AN INVESTIGATION INTO SEISMIC ANISOTROPY IN TERMS OF P-WAVE VELOCITY AND PEAK PARTICLE ACCELERATION AT MELTON ROSS CHALK QUARRY

This project’s objective is to explore the seismic effects of blasting within the Creataceous Chalk within the Melton Ross Quarry in Lincolnshire, United Kingdom. With the use of GPS enabled vibration monitors, seismic anisotropy is to be determined if it is present within the quarry. Seismic anisotropy refers to the directional dependence of seismic wave speeds and particle motion polarizations, as well as the splitting of normal modes, as caused by the elastic properties of rocks.

Data will be collected through FM 301 blasting seismographs that Blast Log Ltd placed at strategic locations around the detonation sites within the quarries. These seismographs will record particle acceleration time domain traces, enabling the determination of key seismic parameters such as attenuation of peak particle accelerations with distance and P-wave velocity. Rock properties including unconfined compressive rock strength (UCS), uniformity of rock, density and Poisson’s ratio have shown a direct corelation to P-wave velocity when blasting. If possible, tests will include the determination of static or dynamic Young’s modulus. Therefore, laboratory testing has been set to determine rock mechanic characteristics of samples from each of the quarries.

The deployment of seismographs will synchronize with the detonation blasting borehole(s) to provide precise timing data. The project will require the usage of a variety of skills including GPS surveying for accurate positioning of seismographs, and the use of Vulcan software to make 3D models of the quarries. The Vulcan 3D geological software will be used to create a block model and the location of blasting boreholes.