Seismic Refraction Profiles from Port Royal Beach in Jamaica

The study’s goal is to constrain spatiotemporal changes to the seismic velocities at Port Royal Beach, Jamaica. We used Passcall Instrument Center’s 24-channel refraction survey equipment (Geometrics Geode, shot trigger, geophones, and associated cables) to collect reverse vertical and horizontal-component seismic refraction profiles at four locations along the beach (sites 1-4). The geophones have corner frequencies of 4.5 Hz. The source for all vertical-component surveys was a 16 lb hammer that strikes an aluminum plate ten times to increase the signal-to-noise ratio. The source for the horizontal-component surveys was either an iron stake that we hit into the ground at a 45-degree angle. To constrain seismic velocity within the vadose zone, we set the receiver spacing to 0.3 m and the source offset was 0.3-19 m (incrementing by 3 m). To constrain seismic velocities within the upper 30 m, we set the receiver spacings to 1.5 m and shot offsets of either 1.5 m, 7 m, 29 m, or 28.1 m. We produce shots on both sides and within the centers of the receiver arrays. The survey identifiers, source offsets, receiver spacings, sampling rate, trace numbers, trace lengths, and shot directions are in the header of each seismic refraction profile.