Probabilistic Seismic Hazard Assessment for the Main Cities Along the Continental Section of the Cameroon Volcanic Line

Abstract

AbstractThe Cameroon Volcanic Line (CVL) is located in the Gulf of Guinea. It is an alignment of volcanic islands and continental volcanoes that extend over a distance of nearly 1600 km. One of the hypotheses of its origin suggests that volcanism was guided by faults that are covered by lava flows, making it difficult to identify them. Moderate seismicity is associated with CVL, especially at the level of Mt Cameroon, an active volcano where damage has often been observed on buildings due to the earthquakes. To date, no studies have been carried out to evaluate the seismic risks in this area. This is the main reason behind conducting the current study using a probabilistic approach. Geology, tectonics geophysics and local seismicity were used to map three seismic source zones. The recurrence model is that of Gutenberg and Richter; and choosing ground motion prediction equations corresponding to an active continental crust, we were able to calculate the occurrence probability if the intensity of the ground motion is greater than a precise value for a given period. So for a return period of 475 years, we calculated the PGA for eleven (11) cities, spreading along the CVL. The results show that Buea, located at the foot of Mt. Cameroon, has a PGA of 10% g. This value decreases as one moves away from it, such that at Bamenda-Bafoussamabout 200 km northeast of Buea, the PGA is of the order of 5% g.KeywordsCameroon Volcanic LineEarthquakesProbabilistic seismic hazard assessmentGround motion prediction equation