Ground Penetrating Radar (GPR) Data - Old Bar Beach Survey

Brief description

This record contains processed and topographically corrected Ground Penetrating Radar (GPR) data (.segy, .bmps) and summary shapefile collected on fieldwork at Old Bar Beach, NSW for the Bushfire and Natural Hazards CRC Project, Resilience to Clustered Disaster Events on the Coast - Storm Surge. The data was collected from 3 - 5 March 2015 using a MALA ProEx GPR system with a 250 MHz shielded antennae. The aim of the field work was to identify and define a minimum thickness for the beach and dune systems, and where possible depth to any identifiable competent substrate (e.g. bedrock) or pre-Holocene surface which may influence the erosion potential of incident wave energy. Surface elevation data was co-acquired and used to topographically correct the GPR profiles. This dataset is published with the permission of the CEO, Geoscience Australia.

Lineage

Maintenance and Update Frequency: notPlanned

Statement: Data was collected between the 2-5 March 2015 using a MALA GPR system with a 250 MHz shielded antennae. GPR survey lines and elevations were co-acquired using a NovAtel SMART6-L Global Positioning System (GPS) receiver that recorded location measurements at one per 4 seconds or better. Due to the inherent inaccuracy introduced by the backpack GPS receiver setup, and the resultant inability to maintain a consistent distance or height with respect to the antenna, differential correction of GPS measurements was not attempted. Accordingly all elevation and location coordinates are relative. The raw data was processed and converted to SEGY format using RadExplorer(TM) software (Geomatrix Earth Science Ltd). Processing involved the following processing flow and settings. 1. DC removal: Start Time - 130; End Time - 162; Mode - Mean 2. Time zero adjustment: Manual - selected the first return 3. Background removal: Normal - The fifth weakest option 4. 2D Spatial filtering: Filter Type - 2D Mean; Number of Traces - 3; Number of Samples - 2; Filter Mode - Normal 5. Amplitude correction: AGC; Operator Length (ns) - 50; AGC Scalar - Mean; Scalar Application - Leading 6. Bandpass filtering: Low Cut - 71 MHz; Low Pass - 135 MHz; High Pass - 378 MHz; High Cut - 750 MHz 7. Topographic correction: elevation correction using the associated .cor file to account for surface topographic variation 8. Trace Edit: Where topographic correction was noisy, some individual traces were erased to smooth the profile.