lhosuna,

Pseudostatic and reduction of effective stress through pore water pressures (liquefaction) are the most common approaches.

You may want to get hold of the following papers to tailor/check your analyses:

Makdisi & Seed "Simplified Procedure for Estimating Dam and Embankment Earthquake-Induced Deformations."

Makdisi & Seed "A Simplified Procedure for Computing Maximum Crest Acceleration and Natural Period for Embankments."

Newmark "Earthquake-Resistant Design of Earth- and Rock-Fill Dams" (1965 Rankine Lecture)

Jeyapalan, Duncan & Seed "Analyses of Flow Failures of Mine Tailings Dams"

Hynes-Griffin & Franklin "Rationalizing the Seismic Coefficient Method" (USACOE Misc. Paper GL-84-13)

-Jeff

Ihosuna,

Also take a look at Chapter 10 in Soil Strength and Slope Stabiity by J.M. Duncan and S. G. Wright.  

Thanks for your help guys! It is my understanding that when performing a seismic slope stability analysis via Newmark the purpose is to calculate the permanent deformation for the slope in case instead of a factor of safety as in the pseudostatic analysis. However, once this deformation is calculated, what do we compare it to? What is the allowable deformation criteria? Do you know any sources I should mention for this allowable deformation? Thanks!

The allowable deformation is whatever your client needs.  If there is an important structure near the top, the allowable deformation may be 2 cm or less.  If it's just a fill slope below a parking lot, maybe 2 m would be OK too, as long as the slope is stable after the earthquake (as determined using appropriate post-earthquake strength and pore-water pressures).

OK, maybe 2m would cause damage to cars.  Just don't let them park Mercedes or Jaguars close to the slope - only cheap cars.

If it's a dam, the question of tolerable deformation is more difficult because of issues about how much freeboard is left, whether there is potential for cracking that could allow failure by seepage, etc.

Regards,
DRG

dgillette - let 'em park the mercedes and jags - BMWs and Ferraris too.  I have no sympathy for those who have the money for such cars and would lose them - and they can afford to lose them more than us poor working folks driving the old klunkers!!  
  See Kramer's book on Earthquake Engineering, too.

Please, Big H.  "Klunker" is a term of opprobrium.  My cars are not klunkers; they are beaters.

Sorry dgillette - it should have been clunker.  You can stay with your beater, I'll stay with my clunker.  But thank god for all those who buy new cars so I can buy the used ones!! - actually, the latest car I've ever owned is a 1981 - wow, 26 years ago!  Luckily, we have project trucks.

But seriously folks, if the analysis predicts large deformations, check to be sure that there is no loss of strength with large deformations, e.g., peak strength vs remolded vs residual friction angle.

dgillette - good point!