Editing Sunda Arc (section)

== Formation and geologic setting ==
Mid-oceanic ridge basalts [[Basalt|(MORB)]] form most of the oceanic basin south of Sunda, according to geodynamic studies.<ref name=":62">{{Cite journal|last=Hall|first=Robert|date=2002-04-01|title=Cenozoic geological and plate tectonic evolution of SE Asia and the SW Pacific: computer-based reconstructions, model and animations|url=http://www.sciencedirect.com/science/article/pii/S1367912001000694|journal=Journal of Asian Earth Sciences|series=Cenozoic geological and plate tectonic evolution of SE Asia and the SW Pacific: Computer-based reconstructions, model and animations (including CD-ROM)|language=en|volume=20|issue=4|pages=353–431|doi=10.1016/S1367-9120(01)00069-4|bibcode=2002JAESc..20..353H|issn=1367-9120|url-access=subscription}}</ref> These plates began to converge in the Early [[Miocene Era|Miocene]].<ref name=":62"/> The [[Indo-Australian Plate]] is subducting beneath the [[Eurasian Plate]] with a dip angle of 49–56 degrees.<ref>{{Cite journal|last1=Syracuse|first1=Ellen M.|last2=Abers|first2=Geoffrey A.|date=2006-05-23|title=Global compilation of variations in slab depth beneath arc volcanoes and implications: ARC VOLCANO SLAB DEPTH|journal=Geochemistry, Geophysics, Geosystems|language=en|volume=7|issue=5|pages=n/a|doi=10.1029/2005GC001045|s2cid=134426211 |doi-access=free}}</ref> The slab subducting under Java is continuous down to the lower mantle. However, the slab appears to beak apart under [[Sumatra|Sumatra Island]]''.''<ref>{{Cite journal|last1=Pesicek|first1=J. D.|last2=Thurber|first2=C. H.|last3=Widiyantoro|first3=S.|last4=Engdahl|first4=E. R.|last5=DeShon|first5=H. R.|date=2008|title=Complex slab subduction beneath northern Sumatra|journal=Geophysical Research Letters|language=en|volume=35|issue=20|pages=L20303|doi=10.1029/2008GL035262|bibcode=2008GeoRL..3520303P|s2cid=129435818 |issn=1944-8007|doi-access=free}}</ref><ref name=":52">{{Cite journal|last1=Widiyantoro|first1=S.|last2=van der Hilst|first2=R.|date=1996-03-15|title=Structure and Evolution of Lithospheric Slab Beneath the Sunda Arc, Indonesia|url=https://www.science.org/doi/10.1126/science.271.5255.1566|journal=Science|language=en|volume=271|issue=5255|pages=1566–1570|doi=10.1126/science.271.5255.1566|bibcode=1996Sci...271.1566W|s2cid=128483384|issn=0036-8075|url-access=subscription}}</ref> Earthquake depth records indicate that there is no deep seismic activity in [[Sumatra]], likely due to the age of the subducting complex''.''<ref>{{Cite journal|last1=Wortel|first1=M. J. R.|last2=Vlaar|first2=N. J.|date=1988|title=Subduction zone seismicity and the thermo-mechanical evolution of downgoing lithosphere|url=http://link.springer.com/10.1007/BF00874551|journal=Pure and Applied Geophysics|language=en|volume=128|issue=3–4|pages=625–659|doi=10.1007/BF00874551|bibcode=1988PApGe.128..625W|s2cid=55287111|issn=0033-4553|url-access=subscription}}</ref><ref name=":52" /><ref>{{Cite journal|last1=Kirby |first1=S.H |author-link=S.H |last2=Stein|first2=S.|author3-link=Okal|last3=Okal|first3=EA|author4-link=Rubie|last4=Rubie|first4=D.|date=1996|title=Deep earthquakes and metastable mantle phase transformations in subducting oceanic lithosphere|url=https://agupubs.onlinelibrary.wiley.com/doi/10.1029/96RG01050|journal=Rev. Geophys. Space Phys.|volume=34|doi=10.1029/96RG01050|url-access=subscription}}</ref> Two types of subductions have been identified along the Sunda Arc: 1) orthogonal subduction along Java and 2) [[oblique subduction]] on the Sumatra side. These subductions are separated by the [[Sunda Strait]].<ref>{{Cite journal|last1=Kopp|first1=Heidrun|last2=Flueh|first2=Ernst R.|last3=Klaeschen|first3=Dirk|last4=Bialas|first4=Jörg|last5=Reichert|first5=Christian|date=2001-11-01|title=Crustal structure of the central Sunda margin at the onset of oblique subduction|journal=Geophysical Journal International|language=en|volume=147|issue=2|pages=449–474|doi=10.1046/j.0956-540x.2001.01547.x|bibcode=2001GeoJI.147..449K|s2cid=130459678 |issn=0956-540X|doi-access=free}}</ref>