Guralp Systems CMG-6T - Manual (Page 19)

Operator's Guide
Finally, many pit installations have a large space
around the seismometer, covered with a wooden
roof. Large air-filled cavities are susceptible to
currents which produce lower-frequency
vibrations, and sharp edges and corners can give
rise to turbulence. We recommend that a
wooden box is placed around the sensor to
protect it from these currents. Once in the box,
the emplacement may be backfilled with fresh
turf to insulate it from vibrations at the surface,
or simply roofed as before.
July 2011 19