Gamma Probe dan Counting System
Gelas vulkanik (volcanic glass)
Gelombang Akibat Angin (Wind Wave)
Gelombang Melawan Arus (Bores)
Gelombang Pasang Akibat Badai (Storm Surge)
Gelombang piroklastik (pyroclastic surge)
Gempa vulkanik (volcanic earthquake)
Geotermal atau panas bumi (geothermal)