Did Anthropogenic Activities Trigger the 3 April 2017 Mw 6.5 Botswana Earthquake?

Abstract

n 3 April 2017, a Mw 6.5 earthquake occurred in Botswana, representing the second-strongest earthquake registered since 1949. Such an intraplate event occurred in a low seismic hazard area and was suspected to be an artificial earthquake induced by nearby anthropogenic activities (gas extraction). The possible relation between anthropogenic activities and the earthquake occurrence has been qualitatively investigated. We estimated the geometric and kinematic characteristics of the causative fault from the modeling of Sentinel-1 InSAR interferograms. Our best-fit solution for the main shock is represented by a normal fault located at a depth greater than 20 km, dipping 65° northeast, with a right-lateral component, and a mean slip of 2.7 m. The retrieved fault geometry and mechanism are incompatible with the hypothetical stress perturbation caused by the anthropogenic activities performed in the area. Therefore, the 3 April 2017 Botswana earthquake can be classified as a natural intraplate earthquake.