Rayleigh wave tomography in the Main Ethiopian Rift using ambient noise
Abstract
In this study, the structure of the crust and uppermost mantle beneath and surrounding the Main Ethiopian Rift (MER) has been investigated to better understand the origin and structural evolution of the rift. Data for the study comes from permanent and temporary broadband seismic stations deployed in Ethiopia during the past decade. Rayleigh wave group velocity maps have been constructed for 7-30 s periods using the ambient noise cross-correlation method. The group velocities have also been inverted for S-wave velocities using a simulated annealing algorithm. Thinner crust in the northern MER compared to the CMER is clearly imaged by changes in velocities in the 30-40 km depth range. The location of magmatic intrusions at some locations can be inferred from the presence of low S-wave velocity anomalies at mid-crustal levels, and the models also show interesting variations in velocities at lower crustal depths between parts of the MER and adjacent plateau crust. The cause of these velocity variations is uncertain and will be discussed.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2010
- Bibcode:
- 2010AGUFM.T31C2179K
- Keywords:
-
- 7205 SEISMOLOGY / Continental crust;
- 7270 SEISMOLOGY / Tomography;
- 8105 TECTONOPHYSICS / Continental margins: divergent