Further constraints on the shear wave velocity structure of Cameroon from joint inversion of receiver function, Rayleigh wave dispersion and ellipticity measurements

Crustal Thickness Variations and Tectonic Settings in the Southwest Cameroon Inferred from Gravity and Topography Data

“…The average depth of the Moho boundary (Equation ( 1)) calculated from the slope of the linear segment that fits the data is 39 ± 3:44 km. This result is in agreement with recent seismological studies [1,33,74]. As our study area is dominated by the CC, it is important to remind that our results also join those of [75].…”

“…The comparison between our results with those obtained from previous seismological studies reveals some correlation and divergence dependent on the data used and their pro-cessing. Beneath the coastal plain (CM01, CM05) and the PAB (CM10, CM12, and CM17), our computation is in agreement with [33,74]; the difference in terms of terrain average does not exceed ±2:62 km both beneath the coastal plain and the PAB. Beneath the CC (CM06, CM04), our results also closely agree with those published by [33] with a minor difference of 0.18 km on average; concerning [1,74] the differences in the same area are about -5.1 km and -4.25 km, respectively.…”

“…Numerous gravity and seismological studies have been conducted to investigate the internal lithospheric structure of the Southwest region of Cameroon by mapping the Moho depth. Some resulting Moho depth map has been interpreted in terms of seismic wave propagation and seismic tomographic imaging [1,[30][31][32][33]. For example, the study of [30] revealed that thick crust and fast upper mantle velocities are observed beneath cratons.…”

“…Later, [1], by using 1D shear wave velocity models, estimated the crustal thickness of (35-40 km) beneath the Southern CVL, a thicker crust (43-48 km) within the CC and a thinner crust (26-31 km) beneath the West coastal zone. More recently, the regional study of [33] revealed a crustal thickness is increasing from 28 km in the Garoua rift to 42 km within the CC, while beneath the CVL and the PAB, the crustal thickness varies between 33 and 40 km. These authors also compare the topography and the crustal thickness in Cameroon.…”

Shallow Crustal Shear Velocity and Vp/Vs Across Southern California: Joint Inversion of Short‐Period Rayleigh Wave Ellipticity, Phase Velocity, and Teleseismic Receiver Functions

“…In order to provide a model with resolution of Vs and Vp/Vs in the upper few km, we combine the complementary sensitivities of Rayleigh‐wave phase velocities (upper crust), ellipticity (upper few km), and the initial pulse of teleseismic receiver functions (shallow Vp/Vs ratio and shallow interfaces) to create a self‐consistent model at the regional scale across southern California. The idea to combine receiver functions and surface wave data in a Bayesian joint inversion to determine Vs and Vp/Vs is relatively new (Dreiling et al., 2020; Ojo et al., 2019), and only recently shown to be promising in resolving near‐surface Vs and Vp/Vs in sediments (Li et al., 2019). By including Vp/Vs as a parameter we are able to fit receiver functions on a regional scale for the first time across 231 Southern California stations, including in basins where receiver functions have long been discarded as nuisance signals or “corrected” with ad‐hoc models, as reverberations overprint Moho and other crustal signatures (e.g., Yeck et al., 2013).…”