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move and permanently displace during the period of acceleration when the yield acceleration is exceeded. The Newmark Method uses the ratio between the yield acceleration and the average peak horizontal ground acceleration (Ky/Kp) to de- termine the expected amount of permanent displacement. The Newmark graph shown on Figure 5 (see Appendix B) was used for the seis- mic stability evaluation. This graph was developed by Dr. Robert Pyke, Consult- ing Engineer, Berkeley, California, based on previous work by Franklin and Chang (1977) and Makdisi and Seed (1977). The chart shows the relationships between the acceleration ratio and estimated displacements for Richter magni- tude earthquakes (M) of 6.5 to 7.7 and 8 or greater. Table 2 (see Appendix B) also summarizes the results of the seismic slope sta- bility analyses. Yield accelerations for the excavation slope, refuse moving face, and final grading were 0.40g, 0.23g, and 0.45g, respectively, resulting in negligi- ble estimated permanent displacement during an MPE design earthquake. The slope stability report's conclusions and recommendations are presented be- low. • Because the ground -water table at the proposed site is deep, 125 to 150 feet below ground surface, and the foundation soils are medium dense to dense, the potential for liquefaction of the foun- dation soils is considered highly unlikely. • The stability analyses of the interim refuse slope with 3:1 slopes at a maximum height of 90 feet indicate that calculated safety factors are 1.6 to 2.1 under static conditions. The stability analyses of the final grading Isopes with maximum slopes of 12 percent indicate that calculated safety factors are 3.9 to 6.3 under static conditions. • Yield accelerations of 0.158 to 0.458 are calculated for MPE seis- mic loading resulting in negligible permanent displacement of the landfill slopes. The permanent drainage facilities within the landfill will have the capacity to carry peak flow from a 100 -year recurrence storm. Storm runoff volumes were calcu- PJ9 9390218A.00W 42 Rev. 0 July 20, 1989