| 摘要 |
A sensing means comprises four uniaxial sensors 1',2',3',4' each capable of detecting a movement component along a respective axis having a respective orientation and arranged such that the angles between any two of said respective orientations of said axes are substantially equal (to 109.471{), wherein the uniaxial sensors are arranged such that in use the respective axes are at substantially the same angle (54.7{) to the vertical. The arrangement allows determination of vibration components in three orthogonal directions. The sensors may be in a tetrahedral configuration (fig 2) or arranged along a common axis (fig 6). The sensors 1',2',3',4' may be geophones, seismometers or accelerometers and the arrangement may be used in a borehole, in a land based seismic survey or in an ocean bottom cable (OBC). |
