First order Discontinuities may be named for later association with specific effects. This property gives the format its name.
IMPORTANT: TTBOX needs the core mantle boundary and the inner core boundary being defined. Without defining these discontinuities, MKX4P and MKTIM4P will crash sooner or later, since CMB and ICB depths are used to restrict ray parameter ranges.
The following example shows the definition of a Moho within a PREM-like model:
0.000 5.80000 3.20000 2.60000 1451.91656 600.00000 15.000 5.80000 3.20000 2.60000 1451.91656 600.00000 15.000 5.80000 3.20000 2.60000 1451.91656 600.00000 24.400 6.80000 3.90000 2.90000 1345.91217 600.00000 mantle 24.4 8.11062 4.49100 3.38075 1441.7098 600 40.000 8.10097 4.48526 3.37905 1441.96734 600.00000 60.000 8.08861 4.47789 3.37688 1442.29855 600.00000
Values of physical parameters are defined above and below the discontinuity at the same depth (24.4km in the above example). The insertion of the predefined name causes MKREADND to store the depth of the Moho in the .moho-field of the model-structure.
PREM defines a Low velocity zone, which does not exist in all earth models. The beginning of this zone may be indicated by a non-predefined discontinuity name:
80.000 8.07625 4.47052 3.37471 1442.63089 600.00000 115.000 8.05461 4.45762 3.37090 195.43033 80.00000 150.000 8.03298 4.44472 3.36710 195.51154 80.00000 185.000 8.01134 4.43182 3.36329 195.59324 80.00000 220.000 7.98971 4.41892 3.35949 195.67543 80.00000 LVZ 220 8.55895 4.6439 3.43578 362.6702 143 265.000 8.64552 4.67540 3.46265 365.06069 143.00000
This Name and the associated depth (220 km) are stored in the .dz- and .dname-fields of the model-structure.