mantle of silicates, surrounding a core of iron.<ref>{{cite journal|last1=Barckhausen|first1=Udo|last2=Rudloff|first2=Alexander|title=Earthquake on a stamp: Emil Wiechert honored|journal=Eos, Transactions American Geophysical Union|date=14 February 2012|volume=93|issue=7|pages=67|doi=10.1029/2012eo070002|bibcode=2012EOSTr..93...67B|doi-access=free}}</ref>

In 1906 [[Richard Dixon Oldham]] identified the separate arrival of [[P wave]]s, S waves and surface waves on seismograms and found the first clear evidence that the Earth has a central core.<ref>{{cite encyclopedia|title=Oldham, Richard Dixon|encyclopedia=Complete Dictionary of Scientific Biography|volume=10|publisher=[[Charles Scribner's Sons]]|year=2008|page=203}}</ref>

In 1909, [[Andrija Mohorovičić]], one of the founders of modern seismology,<ref name="Penn state">{{cite web|url=https://www.e-education.psu.edu/earth520/node/1777|title=Andrya (Andrija) Mohorovicic|publisher=[[Pennsylvania State University|Penn State]]|access-date=30 January 2021|archive-date=26 June 2013|archive-url=https://archive.today/20130626180816/https://www.e-education.psu.edu/earth520/node/1777|url-status=live}}</ref><ref name="Encyclopedia.com">{{cite web|url=https://www.encyclopedia.com/people/history/historians-miscellaneous-biographies/andrija-mohorovicic|title=Mohorovičić, Andrija|publisher=[[Encyclopedia.com]]|access-date=30 January 2021|archive-date=1 February 2021|archive-url=https://archive.today/20210201205826/https://www.encyclopedia.com/people/history/historians-miscellaneous-biographies/andrija-mohorovicic|url-status=live}}</ref><ref name="ssn">{{cite web|url=http://www.seismosoc.org/Publications/SRL/SRL_78/srl_78-6_hs.html|title=Andrija Mohorovičić (1857–1936) – On the occasion of the 150th anniversary of his birth|publisher=Seismological Society of America|access-date=30 January 2021|archive-date=1 February 2021|archive-url=https://archive.today/20210201210211/http://www.seismosoc.org/Publications/SRL/SRL_78/srl_78-6_hs.html|url-status=live}}</ref> discovered and defined the [[Mohorovičić discontinuity]].<ref name=McLeish>{{cite book|title=Geological science|author=Andrew McLeish|page=122|url=https://books.google.com/books?id=rhkgwEvrVe8C&pg=PA122|isbn=978-0-17-448221-5|date=1992|edition=2nd|publisher=[[Thomas Nelson & Sons]]}}</ref> Usually referred to as the "Moho discontinuity" or the "[[Mohorovičić discontinuity|Moho]]," it is the boundary between the [[Earth]]'s [[Crust (geology)|crust]] and the [[Mantle (geology)|mantle]]. It is defined by the distinct change in velocity of seismological waves as they pass through changing densities of rock.<ref>{{Citation|last1=Rudnick|first1=R. L.|title=3.01 – Composition of the Continental Crust|date=2003-01-01|url=http://www.sciencedirect.com/science/article/pii/B0080437516030164|journal=Treatise on Geochemistry|editor-last=Holland|editor-first=Heinrich D.|publisher=Pergamon|doi=10.1016/b0-08-043751-6/03016-4|isbn=978-0-08-043751-4|access-date=2019-11-21|last2=Gao|first2=S.|volume=3|page=659|bibcode=2003TrGeo...3....1R|editor2-last=Turekian|editor2-first=Karl K.}}</ref>

In 1910, after studying the April [[1906 San Francisco earthquake]], [[Harry Fielding Reid]] put forward the "[[Elastic-rebound theory|elastic rebound theory]]" which remains the foundation for modern tectonic studies.  The development of this theory depended on the considerable progress of earlier independent streams of work on the behavior of elastic materials and in mathematics.<ref>{{Cite web|url=https://earthquake.usgs.gov/regional/nca/1906/18april/reid.php|title=Reid's Elastic Rebound Theory|website=1906 Earthquake|publisher=United States Geological Survey|access-date=6 April 2018}}</ref>

An early scientific study of [[aftershock]]s from a destructive earthquake came after the January [[1920 Xalapa earthquake]]. An {{cvt|80|kg}} Wiechert seismograph was brought to the Mexican city of Xalapa by rail after the earthquake. The instrument was deployed to record its aftershocks. Data from the seismograph would eventually determine that the mainshock was produced along a shallow crustal fault.<ref>{{cite journal|first1=G.|last1=Suárez|first2=D. A.|last2=Novelo-Casanova|title=A Pioneering Aftershock Study of the Destructive 4 January 1920 Jalapa, Mexico, Earthquake|journal=Seismological Research Letters|date=2018|volume=89|issue=5|pages=1894–1899|doi=10.1785/0220180150|bibcode=2018SeiRL..89.1894S|s2cid=134449441|url=https://www.researchgate.net/publication/326613511}}</ref>

In 1926, [[Harold Jeffreys]] was the first to claim, based on his study of earthquake waves, that below the mantle, the core of the Earth is liquid.<ref>{{Cite journal|last=Jeffreys|first=Harold|date=1926-06-01|title=On the Amplitudes of Bodily Seismic Waues.|journal=Geophysical Journal International|language=en|volume=1|pages=334–348|doi=10.1111/j.1365-246X.1926.tb05381.x|issn=1365-246X|bibcode=1926GeoJ....1..334J|doi-access=free}}</ref>

In 1937, [[Inge Lehmann]] determined that within Earth's liquid [[outer core]] there is a solid [[inner core]].<ref>{{Cite journal|last=Hjortenberg|first=Eric|date=December 2009|title=Inge Lehmann's work materials and seismological epistolary archive|url=http://www.annalsofgeophysics.eu/index.php/annals/article/viewFile/4625/4693|journal=Annals of Geophysics|volume=52|issue=6|doi=10.4401/ag-4625|doi-access=free}}</ref>

In 1950, [[Michael S. Longuet-Higgins]] elucidated the ocean processes responsible for the global background seismic [[microseism]].<ref name=LonguetHiggins>{{Citation|first=M. S.|last=Longuet-Higgins|author-link=Michael S. Longuet-Higgins|title=A theory of the origin of microseisms|journal=[[Philosophical Transactions of the Royal Society A]]|volume=243|pages=1–35|year=1950|doi=10.1098/rsta.1950.0012|issue=857|bibcode=1950RSPTA.243....1L|s2cid=31828394}}</ref>

By the 1960s, Earth science had developed to the point where a comprehensive theory of the causation of seismic events and geodetic motions had come together in the now well-established theory of [[plate tectonics]].<ref>{{Cite web|title=History of plate tectonics|url=http://scecinfo.usc.edu/education/k12/learn/plate2.htm|access-date=2024-02-20|website=scecinfo.usc.edu}}</ref>