Affiliation:
1. Geodesy and Geodynamics Research and Development Department , Space Science and Geospatial Institute (SSGI) 33679 Minilik Avenue II , Addis Ababa , Ethiopia
Abstract
Abstract
The northern part of the East African Rift System is characterized by depleted Moho depth and thermally thinned lithosphere. This research aims to determine the Moho depth of the study area through non-linear gravity inversion and cross-validation with seismic Moho estimates. The study utilized gravity data to obtain the gravity anomaly of the Moho interface, a topographic grid for removing topographic effects, a crustal model to determine total sediment thickness and its gravitational effect, and seismic Moho depth for constraining the forward model and cross-validation. The estimated Moho depth of the study area ranges between 5 km (in the Indian Ocean) to 45 km (in the Ethiopian Highlands), with slight variation compared to seismic Moho relief. This is because the reference level, calculated for the thinner part of the study region, underestimates the entire area. Upwelling magma in the Eastern branches of the EARS may also incur slight variation in the estimated Moho depth; rifting, volcanism, melt intrusion, magmatic uplift, and tectonic setting all influence the Moho depth of the study area. Furthermore, reverberations affect most seismic Moho estimations in the region. The slight variation can be mitigated by improving the gravity network for accurate validation and precise heat flow measurement to correctly identify magmatic anomalies and density contrasts. Additionally, applying reverberation removal techniques in the study region could improve seismic Moho estimation.
Subject
Earth and Planetary Sciences (miscellaneous),Engineering (miscellaneous),Modeling and Simulation
Reference76 articles.
1. Steinhart, JS. Mohorovicic discontinuity. In: Runcorn, SK, editor. International dictionary of geophysics, vol 2. Oxford: Pergamon Press; 1967:991–4 pp.
2. Reguzzoni, M, Sampietro, D, Sanso, F. Global Moho from the combination of the CRUST2.0 model and GOCE data. Geophys J Int 2013;195:222–37. https://doi.org/10.1093/gji/ggt247.
3. van der Meijde, M, Fadel, I, Ditmar, P, Hamayun, M. Uncertainties in crustal thickness models for data sparse environments: a review for South America and Africa. J Geodyn 2015;84:1–18. https://doi.org/10.1016/j.jog.2014.09.013.
4. Bouman, J, Ebbing, J, Fuchs, M. Reference frame transformation of satellite gravity gradients and topographic mass reduction. J Geophys Res Solid Earth 2013;118:759–74.
5. Kvas, A, Mayer-Gürr, T, Krauss, S, Brockmann, J, Schubert, T, Schuh, W, et al.. The satellite-only gravity field model GOCO06s. GFZ Data Services; 2019.