Editing Megathrust earthquake (section)

{{short description|Type of earthquake at convergent plate boundaries}}
{{Earthquakes}}

'''Megathrust earthquakes''' occur at [[convergent boundary|convergent plate boundaries]], where one [[tectonic plate]] is forced underneath another. The earthquakes are caused by slip along the [[thrust fault]] that forms the contact between the two plates. These [[interplate earthquake]]s are the planet's most powerful, with [[Moment magnitude scale|moment magnitudes]] (''M<sub>w</sub>'') that can exceed 9.0.<ref name="meier-etal-2017">{{cite journal |last1=Meier |first1=M.-A. |last2=Ampuero |first2=J. P. |last3=Heaton |first3=T. H. |title=The hidden simplicity of subduction megathrust earthquakes |journal=Science |date=22 September 2017 |volume=357 |issue=6357 |pages=1277–1281 |doi=10.1126/science.aan5643|pmid=28935803 |bibcode=2017Sci...357.1277M |s2cid=206660652 |url=https://resolver.caltech.edu/CaltechAUTHORS:20170925-075055125 }}</ref><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}}</ref> Since 1900, all [[earthquake]]s of magnitude 9.0 or greater have been megathrust earthquakes.<ref>{{Citation |first1= Arch C. |last1= Johnston |first2= Stephen |last2= Halchuk |date= June–July 1993 |title= The seismicity data base for the Global Seismic Hazard Assessment Program |journal= Annali di Geofisica |volume= 36 |issue= 3–4 |pages= 133–151 |url= http://www.annalsofgeophysics.eu/index.php/annals/article/download/4260/4329}}, pp. 140, 142 ''et seq''.</ref>

The thrust faults responsible for megathrust earthquakes often lie at the bottom of [[oceanic trench]]es; in such cases, the earthquakes can abruptly displace the sea floor over a large area. As a result, megathrust earthquakes often generate [[tsunami]]s that are considerably more destructive than the earthquakes themselves. [[Teletsunami]]s can cross ocean basins to devastate areas far from the original earthquake.