design spectral response

huangyhg

design spectral response
does anyone know of a good source for determining spectral response values for alaska other than asce and ibc maps?  i am reviewing some calculations, and came across sd1 and sds values with resolution to the thousandths.  is there a source that provides this, or am i looking at someone's work who had a really good eye for interpolation?
there's a program out there that gives you ss and s1 by zip code, but not to that degree of accuracy.  there's a point at which the numbers don't even make sense to use, you know?  i'd say go to the nearest tenth.
strikengineer,
ss and s1 are in the maps, not sds and sd1.  when you take the 2/3 factor to get to sds and sd1, you could get too many sig figs.
you might get more sigs figs from the nehrp program, i can't re  
i think ucfse has it explained.  it's sort of like this:
2 + 2 = 4.00000000