Geological and oceanographic survey methods, illustration

Geological and oceanographic survey methods. Schematic illustration showing different techniques used to investigate changes along coastlines and on sea floors. Acoustic instruments (sidescan sonar, swath bathymetry and hydrophone profilers) provide information on topography and the distribution of sediments. On land, ground-penetrating radar (GPR) determines the thickness and structure of sediment beneath sand dunes. Direct sampling (such as GeoProbe) determines sediment grain size, composition, and age. Short-term changes in beach morphology are recorded on land and at sea, part of the Beach Erosion Research and Monitoring (BERM) program. Aerial photography and Light Detection and Ranging (LIDAR) are used to survey changes along the coast. Differential Global Positioning Systems (DGPSs) are used to geolocate data.