Editing Convergent boundary (section)

== Earthquakes and tsunamis ==
{{See also|Earthquake}}
Earthquakes are common along convergent boundaries. A region of high earthquake activity, the [[Wadati–Benioff zone]], generally dips 45° and marks the subducting plate. Earthquakes will occur to a depth of {{cvt|670.|km}} along the Wadati-Benioff margin.{{citation needed|date=May 2023}}

Both compressional and extensional forces act along convergent boundaries. On the inner walls of trenches, compressional faulting or reverse faulting occurs due to the relative motion of the two plates. Reverse faulting scrapes off [[ocean sediment]] and leads to the formation of an accretionary wedge. Reverse faulting can lead to [[megathrust earthquake]]s. Tensional or normal faulting occurs on the outer wall of the trench, likely due to bending of the downgoing slab.<ref>{{Cite journal|date=1969-06-01|title=Seismology and the new global tectonics|journal=Tectonophysics|volume=7|issue=5–6|pages=527–541|doi=10.1016/0040-1951(69)90024-9|issn=0040-1951|last1=Oliver|first1=J.|last2=Sykes|first2=L.|last3=Isacks|first3=B.|bibcode=1969Tectp...7..527O}}</ref>

A megathrust earthquake can produce sudden vertical displacement of a large area of ocean floor. This in turn generates a [[tsunami]].<ref name="nrc-canada">{{cite web|title=Questions and Answers on Megathrust Earthquakes|url=https://earthquakescanada.nrcan.gc.ca/zones/cascadia/qa-en.php|publisher=Natural Resources Canada|access-date=23 September 2020|date=19 October 2018|archive-date=27 October 2020|archive-url=https://web.archive.org/web/20201027064104/https://earthquakescanada.nrcan.gc.ca/zones/cascadia/qa-en.php|url-status=live}}</ref>

Some of the deadliest natural disasters have occurred due to convergent boundary processes. The [[2004 Indian Ocean earthquake and tsunami]] was triggered by a megathrust earthquake along the convergent boundary of the Indian plate and Burma microplate and killed over 200,000 people. The 2011 [[2011 Japan Tsunami|tsunami off the coast of Japan]], which caused 16,000 deaths and did US$360 billion in damage, was caused by a magnitude 9 megathrust earthquake along the convergent boundary of the Eurasian plate and Pacific plate.