Mobile nodes within Wireless Sensor Networks (WSNs) open up new challenges such as improved energy efficiency, coverage, target tracking, and fault tolerance. We propose a novel Chain-Based Relocation Approach (CBRA) to relocate mobile sensor nodes from their initial positions within a Region Of Interest (ROI) to cover a particular event happening outside the initial deployment zone called Center a Of Interest (COI). CBRA uses a grid quorum-based solution to propagate the redundant nodes present within the ROI. We propose an energybased redundant node selection procedure to ensure a balanced energy consumption among the redundant nodes regardless of the location of the redundant nodes with respect to the COI. We evaluate the performance of the CBRA solution using the WSNet simulator. Simulation results show that the network energy consumption and the relocation time increase as the distance separating the COI from the ROI increases. Moreover, the whole network energy consumption improves with the network density while the relocation time decreases with increasing speed of sensor nodes.