Block VI: Receivers

The specification of the receiver depths is slightly different than for OAST, with two records instead of one. The significance of the parameters is

RD1

Depth of uppermost source/receiver in vertical field matching arrays in meters.

RD2

Depth of lowermost source/receiver in vertical field matching arrays in meters.

NR

Number of source/receiver depths.

D1

Depth of uppermost receiver for which integrands and/or TL plots should be generated . Will be modified to closest depth in receiver array specified by RD1, RD2, and NR.

D2

Depth of lowermost receiver for which integrands and/or TL plots should be generated. Will be modified to closest depth in receiver array specified by RD1, RD2, and NR.

ND

Number of equidistant depths for which integrands and/or TL will be plotted.

By default, the NR and ND receivers are placed equidistantly in the vertical. Note that the vertical source/receiver arrays provide the only mechaanism for the field to propagate. Therefore, RD1 and RD2 must be chosen carefully. E.g. RD2 must be deep enough into the lower halfspace to include all significant upward radiating field. NR must be large enough to sample the vertical field distribution, i.e. denser than half the shortest vertical wavelength.

Non-equidistant Receiver Depths

In RDOASES the source/receiver depths can optionally be specified individually. The parameter NR is used as a flag for this option. Thus, if NR < 0the number of receivers is interpreted as -NR, with the individual depths following immidiately following Block VI.