According to the SPT based method you may have to define some more parameters. In the following section we briefly describe these methods.
Deterministic Seed (2004)
The available choices for the rd calculation are:
1. from mean curve: From the response results of combinations of site conditions and ground motions Seed calculated a mean rd value. This is the value used.
2. for specific Vs: Based on observations and the results of parametric studies, an equation for the calculation of rd was developed. This equation requires estimation of the site stiffness factor Vs for the upper 12 meters of soil strata.
3, 4. for site stiffness factor: Examination of the response of several sites to different ground motions resulted to two groups of rd graphs. The Vs range selected is used for the calculation of rd taking also into consideration the moment magnitude, the depth of the test point and the peak ground acceleration.
Probabilistic Seed (2004)
In addition to the previous mentioned options for the calculation of rd, when the probabilistic method of Seed (2004) is selected, you are prompt to enter the minimum probability for a test point to be characterized as liquefiable.
Probabilistic Liao et al. (1998)
For the probabilistic model you must choose the regression parameters used by the authors of the method according to the soil type. If you are unsure about the classification of your soil profile you can select the first option All cases.