Modeling the 2-D seismic velocity structure across the Kenya rift

Braile, L. W.; Wang, B.; Daudt, C.R.; Keller, G. Randy; Patel, J. P.

doi:10.1016/0040-1951(94)90179-1

Cited by 35 publications

(23 citation statements)

References 7 publications

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“…In terms of deep structure, we cannot add much to the previous KRISP results (e.g., Maguire et al, 1994;Braile et al, 1994;Achauer et al, 1994) Fig. 10.…”

Section: Profile C-c 0 (23°n)mentioning

confidence: 77%

“…As discussed below, the width of the zone of lowdensity mantle narrows further in the Lake Baringo region. Braile et al, 1994) and extends eastward from longitude 35°E, crossing the Elgeyo Escarpment on the western flanks of the rift, the South Kerio basin, the Kamasia Range (a Pliocene horst block also called the Tugen Hills), the Baringo basin, and the eastern flank of the rift valley before ending at 37.5°E (Fig. 1).…”

Section: Profile C-c 0 (23°n)mentioning

confidence: 97%

“…In addition, the crustal thinning across the rift and upper mantle anomaly under the rift are symmetrical (e.g. Achauer et al, 1994;Braile et al, 1994;Maguire et al, 1994).…”

Section: Geologic and Tectonic Settingmentioning

confidence: 99%

“…Thus, densities for deep crustal and upper mantle units were estimated based on the P-wave velocities of the KRISP refraction profiles. The model along the rift axis was calculated using the axial seismic line as a constraint (Mechie et al, 1994;Henry et al, 1990), while in the cross-rift models the structure outside the rift was constrained by the cross-rift and flank seismic profiles Braile et al, 1994;Prodehl et al, 1994b). The velocity-density relations employed are based on the Nafe-Drake formula (Nafe and Drake, 1957): q = 0.52 + 0.3788V p , with an uncertainty of ±0.02 g/ cm 3 ; q is density and V p is compressional velocity (Henry et al, 1990;Barton, 1986).…”

Section: Density Constraintsmentioning

confidence: 99%

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An integrated geophysical study of the northern Kenya rift

Mariita

Keller

2007

Journal of African Earth Sciences

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“…In terms of deep structure, we cannot add much to the previous KRISP results (e.g., Maguire et al, 1994;Braile et al, 1994;Achauer et al, 1994) Fig. 10.…”

Section: Profile C-c 0 (23°n)mentioning

confidence: 77%

Section: Profile C-c 0 (23°n)mentioning

confidence: 97%

“…In addition, the crustal thinning across the rift and upper mantle anomaly under the rift are symmetrical (e.g. Achauer et al, 1994;Braile et al, 1994;Maguire et al, 1994).…”

Section: Geologic and Tectonic Settingmentioning

confidence: 99%

Section: Density Constraintsmentioning

confidence: 99%

See 2 more Smart Citations

An integrated geophysical study of the northern Kenya rift

Mariita

Keller

2007

Journal of African Earth Sciences

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“…4, it can be seen that the strongest correlation is obtained for a structural index of 0.5. We have also varied both parameters (structural index and window size) simultaneously over the full range of plausible values and do not find better fits Stuart & Zengeni (1987) Zimbabwe Refraction Keller et al (1994) Kenya Refraction Mechie et al (1994) Kenya Refraction Wright et al (2003) South Africa Refraction Kwadiba et al (2003) South Africa Refraction Green & Durrheim (1990) South Africa Refraction Buness et al (1992); Mickus & Jallouli (1999) North Africa Refraction Doser et al (1997) North Africa Refraction Seber (1995) North Africa Refraction Maguire et al (1994) Kenya Refraction Braile et al (1994) Kenya Refraction between the seismic-and gravity-based estimates of Moho depth than shown in Fig. 4 for a structural index of 0.5.…”

Section: Structural Index and Window Sizementioning

confidence: 98%

A crustal thickness map of Africa derived from a global gravity field model using Euler deconvolution

Tedla

Meijde

Nyblade

et al. 2011

Geophysical Journal International

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S U M M A R YWe develop a new continental scale crustal model for Africa by modelling the free-air gravity anomaly EIGEN-GL04C, which was developed from 30 months of GRACE Level 1B data covering the period from 2003 February to 2005 July, and surface gravity data from seven different sources. From this gravity model, crustal thickness is estimated using 3-D Euler deconvolution, a method that does not rely on a priori depth and density constraints. The results are in good agreement (i.e. within 5 km) of seismically determined Moho depth estimates from across the continent, except for narrow tectonic regions, such as rift valleys, and areas where seismic velocity models of the crust indicate a gradational Moho. The results show that crustal thickness is fairly homogeneous, with an average crustal thickness for the whole continent of 39 ± 2(SD) km. The average Moho depth for most terrains is within 5 km of the continental average, and there is little variability between terrains of different age. The average thickness for Archean, Proterozoic and Palaeozoic crust is 39, 39 and 41 km, respectively. Crustal thickness in sedimentary basins across northern and central Africa varies between 33 and 36 km. Through comparison with global averages for similar-aged terrains, we find that African crustal thickness does not deviate significantly from the thickness of crust in other parts of the world.

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New insights into the crust and lithospheric mantle structure of Africa from elevation, geoid, and thermal analysis

et al. 2016

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We present new crust and lithosphere thickness maps of the African mainland based on integrated modeling of elevation and geoid data and thermal analysis. The approach assumes local isostasy, thermal steady state, and linear density increase with depth in the crust and temperature‐dependent density in the lithospheric mantle. Results are constrained by a new comprehensive compilation of seismic Moho depth data consisting of 551 data points and by published tomography models relative to LAB depth. The crustal thickness map shows a N‐S bimodal distribution with higher thickness values in the cratonic domains of southern Africa (38–44 km) relative to those beneath northern Africa (33–39 km). The most striking result is the crustal thinning (28–30 km thickness) imaged along the Mesozoic West and Central African Rift Systems. Our crustal model shows noticeable differences compared to previous models. After excluding the Afar plume region, where the modeling assumptions are not fulfilled, our model better fits the available seismic data (76.3% fitting; root mean square error = 4.3 km). The LAB depth map shows large spatial variability (90 to 230 km), with deeper LAB related to cratonic domains and shallower LAB related to Mesozoic and Cenozoic rifting domains, in agreement with tomography models. Though crustal and lithosphere thickness maps show similar regional patterns, major differences are found in the Atlas Mountains, the West African Rift System, and the intracratonic basins. The effects of lateral variations in crustal density as well as the nonisostatic contribution to elevation in the Afar plume region, which we estimate to be ~1.8 km, are also discussed.

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Modeling the 2-D seismic velocity structure across the Kenya rift

Cited by 35 publications

References 7 publications

An integrated geophysical study of the northern Kenya rift

An integrated geophysical study of the northern Kenya rift

A crustal thickness map of Africa derived from a global gravity field model using Euler deconvolution

New insights into the crust and lithospheric mantle structure of Africa from elevation, geoid, and thermal analysis

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