Empirical relationships of earthquake magnitude scales and estimation of Guttenberg–Richter parameters in gulf of Guinea region

Abstract

Attempts have been made to investigate the relationships between various earthquake magnitude scales for the region of the Gulf of Guinea, namely moment magnitude (Mw), surface wave magnitude (Ms), body wave magnitude (mb) and local magnitude (ML). The study involves a sum of 535 earthquake data from the period of 1918 to 2016. It was found that Ms−Mw;Mw−ML and mb−Mw scales are in fairly good agreement while mb−Ms magnitude scale differs by a magnitude unit of 1.45. Since the region of study is seismically active and mainly under the ocean, comprising of the mid-Atlantic ridges and the plate boundary, the seismo-tectonics of the study region is inferred from the obtained Gutenberg-Richter (GR) recurrence parameters. The inferences made are the prime input to the seismic hazard assessment of the region. Keywords: Magnitude scales, Empirical relationships, Gulf of Guinea, West Africa