The compact glacial tills and underlying sandstone around Portlaoise can trick you into thinking the ground is uniformly stable. But once you start mapping shear-wave velocities across the townland, the picture changes fast. We’ve measured Vs30 values swinging from stiff soil profiles near the Triassic bedrock outcrops south of the M7 to softer basin fills toward the River Barrow floodplain. That contrast is exactly why seismic microzonation matters here—the same earthquake produces different shaking just two kilometers apart. Our lab runs the borehole arrays, MASW lines, and resonant column tests that feed the hazard maps, working with the Eurocode 8 framework and the Geological Survey Ireland’s national mapping programme. Before site classification turns into a guess, we pair the seismic survey with a CPT test to anchor the dynamic properties to measured penetration resistance.
Microzonation isn’t just about mapping hazard—it’s about finding the pockets of stiff ground within a softer basin so you can place critical infrastructure where amplification is lowest.
