HR: 09:40h
AN: T21B-07    [PDF]
TI: Deformation near the ends of Normal Fault Scarps
AU: * Kaven, J O
EM: ole@soest.hawaii.edu
AF: Department of Geology and Geophyiscs, University of Hawaii, 1680 East-West Road, Honolulu, HI 96822
AU: Martel, S J
EM: smartel@hawaii.edu
AF: Department of Geology and Geophyiscs, University of Hawaii, 1680 East-West Road, Honolulu, HI 96822
AB: Surface deformation along scarps of active normal faults on Kilauea volcano, Hawaii, reflects how the faults grow. We have mapped deformation near the east end of one east-striking fault that dips to the north, and the pattern resembles that along the east end of a previously-mapped fault that dips to the south. The scarps are breached monoclines with gentle monoclinal flexure extending past the end of the fault scarp trace. The monoclines demonstrate that the faults are growing from depth up towards the surface rather than from the surface down. Fractures on the monoclines form an echelon pattern. Monocline fractures strike east-southeast near the end of the fault that dips south; they strike east-northeast near the end of the fault that dips north. Belts of fissures characteristically form on both the uplifted footwall and the hanging wall, with a belt of buckles forming between the fault scarp and the hangingwall fissures. Fissures on the footwall have apertures about three times larger than those on the hangingwall. The belts of fissures and buckles are roughly parallel to the fault scarp away from the fault scarp ends, but these belts converge towards the end of the scarp trace. Away from the scarp end, fissures on the footwall generally strike roughly subparallel to the fault. Near the scarp trace end, the fissures form a pronounced echelon pattern. They strike east-southeast near the end of the fault that dips south, and they strike east-northeast near the end of the fault that dips north. The footwall fissures thus mirror the pattern of the fractures on the monocline. The pattern of fractures and fissures vary systematically with position relative to the fault tip. Three-dimensional boundary element analyses show that the fracture and fissure patterns are consistent with the along strike propagation of a normal fault as it grows towards the surface.
DE: 3210 Modeling
DE: 5104 Fracture and flow
DE: 8010 Fractures and faults
DE: 8020 Mechanics
SC: Tectonophysics [T]
MN: 2003 Fall Meeting