The transition from craton to rift in south eastern Africa: Preliminary surface wave tomography from the MOZambique Rift Tomography (MOZART) project
Abstract
We present preliminary results from the MOZART (Mozambique Rift Tomography) experiment in the context of the transition from the old and cold lithosphere associated with the Kalahari Craton, to the continental lithosphere associated with the southern tip of the East African Rift System (EARS) in Mozambique. The initial stage of surface wave data recorded on the network of 30 broadband seismic stations deployed in 2011 are incorporated into an earlier continental scale tomographic model of Africa (Fishwick, 2010). These data provide a significant increase in potential resolution of upper mantle velocities, in a region where there has previously been little knowledge of the detailed lithospheric structure. Furthermore they allow a better comparison with the velocities observed beneath the Kaapvaal Craton where data from the dense network of seismometers deployed in the earlier Southern Africa Seismic Experiment (SASE) have already been included in the regional tomography. From the new tomographic models we investigate the lateral gradients in seismic velocity at upper mantle depths of 75-250km in order to place better constraints on the thermal and/or chemical transitions from the craton to the rift. In order to test the reliability of these estimates of the velocity gradient we compare different parameterisations and regularisations, but also investigate to what degree the addition of new data to the tomographic model alters the estimated velocities. The regional tomographic model produced will provide a useful new reference model for more detailed inter-station and array tomography when project MOZART is completed in mid-2013.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFM.T23C2682F
- Keywords:
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- 8124 TECTONOPHYSICS / Earth's interior: composition and state;
- 8125 TECTONOPHYSICS / Evolution of the Earth;
- 8180 TECTONOPHYSICS / Tomography