HR: 1340h
AN: S33A-1050    [Abstracts]
TI: Shear Wave Velocity Structure Of The Bushveld Complex
AU: Dirks, P
EM: paul.dirks@wits.ac.za
AF: Paul Dirks, School of Geosciences Private Bag 3, Johannesburg, 2050, South Africa
AU: Kgaswane, E
EM: eeikgasw@geosc.psu.edu
AF: Council for Geoscience, 280 Pretoria Street Silverton, Private Bag X112, Pretoria, 0001, South Africa
AU: Kgaswane, E
EM: eeikgasw@geosc.psu.edu
AF: Penn State University, Department of Geosciences Deike Building, State College, PA 16802, United States
AU: * Nyblade, A
EM: andy@geosc.psu.edu
AF: Penn State University, Department of Geosciences Deike Building, State College, PA 16802, United States
AB: The Bushveld Complex is a prominent ultramafic intrusion located in the northern part of the Kaapvaal Craton. It is unknown if there is connectivity and continuity of the ultramafic units at depth across the complex and especially beneath the central zone. The object of this study is to model the structure of the complex to depths of around 10 km by first measuring Rayleigh wave group velocities from 1 to 10 second periods, and then inverting them to obtain a model of the variation of shear wave speeds with depth. The group velocity measurements are being made mostly using earthquakes (ML greater than 2.5) from the local gold mines that were recorded by the SASE (South African Seismic Experiment) broadband network (1997 to 1999) and on AfricaArray stations. Data from regional earthquakes surrounding the Bushveld Complex is also being used to improve azimuthal coverage. The velocity models should shed some light on the stratification and tectonic setting of the ultramafic layering and also reveal whether there is connectivity and continuity at depth for areas without surface exposure.
DE: 7218 Lithosphere (1236)
DE: 7230 Seismicity and tectonics (1207, 1217, 1240, 1242)
DE: 7255 Surface waves and free oscillations
SC: Seismology [S]
MN: 2007 Fall Meeting