Subsurface Investigation of Cape Kolka, Latvia : A Progradational Strandplain Along the Baltic Coast

Abstract

The Cape Kolka strandplain is located along the northern tip of Latvia, situated between the Baltic Sea and the Gulf of Riga. The strandplain has been prograding due to excess sediment being carried northwards through longshore drift from erosion due to sea levels rise. The project utilizes ground penetrating radar (GPR) which emits electromagnetic pulses into the subsurface that reflect off layers and are then recorded at the surface. A Sensors and Software pulseEKKO Pro GPR system was used with 100 and 500 MHz antennae frequencies. The data was collected along a 1,000 m sandy road that is perpendicular to the coast and 37.6 km from the northern tip. To geometrically correct the GPR profiles, a topographic profile was collected with a TopCon RL-H₃CL laser leveler along the road at intervals of 5 m. Profiles were collated and processed using EKKO Project software using AGC gain, a velocity of 0.069 m/ns, dewow, and grey color palette. The dipping reflection facies include prograding stratigraphy that are interpreted as former beach faces. The results will provide a better understanding of coastal strandplains and how to better manage these sensitive environments in light of rising sea levels and associated erosion.