Find seismic class for Soils - NW Indiana Find seismic class for Soils - NW Indiana amedhi (Geotechnical) (OP) 17 Dec 10 19:04 How do you search for seismic class for a property location in NW Indiana based on lab classification, and field N values ( N, SWV, G values ) or without much field data ? RE: Find seismic class for Soils - NW Indiana msucog (Civil/Environmental) 19 Dec 10 22:33 with N values, it's a very straightforward calculation as long as you accurately consider all variables and caveats in the IBC/ASCE7 methodology. it's almost identical with shear wave velocity except shear wave velocity should be a better approximation than N values. if you have N values and shear wave velocity, i'd say you have a fair amount of data as long as it goes 100 feet or at least to bedrock. search threads on this website...it has been discussed many times and i've posted tons of educational links. just remember to consider other aspects than simply averaging N values (many geotechs don't understand the most basic concepts and can't defend the way they calculate this so researching the topic will benefit both you and your client as well as other professionals).