Characteristics of the Mount Cameroon seismicity for the 2005–2015 period (Cameroon, West-Central Africa).

Mount Cameroon is an active volcano located in Central Africa. This study was aimed at analyzing the b-value and the fractal dimensions in order to ascertain the dynamics of this volcano complex. A local seismic network in the southwest region of Cameroon (Ekona-Buea) recorded the volcano-seismic activity data during the years 2005–2015. More than 1000 microearthquakes recorded during this period were located using the Hypocenter code. The b-value of the Gutenberg-Richter law was calculated using the Aki (1965) method. Analyses realized of these microearthquakes show a well-defined seismic pattern which are characterized by single and swarm earthquakes with duration magnitudes (MD) of 0.5 ≤ MD ≤ 3.0 down to a depth of 65 km. Three distinct clusters of weak (MD < 3) earthquakes occurred at the summit plateau and northwest and southeast flanks of Mount Cameroon. These clusters of seismic events align with four lithospheric fault zone trending in the SSW-NNE, N-S, SW-NE, and NW–SE directions. Deep (20–65 km) earthquakes on the southeast flank show lower frequency (f) content, with 2 ≤ f ≤ 4 Hz for 2.0 ≤ MD ≤ 2.9. Nonvolcanic earthquakes of 2005–2011 present a unimodal Gutenberg-Richter law, with b-values ranging from 1.06 ± 0.11 to 1.29 ± 0.17. Constants b > 1 could indicate a hydraulic fracturation mechanism, resulting from the movements of magma. However, the Gutenberg-Richter law does not match the recordings of the 2012–2014 period, due to the magnitude distribution. Temporal monofractal dimensions are nearly constant for a few days during the first five main seismic energy peaks and decrease abruptly just after these maxima. This behavior reveals the self-organization of earthquakes that follows main seismic peaks. The results of our work could be implemented in the future in the volcanic monitoring system. [ABSTRACT FROM AUTHOR]