Near-field seismic wave attenuation and local magnitude calibration based on controlled blasting experiments

With the increasing depth and intensity of coal mining in China, non-natural seismic events occur more frequently, posing higher demands on mine safety and seismic monitoring. As a core parameter in earthquake monitoring and hazard assessment, precise determination of magnitude is essential for predicting and mitigating dynamic disasters. To address this, we conducted 22 controlled blasting experiments in the Weihai Port area of Shandong Province, using a combination of fixed and mobile seismic stations to systematically investigate the attenuation characteristics of near-field seismic waves and to establish a regional calibration function for local magnitude (ML). The calibration functions for both horizontal and vertical components were derived through least-squares fitting, from which the corresponding local magnitude determination formula was developed. Results from the 22 blasting events indicate good consistency of single-station magnitudes, with small deviations compared to the magnitudes determined by the Shandong Seismic Network, satisfying the required accuracy for magnitude estimation. Overall, this study establishes a calibration function applicable within 5 km of the Weihai blasting area, enhancing the consistency between magnitudes of blasting and natural earthquakes. The results provide a valuable reference for improving regional seismic monitoring systems and strengthening early warning capabilities for mine-related hazards.