Assessment of Blast Vibration Effects on Residential Structures Near Quarry Sites in Ogun State, South West Nigeria

Quarry blasting in peri-urban zones of Ogun State, South West Nigeria, has generated increasing community concern regarding structural damage to residential buildings from ground vibration. This study assesses blast-induced ground vibration levels and their potential impact on nearby residential structures across three active quarry sites in Ogun State. Peak particle velocity (PPV) measurements were recorded using seismographs at varying distances from blast points during 25 controlled blast events. Structural inspections of 80 residential buildings within a two-kilometre radius were conducted to document visible damage patterns. Measured PPV values were compared to the United States Bureau of Mines (USBM) and British Standards Institution damage threshold criteria. Findings indicate that PPV values at distances below 500 metres frequently exceeded safe thresholds, particularly for older masonry structures. Cracks in walls, floors, and foundations were identified as the predominant damage types. The study highlights deficiencies in blast design, particularly excessive instantaneous charge weights, as a primary cause. Recommended mitigation measures include the implementation of electronic delay detonation systems, reduction of maximum instantaneous charge, and the establishment of exclusion zones for sensitive receptors. This research supports the need for enforceable blast monitoring protocols under Nigeria's mining regulations and offers a scalable assessment framework for operators. Keywords: blast vibration, peak particle velocity, quarry, Ogun State, structural damage.