Editing Epicenter (section)

==Surface damage==
Before the instrumental period of earthquake observation, the epicenter was thought to be the location where the greatest damage occurred,<ref>{{cite book|title=The Geology of Earthquakes|first1=R. S.|last1=Yeats|first2=K. E.|last2=Sieh|authorlink2=Kerry Sieh|first3=C. R.|last3=Allen |authorlink3=Clarence Allen (geologist)|year=1997|isbn=978-0-19-507827-5|publisher=[[Oxford University Press]]|page=64}}</ref> but the subsurface [[Fault (geology)|fault]] rupture may be long and spread surface damage across the entire rupture zone. As an example, in the magnitude 7.9 [[2002 Denali earthquake|Denali earthquake of 2002]] in [[Alaska]], the epicenter was at the western end of the rupture, but the greatest damage was about {{cvt|330|km|||}} away at the eastern end.<ref>{{cite web|url=http://pubs.usgs.gov/fs/2003/fs014-03/|title=Rupture in South-Central Alaska – The Denali Fault Earthquake of 2002|publisher=United States Geological Survey|first=Gary|last=Fuis|author2=Wald, Lisa|access-date=2008-04-20}}</ref> Focal depths of earthquakes occurring in continental crust mostly range from {{convert|2|to|20|km|sp=us}}.<ref name="JordanGrotzinger2012">{{Cite book|title=The essential Earth|last1=Jordan|first1=Thomas H.|date=2012|publisher=W. H. Freeman|last2=Grotzinger|first2=John P.|isbn=9781429255240|edition=2nd|location=New York|page=429|oclc=798410008}}</ref> Continental earthquakes below {{cvt|20|km|||}} are rare whereas in [[subduction]] zone earthquakes can originate at depths deeper than {{cvt|600|km|||}}.<ref name="JordanGrotzinger2012"/>