A GROUND-PENETRATING RADAR STUDY OF ACTIVE LAYER THICKNESS IN AREAS OF MOIST SEDGE AND WET SEDGE TUNDRA NEAR BETHEL, ALASKA, USA

Ground-penetrating radar (GPR) techniques were used near Bethel, Alaska, to compare the thicknesses of the active layer between areas of moist sedge and wet sedge tundra. Once set up in the field, the GPR provided a rapid, accurate, and effective means for determining the depth to frozen soil and the thickness of the active layer. In areas of silty soil, the average thickness of the active layer under wet sedge tundra (64 cm) was considerably deeper than under moist sedge tundra (38 cm). In areas of moist edge tundra underlain by silty soils, depths to frozen soil layers were relatively shallow with active layer thicknesses ranging from 17 to 63 cm. -Authors