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Assessing Seismic Hazard for the Democratic Republic of Congo and Its Vicinity Based on New Seismic Zoning Source Model

2022; Springer International Publishing; Linguagem: Inglês

10.1007/978-3-030-73026-0_17

2522-8722

Georges Mavonga, Jeanpy Lukindula, Raymond Durrheim,

Seismic Waves and Analysis

The DRC encompasses both intra-plate and active tectonic areas associated with the Congo Craton and the western branch of the East African Rift System, respectively. The seismic hazard assessment is based on the new Sub-Saharan-Global Earthquake Model earthquake catalogue (SSA–GEM) with homogeneous magnitude representation. The final declustered catalogue spans 55 years (from 1960 to 2015) with 398 events and a magnitude of completeness of about 4.5. The maximum credible magnitude of earthquakes was determined using the entire catalogue from 1900 to 2015. The seismotectonic zonation into 15 seismic source zones was done on the basis of the regional geological structure, neotectonic fault systems, distribution of thermal springs, regional strain rate model developed for the East African Rift by Saria and earthquake epicenters. The Gutenberg Richter parameters were determined using Aki's maximum likelihood method Aki (Bulletin of the Earthquake Research Institute, Tokyo University, 43, 237-239, 1965) and Weichert's method Weichert (Bulletin of the Seismological Society of America, 70, 1337-1346, 1980), which were compared with extension of the Aki-Utsu b value estimator for incomplete catalogues by Kijko and Smit. Hazard computations were performed using the Open Quake engine (version 2.7.0-1). The peak Ground Acceleration and spectral acceleration at periods of 0.05, 0.1, 0.2, 0.5, 1 and 2s were calculated using 4 Ground Motion Prediction Equations: two for active shallow crust and two for stable continental conditions for soil sites corresponding to Vs30 = 600, 760 and 1500 m/s at 11 cities of the DRC and surrounding areas. The results are consistent with those obtained using the regional frequency-independent attenuation law using Crisis 2012 software.