A gravity meter has been used for exploring subsurface mineral resources and monitoring long-period eventssuch as Earth tides. Recently, researchers found several other intriguing features that we could even detect largeteleseismic earthquakes and monitor seismic ambient noise using gravimeters. The zero-length spring suspensiontechnology gives the gPhone (Micro-g LaCoste) excellent low frequency sensitivity, which may have implications forinvestigating much longer-period natural events (e.g., Earth’s hum, tsunami waves, etc.). In this study, we presentpreliminary results through temporary operation of the gPhone at Geumsan in South Korea for 9 months (Nov. 2008-Jul. 2009). The gPhone successfully recorded large teleseismic events and showed a clear seasonal variation of the Doublefrequency microseisms during its operation period.