Origins of oblique-slip faulting during caldera subsidence
2013 (English)In: Journal of Geophysical Research, ISSN 0148-0227, E-ISSN 2156-2202, Vol. 118, no 4, 1778-1794 p.Article in journal (Refereed) Published
Although conventionally described as purely dip-slip, faults at caldera volcanoes may have a strike-slip displacement component. Examples occur in the calderas of Olympus Mons (Mars), Miyakejima (Japan) and Dolomieu (La Reunion). To investigate this phenomenon, we ran numerical and analog simulations of caldera subsidence caused by magma reservoir deflation. The numerical models constrain mechanical causes of oblique-slip faulting from the three-dimensional stress field in the initial elastic phase of subsidence. The analog experiments directly characterize the development of oblique-slip faulting, especially in the later, non-elastic phases of subsidence. The combined results of both approaches can account for the orientation, mode and location of oblique-slip faulting at natural calderas. Kinematically, oblique-slip faulting originates to resolve: (1) horizontal components of displacement that are directed radially toward the caldera centre; and (2) horizontal translation arising from off-centered or ‘asymmetric’ subsidence. We informally call these two origins the “camera iris” and “sliding trapdoor” effects, respectively. Our findings emphasize the fundamentally three-dimensional nature of deformation during caldera subsidence. They hence provide an improved basis for analyzing structural, geodetic and geophysical data from calderas, as well as analogous systems, such as mines and producing hydrocarbon reservoirs.
Place, publisher, year, edition, pages
2013. Vol. 118, no 4, 1778-1794 p.
collapse calderas, subsidence, oblique-slip faults, ring faults, wrinkle ridges, strike-slip component
Earth and Related Environmental Sciences Geology
Research subject Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics
IdentifiersURN: urn:nbn:se:uu:diva-188487DOI: 10.1002/jgrb.50057ISI: 000319926600028OAI: oai:DiVA.org:uu-188487DiVA: diva2:577903