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dc.contributor.advisorJonsson, Sigurjon
dc.contributor.authorLiu, Yuan-Kai
dc.date.accessioned2018-05-07T13:58:37Z
dc.date.available2018-05-07T13:58:37Z
dc.date.issued2018-05
dc.identifier.citationLiu, Y.-K. (2018). Ground Deformation Related to Caldera Collapse and Ring-Fault Activity. KAUST Research Repository. https://doi.org/10.25781/KAUST-2L8U9
dc.identifier.doi10.25781/KAUST-2L8U9
dc.identifier.urihttp://hdl.handle.net/10754/627773
dc.description.abstractVolcanic subsidence, caused by partial emptying of magma in the subsurface reservoir has long been observed by spaceborne radar interferometry. Monitoring long-term crustal deformation at the most notable type of volcanic subsidence, caldera, gives us insights of the spatial and hazard-related information of subsurface reservoir. Several subsiding calderas, such as volcanoes on the Galapagos islands have shown a complex ground deformation pattern, which is often composed of a broad deflation signal affecting the entire edifice and a localized subsidence signal focused within the caldera floor. Although numerical or analytical models with multiple reservoirs are proposed as the interpretation, geologically and geophysically evidenced ring structures in the subsurface are often ignored. Therefore, it is still debatable how deep mechanisms relate to the observed deformation patterns near the surface. We aim to understand what kind of activities can lead to the complex deformation. Using two complementary approaches, we study the three-dimensional geometry and kinematics of deflation processes evolving from initial subsidence to later collapse of calderas. Firstly, the analog experiments analyzed by structure-from-motion photogrammetry (SfM) and particle image velocimetry (PIV) helps us to relate the surface deformation to the in-depth structures. Secondly, the numerical modeling using boundary element method (BEM) simulates the characteristic deformation patterns caused by a sill-like source and a ring-fault. Our results show that the volcano-wide broad deflation is primarily caused by the emptying of the deep magma reservoir, whereas the localized deformation on the caldera floor is related to ring-faulting at a shallower depth. The architecture of the ring-fault to a large extent determines the deformation localization on the surface. Since series evidence for ring-faulting at several volcanoes are provided, we highlight that it is vital to include ring-fault activity in numerical or analytical deformation source formulation. Ignoring the process of ring-faulting in models by using multiple point sources for various magma reservoirs will result in erroneous, thus meaningless estimates of depth and volume change of the magmatic reservoir(s).
dc.language.isoen
dc.subjectcaldera subsidence
dc.subjectoverlapping deformation
dc.subjectanlog models
dc.subjectboundary element modeling
dc.subjectring-faults
dc.subjectInterferometric synthetic aperture radar (SAR) (InSAR)
dc.titleGround Deformation Related to Caldera Collapse and Ring-Fault Activity
dc.typeThesis
dc.contributor.departmentPhysical Science and Engineering (PSE) Division
thesis.degree.grantorKing Abdullah University of Science and Technology
dc.contributor.committeememberSantamarina, Carlos
dc.contributor.committeememberThoroddsen, Sigurdur T
thesis.degree.disciplineEarth Science and Engineering
thesis.degree.nameMaster of Science
refterms.dateFOA2018-06-13T12:01:34Z


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