摘要 |
A seismic sensor node 1 comprising one or more seismic sensors (8,9) and an annular skirt (3) defining an annular axis. The annular skirt (3) has a cutting edge (10) which appears serrated when viewed at a right angle to the annular axis. The skirt (3) also has a series of ribs (15) and channels (11) which terminate at the cutting edge so that the cutting edge has an undulating shape when viewed parallel with the annular axis. The ribbed shape of the skirt (3) makes it particularly resistant to ellipsoid or modal oscillation, so that it can transmit seismic vibrations to the seismic sensor (s) with minimal distortion, attenuation or damping. |