Many projects investigating coastal landscapes commonly base their results on morphology, drill core, available outcrops, and/or models.Ground penetrating radar (GPR) provides a methodology that enables one to image the subsurface coastal stratigraphy in a near-continuous, time-effective, non-destructive and non-invasive manner. The paper will discuss how this field of research was initiated and present GPR case studies along various marine and lacustrine shorelines worldwide including theUnited States, Lithuania, New Zealand, Canada, and China.
GPR is an electromagnetic (EM) geophysical tool that enables one to image (2D & 3D) the subsurface stratigraphy of coastal environments. The GPR acquisition systems used for the study were pulseEKKO 100 & 1000 with antennae frequencies ranging from 25 MHz to 450 MHz and transmitter voltages ranging from 200 volt to 1000 volt. Step sizes and antennae separation varied depending on antennae frequency chosen and on the site conditions. The digital profiles were processed and plotted using pulseEKKO software. Depths of deposits were calculated using near surface velocity measurements from collected common midpoints.
Radar stratigraphic analysis on the collected data provided the framework to investigate both lateral and vertical geometry and stratigraphy of the coastal deposits. GPR profiles, with varying depths of penetration (~4m to > 50 m), reveal patterns showing coastal growth by aggradation and/or progradation as well as features showing coastal erosion. Interpretations of the results suggest that several different coastal processes are at work including longshore transport, changes in sediment supply, and response to sea level changes.
