Based on the concept that torsion balances act as good filters for rotational oscillations at frequencies above their natural frequency of oscillations, we have fabricated a simple prototype to serve as a rotational seismometer for near-field and engineering studies. This instrument displays a nearly flat response at frequencies above 10 mHz, and the preliminary data taken with this instrument show a sensitivity of 5 × 10-6(ν/0:01 Hz) rad sec-1 Hz-1/2. Marginal improvements of the fabrication and housing will be needed to fully cover the sensitivities recommended by a U.S. Geological Survey (USGS) panel for studies at these frequencies.
All Science Journal Classification (ASJC) codes
- Geochemistry and Petrology