The presence of the Lg earthquake surface-wave phase, which is indicative of continental structure between the epicenter and recording station, is used in the exploration of Arctic regions. Water-covered areas of continental structure include the Canadian archipelago, parts of Baffin Bay and Davis Strait, the Barents Sea, Bering Strait, and the shallow parts of the Bering and Greenland seas. Areas of noncontinental structure include the Arctic Ocean, Beaufort Sea, Norwegian Sea, and the deep parts of the Bering and Greenland seas.