Editing Geography of Japan (section)

===Earthquakes and tsunami===
[[File:SH-60B helicopter flies over Sendai.jpg|thumb|The aftermath of the [[2011 Tōhoku earthquake and tsunami]]]]
{{see also|List of earthquakes in Japan}}
Japan is substantially prone to earthquakes, tsunamis, and volcanoes because of its location along the Pacific Ring of Fire.<ref>{{cite web |url=http://www.livescience.com/30226-japan-tectonics-explosive-geology-ring-of-fire-110314.html |title=Japan's Explosive Geology Explained |publisher=Live Science |last=Israel |first=Brett |date=March 14, 2011 |access-date=June 17, 2016 |archive-date=August 5, 2019 |archive-url=https://web.archive.org/web/20190805085127/https://www.livescience.com/30226-japan-tectonics-explosive-geology-ring-of-fire-110314.html |url-status=live }}</ref> It has the [[List of countries by natural disaster risk|15th highest natural disaster risk]] as measured in the 2013 World Risk Index.<ref name="2013 World Risk Report">[http://www.worldriskreport.com/uploads/media/WorldRiskReport_2013_online_01.pdf 2013 World Risk Report] {{webarchive |url=https://web.archive.org/web/20140816173655/http://www.worldriskreport.com/uploads/media/WorldRiskReport_2013_online_01.pdf |date=August 16, 2014 }}</ref>

As many as 1,500 earthquakes are recorded yearly, and magnitudes of 4 to 6 are common.<ref name=loc/> Minor tremors occur almost daily in one part of the country or another, causing slight shaking of buildings.<ref name=loc/> [[Undersea earthquake]]s also expose the Japanese coastline to danger from {{nihongo|[[tsunami]]s|津波}}.<ref name=loc/>

Destructive earthquakes, often resulting in tsunamis, occur several times each century.<ref name="volcanoes-japan" /> The [[1923 Great Kantō earthquake|1923 Tokyo earthquake]] killed over 140,000 people.<ref>{{cite web |last=James |first=C.D. |title=The 1923 Tokyo Earthquake and Fire |url=http://nisee.berkeley.edu/kanto/tokyo1923.pdf |publisher=University of California Berkeley |access-date=January 16, 2011 |year=2002 |url-status=dead |archive-url=https://web.archive.org/web/20070316050633/http://nisee.berkeley.edu/kanto/tokyo1923.pdf |archive-date=March 16, 2007}}</ref> More recent major quakes are the 1995 [[Great Hanshin earthquake]] and the [[2011 Tōhoku earthquake and tsunami|2011 Tōhoku earthquake]], a 9.1-magnitude<ref name="USGS9.1">{{cite web |url=https://earthquake.usgs.gov/earthquakes/eventpage/official20110311054624120_30#executive |title=M 9.1 – near the east coast of Honshu, Japan |publisher=Earthquake.usgs.gov |date=July 11, 2016 |access-date=August 29, 2017 |archive-date=April 7, 2011 |archive-url=https://web.archive.org/web/20110407005101/http://earthquake.usgs.gov/earthquakes/eqinthenews/2011/usc0001xgp/#executive |url-status=live }}</ref> quake that hit Japan on March 11, 2011. It triggered a large tsunami and the [[Fukushima Daiichi nuclear disaster]], one of the worst disasters in the history of nuclear power.<ref name="nytimes-tsunami">{{cite news |last=Fackler |first=Martin; Drew, Kevin |title=Devastation as Tsunami Crashes Into Japan |url=https://www.nytimes.com/2011/03/12/world/asia/12japan.html?ref=world |access-date=March 11, 2011 |work=The New York Times |date=March 11, 2011 |archive-date=July 28, 2018 |archive-url=https://web.archive.org/web/20180728101451/https://www.nytimes.com/2011/03/12/world/asia/12japan.html?ref=world |url-status=live }}</ref>

The 2011 Tōhoku earthquake was the largest ever recorded in Japan and is the world's fourth largest earthquake to strike since 1900, according to the U.S. Geological Service. It struck offshore about {{convert|371|km|mi}} northeast of Tokyo and {{convert|130|km|mi}} east of the city of [[Sendai]] and created a massive tsunami that devastated Japan's northeastern coastal areas. At least 100 aftershocks registering a magnitude of 6.0 or higher have followed the main shock. At least 15,000 people died as a result.

Researchers found the source of great thrust earthquakes and associated tsunamis in the [[Greater Tokyo Area]] at the [[Izu-Ogasawara Trench]].<ref name="phys1"/> There is a 'trench-trench triple junction' of the oceanic [[Philippine Sea Plate]] that underthrusts a continental plate and is being subducted by the [[Pacific Plate]].<ref name="phys1">{{cite web |author=Simon Fraser University |website=Phys.org |title=New source for earthquakes and tsunamis in the Greater Tokyo Region identified |url=https://phys.org/news/2021-09-source-earthquakes-tsunamis-greater-tokyo.html |access-date=September 12, 2021 |url-status=live |archive-url=https://web.archive.org/web/20210904134332/https://phys.org/news/2021-09-source-earthquakes-tsunamis-greater-tokyo.html |archive-date=September 4, 2021}}</ref>

Reclaimed land and human-made islands are particularly susceptible to [[Soil liquefaction|liquefaction]] during an earthquake. As a result, there are specific earthquake resistance standards and ground reform work that apply to all construction in these areas. In an area that was possibly reclaimed in the past, old maps and land condition drawings are checked, and drilling is carried out to determine the strength of the ground. However, this can be very costly, so for a private residential block of land, a Swedish weight sounding test is more common.<ref name="reclaimed-land"/>

Japan has become a world leader in research on the causes and prediction of earthquakes.<ref name=loc/> The development of advanced technology has permitted the construction of [[skyscraper]]s even in earthquake-prone areas.<ref name=loc/> Extensive civil defense efforts focus on training in protection against earthquakes, in particular against accompanying fire, which represents the greatest danger.<ref name=loc/>