OASES version 1.7 allows for specifying a continuous sound speed profile through a flag rather than specifying the negative of the actual value at the bottom of the layer in the shear speed field as in SAFARI (OASES still supports this form also). The flag specification is particularly useful when running through many values of sound speed at a certain depth, such as for matched field inversion for SVP.
The continuity of the SVP at the bottom of a layer is activated by the usual parameter line for the layer:
| D | cc | cs | [L] |
with cs =-999.999 as a flag, i.e. by setting the shear speed for the layer to -999.999. All OASES modules will then set the sound speed at the bottom of the layer equal to the speed specified for the top of the next layer below.
As an example, the following is the OAST file saffip3.dat corresponding to the SAFARI test case 3 with the SVP being continuous at 30 m depth:
SAFARI-FIP case 3 N C A D J 30 30 1 0 5 0 0 0 0 0 0 0 0 1500 -999.999 0 0 1 0 # SVP continuous at z = 30 m 30 1480 -1490 0 0 1 0 100 1600 400 0.2 0.5 1.8 0 120 1800 600 0.1 0.2 2.0 0 50 0.1 120 41 40 1350 1E8 -1 1 950 0 5 20 1 20 80 12 10 0 120 12 20 40 70 6