%0 Journal Article %1 novak_etal:1997 %A Novak, O. %A Prodehl, C. %A Jacob, A. W. B. %A Okoth, W. %D 1997 %J Tectonophysics %K geophysics seismics %N 1-4 %P 171--186 %R 10.1016/S0040-1951(97)00100-5 %T Crustal structure of the southeastern flank of the Kenya rift deduced from wide-angle P-wave data %U http://dx.doi.org/10.1016/S0040-1951(97)00100-5 %V 278 %X The 420-km-long northwest-southeast KRISP (Kenya Rift International Seismic Project) flank line F, part of the KRISP 94 experiment, extends from Athi River (30 km southeast of Nairobi) to the Indian Ocean near Mombasa, Kenya. Line F crosses the Chyulu Hills area, a young Quaternary volcanic field, surrounded by the basement of the Mozambique belt. The basement is at the surface almost along the entire profile with two exceptions, one in the Chyulu Hills area due to the presence of volcanic pyroclastics, the other next to the Indian Ocean where sediments reach a thickness of about 8 km. Below the basement the crust can be divided into three layers. The upper layer extends to about 10 km depth with P-wave velocities of roughly 6.25-6.4 km/s. The mid-crustal layer reaches a depth of about 20 km where P-wave velocities range from 6.55 km/s to 6.7 km/s. The lower crust in the area of the Chyulu Hills is unexpectedly thick (>20 km) and generates strong refracted phases with velocities of about 7.0 km/s. Crustal thickness is about 40 km but thickens in the area of the Chyulu Hills and thins towards the Indian Ocean to 22 km. Pn-phases, refracted waves travelling through the uppermost mantle, are identified on four record sections and give good control over the upper mantle velocities which are slightly reduced from 8.1-8.2 km/s to 7.9 km/s underneath the Chyulu Hills area. The upper and lower crust in the region of the Chyulu Hills are significantly heterogeneous, producing strong signal-induced noise which masks secondary arrivals in the corresponding distance range. Underneath the Chyulu Hills PMP-reflections are hard to identify indicating that the crust-mantle boundary is a transition zone, rather than a first-order discontinuity.

@article{novak_etal:1997, abstract = {The 420-km-long northwest-southeast KRISP (Kenya Rift International Seismic Project) flank line F, part of the KRISP 94 experiment, extends from Athi River (30 km southeast of Nairobi) to the Indian Ocean near Mombasa, Kenya. Line F crosses the Chyulu Hills area, a young Quaternary volcanic field, surrounded by the basement of the Mozambique belt. The basement is at the surface almost along the entire profile with two exceptions, one in the Chyulu Hills area due to the presence of volcanic pyroclastics, the other next to the Indian Ocean where sediments reach a thickness of about 8 km. Below the basement the crust can be divided into three layers. The upper layer extends to about 10 km depth with P-wave velocities of roughly 6.25-6.4 km/s. The mid-crustal layer reaches a depth of about 20 km where P-wave velocities range from 6.55 km/s to 6.7 km/s. The lower crust in the area of the Chyulu Hills is unexpectedly thick (>20 km) and generates strong refracted phases with velocities of about 7.0 km/s. Crustal thickness is about 40 km but thickens in the area of the Chyulu Hills and thins towards the Indian Ocean to 22 km. Pn-phases, refracted waves travelling through the uppermost mantle, are identified on four record sections and give good control over the upper mantle velocities which are slightly reduced from 8.1-8.2 km/s to 7.9 km/s underneath the Chyulu Hills area. The upper and lower crust in the region of the Chyulu Hills are significantly heterogeneous, producing strong signal-induced noise which masks secondary arrivals in the corresponding distance range. Underneath the Chyulu Hills PMP-reflections are hard to identify indicating that the crust-mantle boundary is a transition zone, rather than a first-order discontinuity.}, added-at = {2012-09-01T13:08:21.000+0200}, author = {Novak, O. and Prodehl, C. and Jacob, A. W. B. and Okoth, W.}, biburl = {https://www.bibsonomy.org/bibtex/2db7a45cfe4177078e62df76bf990ac06/nilsma}, day = 15, doi = {10.1016/S0040-1951(97)00100-5}, interhash = {4d47ce9af391c622aaf51ee7a18d4206}, intrahash = {db7a45cfe4177078e62df76bf990ac06}, issn = {00401951}, journal = {Tectonophysics}, keywords = {geophysics seismics}, month = sep, number = {1-4}, pages = {171--186}, timestamp = {2021-02-09T13:27:11.000+0100}, title = {Crustal structure of the southeastern flank of the Kenya rift deduced from wide-angle P-wave data}, url = {http://dx.doi.org/10.1016/S0040-1951(97)00100-5}, volume = 278, year = 1997 }