93. Geophysical observations, instrumentation, and techniques
93.30.-w Information related to geographical regions
93.30.Bz Africa
93.30.Ca Antarctica
93.30.Db Asia
93.30.Fd Australia
93.30.Ge Europe
93.30.Hf North America
93.30.Jg South America
93.30.Kh Large islands (e.g., Greenland)
93.30.Li Arctic Ocean
93.30.Mj Atlantic Ocean
93.30.Nk Indian Ocean
93.30.Pm Pacific Ocean
93.30.Qn Southern Ocean
93.30.Rp Regional seas
93.30.Sq Polar regions
93.30.Tr Temperate regions
93.30.Vs Tropical regions
93.55.+z International organizations, national and international programs
93.65.+e Data acquisition and storage
93.85.+q Instrumentation and techniques for geophysical research