Study of Seismic Risk Associated with Blasting at Limestone Quarries in Kano State, North West Nigeria

Blasting operations at limestone quarries in Kano State, North West Nigeria, generate ground vibrations and airblast overpressure that present seismic risk to surrounding communities and infrastructure. This study examines the seismic risk profile associated with blasting at three major limestone quarries near Kano metropolis. Vibration data were collected using triaxial seismographs deployed at distances from 200 to 2,000 metres from blast faces during 30 monitored blast events. Air overpressure was simultaneously measured using pressure transducers. Site-specific attenuation relationships were derived by regression analysis of the collected vibration data. Structural surveys of buildings in the influence zone and resident perception surveys were also conducted. Findings indicate that peak particle velocity attenuation rates in the Kano region are higher than commonly applied empirical constants, suggesting site-specific scaling is essential for blast design. Despite this, several blast events generated PPV levels exceeding 5 millimetres per second at distances under 400 metres, constituting a risk to masonry buildings. Resident surveys reveal widespread community anxiety and complaints regardless of measured vibration levels, indicating a perception gap requiring community engagement. Recommendations include adoption of site-specific blast design guidelines, deployment of permanent vibration monitoring systems, and community liaison committees. This study offers the first systematic seismic risk documentation for quarry operations in the Kano region. Keywords: blast vibration, seismic risk, limestone quarry, Kano State, peak particle velocity.