About 10,000 miles of seismic reflection data over an area of the northern Bering Sea shelf, known as Norton Sound, has been mapped. This area is bounded by the Seward Peninsula on the north, St. Lawrence Island on the west, and the coastline that rims Norton Sound on the south and east.

Interpretion of seismic data reveals three separate basins on the basis of the structural mapping following the acoustic basement of the strata. The main basin, informally named the Norton Basin, is located slightly west of Nome with northwest-southeast trending elongated configuration. Two other separate and smaller basins, informally named the South Nome Basin and the North Yukon Basin respectively, are located on the east side of the Norton Basin. These basins are dominated by numerous normal faults that form horsts and grabens as deep as 5 to 6 kilometers. The age of the basin fill is unknown, probably Cenozoic based on the seismic velocities. The ages of the floor rocks are also not known; the rocks could be as young as Mesozoic or as old as Paleozoic or older.

The well-known Kaltag fault, a major strike-slip fault showing between 60 and 130 kilometers of right-lateral separation as observed in the Yukon-Koyukuk area onshore, cannot be detected westward from the seismic reflection data.

The hydrocarbon potential of these basins may be of three types: anticlines, fault traps, and stratigraphic traps. Reflections showing amplitude anomalies which could be interpreted as sandstones are observed in the deeper portions of the basin.