Strain rate field on the Nigeria lithosphere derived from GNSS velocity

Abstract

The Global Navigation Satellite System (GNSS) over the years has become an essential instrument in modelling geodynamic processes, because of its high spatio-temporal characteristics. Accurate velocity modelling of GNSS stations and strain rate analysis can provide an accurate mechanism for studying the deformation of the earth crust. Therefore, this study presents the strain rate tensor of the Nigeria crust from GNSS network, but first, the GAMIT/GLOBK was used to process and obtain accurate velocity solution of the Nigerian Permanent GNSS Network (NigNET). The surface deformation of Nigeria deduced from strain analysis was computed using splines in tension. The results revealed that the highest extensional and compressional strain rates of up to 2.67 to 2.89μstrain/year were observed around parts of the north-west (Jigawa, Kaduna and Kano) and north central region (parts Abuja and Jos) and some parts of the north-east (parts of Bauchi and Gombe), while the lowest minimal or low extensional and compressional strain rates of 0.09 to 0.534μstrain/year were observed around some parts of the north central (parts of Kwara and Niger) and parts of north-west (parts of Kebbi, Zamfara and Sokoto). The highest maximum shear strain rate of about 0.4μstrain/year which has its peak around some parts of Kaduna, Abuja, Plateau and Bauchi was observed. The highest areal dilatation rate observed in Nigeria is about 1.02μstrain/year. The study serves as a benchmark for further studies.