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{{#Wiki_filter:5. Hazard for the Control Point 5.1 SWUS Reference Rock Hazard Curves PG&E Letter DCL-15-154 Enclosure Page 37 of 50 Hazard curves for the SWUS reference rock condition were interpolated to finer sampling in frequency so that the site resonances can be captured. The interpolated hazard curves are listed in Table 8-1 in Appendix B. 5.2 Weights for the Empirical and Analytical Approaches The two approaches for estimating the site terms are applied using a logic tree approach. The technical justification for selecting the logic tree weights for the empirical and analytical approaches is given in this section. 5.2.1 Empirical Approach Strengths and Weaknesses A key advantage of the empirical approach is that the recorded ground motions at DCPP include the actual site effects; however, the event-corrected residuals may still contain some source and path effects in addition to the site effects. The corrected residuals in Figure 4-2 show that at high frequencies, the residuals are consistent between the three recordings, indicating that the mean residual is a robust estimate of a repeatable site effect. In contrast, at low frequencies (2.5 Hz and below), there is much larger scatter between the residuals for the three recordings, indicating that low-frequency event-corrected residuals may still contain path effects: the procedure to remove the region-specific distance scaling may not fully capture the path effects. An alternative interpretation of the larger scatter at low frequencies is that there are strong 3-D site response effects which depend on the azimuth and incidence angle of the input ground motion. A key limitation of the empirical approach is that the mean site term is based on only three recordings from two earthquakes. This limitation is directly addressed through the SE of the empirical site term. 5.2.2 Analytical Approach Strengths and Weaknesses A key advantage of the analytical approach is that it can represent the average site term over a large number of earthquake scenarios. The extensive site data at DCPP provides a well constrained velocity model down to depths of 3000 m. With such a deep velocity profile, the analytical site response modeling can capture both high -frequency and low-frequency site effects. The QWL amplification (Figure 2-5) shows that the site-specific amplification at low frequencies is similar, on average, to the amplification from a generic reference rock site representative of the SWUS ground motion model.
{{#Wiki_filter:5. Hazard for the Control Point 5.1 SWUS Reference Rock Hazard Curves PG&E Letter DCL-15-154 Enclosure Page 37 of 50 Hazard curves for the SWUS reference rock condition were interpolated to finer sampling in frequency so that the site resonances can be captured. The interpolated hazard curves are listed in Table 8-1 in Appendix B. 5.2 Weights for the Empirical and Analytical Approaches The two approaches for estimating the site terms are applied using a logic tree approach. The technical justification for selecting the logic tree weights for the empirical and analytical approaches is given in this section. 5.2.1 Empirical Approach Strengths and Weaknesses A key advantage of the empirical approach is that the recorded ground motions at DCPP include the actual site effects; however, the event-corrected residuals may still contain some source and path effects in addition to the site effects. The corrected residuals in Figure 4-2 show that at high frequencies, the residuals are consistent between the three recordings, indicating that the mean residual is a robust estimate of a repeatable site effect. In contrast, at low frequencies (2.5 Hz and below), there is much larger scatter between the residuals for the three recordings, indicating that low-frequency event-corrected residuals may still contain path effects: the procedure to remove the region-specific distance scaling may not fully capture the path effects. An alternative interpretation of the larger scatter at low frequencies is that there are strong 3-D site response effects which depend on the azimuth and incidence angle of the input ground motion. A key limitation of the empirical approach is that the mean site term is based on only three recordings from two earthquakes. This limitation is directly addressed through the SE of the empirical site term. 5.2.2 Analytical Approach Strengths and Weaknesses A key advantage of the analytical approach is that it can represent the average site term over a large number of earthquake scenarios. The extensive site data at DCPP provides a well constrained velocity model down to depths of 3000 m. With such a deep velocity profile, the analytical site response modeling can capture both high -frequency and low-frequency site effects. The QWL amplification (Figure 2-5) shows that the site-specific amplification at low frequencies is similar, on average, to the amplification from a generic reference rock site representative of the SWUS ground motion model.
PG&E Letter DCL-15-154 Enclosure Page 38 of 50 The analytical approach also allows for the consideration of nonlinear site effects that cannot be addressed by the weak motion available for the empirical approach; however, the available site-specific laboratory data is limited to studies from the 1970s. The results from the available lab studies (Figures 3-4 and 3-5) show a wide range of material properties from linear to significantly nonlinear. An important limitation of the analytical approach is that it is based on 1-D layered models of the site, but the 3-D velocity model developed by Fugro (Reference 4) shows that there are strong lateral heterogeneities in the velocity structure so that the 3-D site response may differ from the 1-D site response. 5.2.3 Selected Weights A common approach to evaluating weights for models is to consider the relative sizes of uncertainties of the alternative models. In this case, the epistemic uncertainty in the site terms using the analytical approach and the empirical approach are similar (about 0.25 LN units) for frequencies greater than 5 Hz. At low frequencies, the analytical modeling has much smaller uncertainty due to the use of a single deep velocity profile (below 125m). Based only on the epistemic uncertainties, the two approaches would be given equal weight at the high frequencies and the analytical approach would be given higher weight for the low frequencies. In our judgment, in general, data at a site is preferred over results from models because the empirical data capture more complex effects that are not considered in site response models such as 3-D effects. While the empirical method is based on only three recordings, the residuals are consistent for frequencies greater than 3 Hz. Therefore, we favor the empirical approach over the analytical approach in the frequency range. In the low-frequency range, the empirical site terms (Figure 4-2) show that, on average, there is amplification in the 1.5 to 2.5 Hz range. This site resonance, relative to a reference rock site, is not seen in the analytical results. Given the larger scatter in the corrected residuals in the frequency band, some of the 2 Hz amplification seen in the empirical site terms may actually be path effects rather than site effects; however, there may also be low-frequency 3-D SA that is not captured in the 1-D site response analysis, but is captured in the empirical factors, but with more variability than in the frequency range. The key -frequency range for safety-related systems, structures, and components at DCPP are above 3 Hz for which the empirical approach is well constrained. Given that the empirical site factors represent the actual linear SA, the residuals are consistent at high frequencies, and the rock properties are not highly nonlinear, we judge that the empirical approach should be favored over the analytical approach. Therefore, the weights favoring the empirical approach (weight = 2/3) over the analytical approach (weight = 1/3) are selected for the entire frequency range.
PG&E Letter DCL-15-154 Enclosure Page 38 of 50 The analytical approach also allows for the consideration of nonlinear site effects that cannot be addressed by the weak motion available for the empirical approach; however, the available site-specific laboratory data is limited to studies from the 1970s. The results from the available lab studies (Figures 3-4 and 3-5) show a wide range of material properties from linear to significantly nonlinear. An important limitation of the analytical approach is that it is based on 1-D layered models of the site, but the 3-D velocity model developed by Fugro (Reference 4) shows that there are strong lateral heterogeneities in the velocity structure so that the 3-D site response may differ from the 1-D site response. 5.2.3 Selected Weights A common approach to evaluating weights for models is to consider the relative sizes of uncertainties of the alternative models. In this case, the epistemic uncertainty in the site terms using the analytical approach and the empirical approach are similar (about 0.25 LN units) for frequencies greater than 5 Hz. At low frequencies, the analytical modeling has much smaller uncertainty due to the use of a single deep velocity profile (below 125m). Based only on the epistemic uncertainties, the two approaches would be given equal weight at the high frequencies and the analytical approach would be given higher weight for the low frequencies. In our judgment, in general, data at a site is preferred over results from models because the empirical data capture more complex effects that are not considered in site response models such as 3-D effects. While the empirical method is based on only three recordings, the residuals are consistent for frequencies greater than 3 Hz. Therefore, we favor the empirical approach over the analytical approach in the frequency range. In the low-frequency range, the empirical site terms (Figure 4-2) show that, on average, there is amplification in the 1.5 to 2.5 Hz range. This site resonance, relative to a reference rock site, is not seen in the analytical results. Given the larger scatter in the corrected residuals in the frequency band, some of the 2 Hz amplification seen in the empirical site terms may actually be path effects rather than site effects; however, there may also be low-frequency 3-D SA that is not captured in the 1-D site response analysis, but is captured in the empirical factors, but with more variability than in the frequency range. The key -frequency range for safety-related systems, structures, and components at DCPP are above 3 Hz for which the empirical approach is well constrained. Given that the empirical site factors represent the actual linear SA, the residuals are consistent at high frequencies, and the rock properties are not highly nonlinear, we judge that the empirical approach should be favored over the analytical approach. Therefore, the weights favoring the empirical approach (weight = 2/3) over the analytical approach (weight = 1/3) are selected for the entire frequency range.
5.2.4 Sensitivity PG&E Letter DCL-15-154 Enclosure Page 39 of 50 The sensitivity of the 1 E-4 and 1 E-5 uniform hazard spectra (UHS) to the approach used for the SA is shown in Figure 5-1. The main differences are at 1 0 Hz and 2 Hz: the analytical approach shows a site resonance near 10 Hz which is not seen in the residuals; the empirical approach shows a site resonance near 2 Hz that is not seen in the analytical results. .-C) *-<( -(..) Q) 0.. (/) 1 1 UHS (AnaJytJcal) -.. 1 E-5 UHS (Analytical) 1 E*4 UHS (Empirical) 1 E .. s UHS (Empirical) 0.1 1 10 100 requency (Hz) Figure 5 Sensitivity of the UHS to the Site Term Approach (From Reference 9)
5.2.4 Sensitivity PG&E Letter DCL-15-154 Enclosure Page 39 of 50 The sensitivity of the 1 E-4 and 1 E-5 uniform hazard spectra (UHS) to the approach used for the SA is shown in Figure 5-1. The main differences are at 1 0 Hz and 2 Hz: the analytical approach shows a site resonance near 10 Hz which is not seen in the residuals; the empirical approach shows a site resonance near 2 Hz that is not seen in the analytical results. .-C) *-<( -(..) Q) 0.. (/) 1 1 UHS (AnaJytJcal) -.. 1 E-5 UHS (Analytical) 1 E*4 UHS (Empirical) 1 E .. s UHS (Empirical) 0.1 1 10 100 requency (Hz) Figure 5-1 -Sensitivity of the UHS to the Site Term Approach (From Reference 9)
PG&E Letter DC L -15-154 Enclosure Page 40 of 50 5.3 Application of Analytical Site Amplification Factors to the Reference Ground Motion Models The GMPEs, on which the reference rock hazard is based, include nonlinearity in the site terms and standard deviation, but only based on the nonlinearity at the median ground motion level. The trend of the nonlinearity (slope of the log amplification as a function of the log SA) at the median ground motion level is assumed to apply to higher ground motion levels. Due to this assumption, tor the empirical GMPEs, the site term is close to linear at VS30=760 m/s for all epsilon values. In contrast, the analytical SA was computed relative to a reference rock site condition with VS30=760 m/s, a generic VS profile based on California rock sites, a kappa of 0.03 sec, and the Peninsula Range nonlinear properties. The analytical modeling will have different levels of nonlinearity as the ground motion level increases from the median level (epsilon= 0) to above median levels (epsilon > 0). So the nonlinearity for the_ reference rock condition in the analytical model, which is consistent with the expected physical behavior of the soil, is inconsistent with the nonlinearity in the GMPEs for VS30=760 m/s that was used to compute the hazard. That is, the computed hazard for the SWUS reference rock condition does not capture nonlinear behavior for ground motion levels above the median. To correct for this inconsistency, a set of SA factors between a linear VS30=760 and a nonlinear VS30=760 site condition were also computed. Figure 5-2 is a schematic illustration of this process. The simulated ground motion for the reference rock condition of 760_NL case is called SA0(f). The simulated ground motion for the control point is called SA1 (f) and depends on the amplitude of the reference rock ground motion. If the hazard had been computed for the 760_NL, it would be straightforward to compute the soil hazard, but because the hazard was run with a linear 760 GMPE, a correction to account for the limitation of the lack of nonlinearity in the GMPEs used for the hazard calculation is needed. Two amplifications are given from the analytical modeling: the amplification of the DCPP soil relative to the 760_NL case (called Amp1) and the amplification of the 760_LIN case relative to the 760_NL case (called Amp2). The desired amplification of the DCPP soil relative to the 760_LIN case (called Amp3) is given by the ratio of these two amplifications. Am (f SA (f))= SAt (f, SAo (f)) 'Pt ' o SAo (f) Am (f SA (f)) = SA2 (f,SA0 (f)) 'P2 ' o SAo (f)
PG&E Letter DC L 154 Enclosure Page 40 of 50 5.3 Application of Analytical Site Amplification Factors to the Reference Ground Motion Models The GMPEs, on which the reference rock hazard is based, include nonlinearity in the site terms and standard deviation, but only based on the nonlinearity at the median ground motion level. The trend of the nonlinearity (slope of the log amplification as a function of the log SA) at the median ground motion level is assumed to apply to higher ground motion levels. Due to this assumption, tor the empirical GMPEs, the site term is close to linear at VS30=760 m/s for all epsilon values. In contrast, the analytical SA was computed relative to a reference rock site condition with VS30=760 m/s, a generic VS profile based on California rock sites, a kappa of 0.03 sec, and the Peninsula Range nonlinear properties. The analytical modeling will have different levels of nonlinearity as the ground motion level increases from the median level (epsilon= 0) to above median levels (epsilon > 0). So the nonlinearity for the_ reference rock condition in the analytical model, which is consistent with the expected physical behavior of the soil, is inconsistent with the nonlinearity in the GMPEs for VS30=760 m/s that was used to compute the hazard. That is, the computed hazard for the SWUS reference rock condition does not capture nonlinear behavior for ground motion levels above the median. To correct for this inconsistency, a set of SA factors between a linear VS30=760 and a nonlinear VS30=760 site condition were also computed. Figure 5-2 is a schematic illustration of this process. The simulated ground motion for the reference rock condition of 760_NL case is called SA0(f). The simulated ground motion for the control point is called SA1 (f) and depends on the amplitude of the reference rock ground motion. If the hazard had been computed for the 760_NL, it would be straightforward to compute the soil hazard, but because the hazard was run with a linear 760 GMPE, a correction to account for the limitation of the lack of nonlinearity in the GMPEs used for the hazard calculation is needed. Two amplifications are given from the analytical modeling: the amplification of the DCPP soil relative to the 760_NL case (called Amp1) and the amplification of the 760_LIN case relative to the 760_NL case (called Amp2). The desired amplification of the DCPP soil relative to the 760_LIN case (called Amp3) is given by the ratio of these two amplifications. Am (f SA (f))= SAt (f, SAo (f)) 'Pt ' o SAo (f) Am (f SA (f)) = SA2 (f,SA0 (f)) 'P2 ' o SAo (f)
PG&E Letter DCL-15-154 Enclosure Page 41 of 50 Amp3 gives the amplification from the linear 760 case to the site-specific case, but it is a function of the ground motion level for the non-linear 760 case (SA0). The hazard calculation gives the rate of ground motions as a function of the ground motion for the 760 linear case (SA2). Therefore, the reference rock ground motion is changed from SAo to SA2: With these two relations, the amplification is relative to the reference rock condition used in the hazard calculation. The soil hazard can then be computed as described in Section 5.3.
PG&E Letter DCL-15-154 Enclosure Page 41 of 50 Amp3 gives the amplification from the linear 760 case to the site-specific case, but it is a function of the ground motion level for the non-linear 760 case (SA0). The hazard calculation gives the rate of ground motions as a function of the ground motion for the 760 linear case (SA2). Therefore, the reference rock ground motion is changed from SAo to SA2: With these two relations, the amplification is relative to the reference rock condition used in the hazard calculation. The soil hazard can then be computed as described in Section 5.3.
SA0(f)
SA0(f)
* M7, Depth:S k PG&E Letter DCL-15-154 Enclosure Page 42 of 50 Epice* tral distance set to give desire!i PGA1 Figure 5 Notation used to Compute the Site Amplification 5.4 Methodology for Applying Approach 3 The hazard for the reference site condition is computed using the global model and the single-station sigma. The site-specific hazard is computed using Approach 3, which 1\ requires estimating the site-specific Amp(f,PSAREF) term and the epistemic uncertainty 1\ 1\ in the Amp(f,PSAREF). The Amp(f,PSAREF) term is an average site term and does not include aleatory variability of the SA that may arise from different input ground motions. Because the single-station sigma only removed the effects of the average SA from the ergodic standard deviation, the aleatory variability of the SA is still part of the station sigma. The standard deviation for GMPEs is computed from ground motions that are mainly in the linear range, so the single-station sigma represents the aleatory SA in the linear range. If there is increased variability for highly nonlinear cases, then PG&E Letter DCL-15-154 Enclosure Page 43 of 50 that additional aleatory variability is not captured in the single-station sigma model. This additional aleatory variability at high ground motion levels is to be included in the soil hazard calculation. The hazard on soil is given by: f -dHaz(z REF) ( " ) Haz(PSAsoil > z,f) = p PSAsoil > z I dzREF dzREF where Haz(ZREF) is the hazard for the SA2(f) corresponding to the hazard for the SWUS reference rock condition, * ( " ) _ (In( z) -In( z REF Amp( z REF, f))) P PSAsoif > Z I Amp(zREF,f),&#xa2;amp_NL (zREF,f) <I>l j tPamp_NL (zREF,f) and <I>(x) is the standard normal cumulative distribution. As described in section 5.2, the amplification used in the soil hazard calculation is Amp3. The hazard integral is solved numerically. N . Haz(PSAsoil > z,f) = Lrate( zREFiJ)P( PSAsoit > z I Amp3(zREFi,f),&#xa2;a"&#xa5;'_NL (zREFi,f)) i=l where and z +z REFJ+1 ZREF; = 2 The rate(zREF;,f)is the rate of occurrence of reference rock ground motion level zREF; computed from the hazard curves, and the aleatory term, tPamp_NL(zREF,f), is given by the increase in the variance of the computed SA due to nonlinear effects. The PG&E Letter DCL-15-154 Enclosure Page 44 of 50 increase in the variance is computed by subtracting the variance from 0.1 g input motion, which is taken to represent the linear range. The aleatory term used in the soil hazard is given by: _ ( = O.lg,f) > = O.lg,f) &#xa2;amp NL (zREF,f)--0 = O.lg,f) where is the standard deviation of the SA due to the randomization of the soil properties. If the aleatory variability at high ground motion levels is smaller than at low ground motion levels, then the aleatory term is zero. 5.5 Soil Hazard Curves The soil hazard is computed using the methodology described in Section 5.4, which is consistent with Approach 3. The soil hazard curves are shown in Figure 5-3.
* M7, Depth:S k PG&E Letter DCL-15-154 Enclosure Page 42 of 50 Epice* tral distance set to give desire!i PGA1 Figure 5-2 -Notation used to Compute the Site Amplification 5.4 Methodology for Applying Approach 3 The hazard for the reference site condition is computed using the global model and the single-station sigma. The site-specific hazard is computed using Approach 3, which 1\ requires estimating the site-specific Amp(f,PSAREF) term and the epistemic uncertainty 1\ 1\ in the Amp(f,PSAREF). The Amp(f,PSAREF) term is an average site term and does not include aleatory variability of the SA that may arise from different input ground motions. Because the single-station sigma only removed the effects of the average SA from the ergodic standard deviation, the aleatory variability of the SA is still part of the station sigma. The standard deviation for GMPEs is computed from ground motions that are mainly in the linear range, so the single-station sigma represents the aleatory SA in the linear range. If there is increased variability for highly nonlinear cases, then PG&E Letter DCL-15-154 Enclosure Page 43 of 50 that additional aleatory variability is not captured in the single-station sigma model. This additional aleatory variability at high ground motion levels is to be included in the soil hazard calculation. The hazard on soil is given by: f -dHaz(z REF) ( " ) Haz(PSAsoil > z,f) = p PSAsoil > z I dzREF dzREF where Haz(ZREF) is the hazard for the SA2(f) corresponding to the hazard for the SWUS reference rock condition, * ( " ) _ (In( z) -In( z REF Amp( z REF, f))) P PSAsoif > Z I Amp(zREF,f),&#xa2;amp_NL (zREF,f) <I>l j tPamp_NL (zREF,f) and <I>(x) is the standard normal cumulative distribution. As described in section 5.2, the amplification used in the soil hazard calculation is Amp3. The hazard integral is solved numerically. N . Haz(PSAsoil > z,f) = Lrate( zREFiJ)P( PSAsoit > z I Amp3(zREFi,f),&#xa2;a"&#xa5;'_NL (zREFi,f)) i=l where and z +z REFJ+1 ZREF; = 2 The rate(zREF;,f)is the rate of occurrence of reference rock ground motion level zREF; computed from the hazard curves, and the aleatory term, tPamp_NL(zREF,f), is given by the increase in the variance of the computed SA due to nonlinear effects. The PG&E Letter DCL-15-154 Enclosure Page 44 of 50 increase in the variance is computed by subtracting the variance from 0.1 g input motion, which is taken to represent the linear range. The aleatory term used in the soil hazard is given by: _ ( = O.lg,f) > = O.lg,f) &#xa2;amp NL (zREF,f)--0 = O.lg,f) where is the standard deviation of the SA due to the randomization of the soil properties. If the aleatory variability at high ground motion levels is smaller than at low ground motion levels, then the aleatory term is zero. 5.5 Soil Hazard Curves The soil hazard is computed using the methodology described in Section 5.4, which is consistent with Approach 3. The soil hazard curves are shown in Figure 5-3.
0.000{)1 25Hz 10Hz 5Hz PG&E Letter DCL-15-154 Enclosure Page 45 of 50 2.sHz ! l 1 Hz l-f _ i I 0.5 Hz l r I i I i Ill 0.000001 0.01 0.1 1 Spect al Ace (g) Figure 5 Soil Hazard Curves for the Control Point (From Reference 9) 10 PG&E Letter DC L -15-154 Enclosure Page 46 of 50 6. Uniform Hazard Spectra and Ground Motion Response Spectrum The resulting UHS at 1 E-4 and 1 E-5 and the GMRS are listed in Table 6-1 and are plotted in Figure 6-1. Frequency (Hz) 100 so 39.84 33.33 25.13 20 16.58 13.33 11.75 10 8.32 6.67 5.89 5 4.47 4 3.71 3.33 2.82 2.5 2.24 2 1.66 1.33 1.17 1 0.79 0.67 0.58 0.5 0.4 0.33 Table 6 GMRS for the Control Point (From Reference 9) UHS 1E-4 UHS 1E-5 (g) (g) 0.856 1.621 0.878 1.665 0.902 1.720 0.912 1.737 0.994 1.905 1.088 2.075 1.217 2.322 1.437 2.718 1.489 2.822 1.509 2.863 1.583 3.002 1.723 3.277 1.762 3.368 1.850 3.528 1.817 3.511 1.842 3.562 1.755 3.401 1.701 3.305 1.825 3.652 1.913 3.899 1.816 3.697 1.716 3.460 1.507 3.154 1.283 2.753 1.074 2.299 0.859 1.844 0.626 1.398 0.499 1.122 0.410 0.928 0.337 0.773 0.243 0.549 0.195 0.434 GMRS (g) 0.856 0.879 0.907 0.916 1.004 1.094 1.224 1.437 1.490 1.511 1.585 1.729 1.775 1.861 1.847 1.873 1.788 1.736 1.907 2.029 1.924 1.804 1.633 1.418 1.185 0.950 0.714 0.572 0.473 0.393 0.280 0.222   
0.000{)1 25Hz 10Hz 5Hz PG&E Letter DCL-15-154 Enclosure Page 45 of 50 2.sHz ! l 1 Hz l-f _ i I 0.5 Hz l r I i I i Ill 0.000001 0.01 0.1 1 Spect al Ace (g) Figure 5-3 -Soil Hazard Curves for the Control Point (From Reference 9) 10 PG&E Letter DC L 154 Enclosure Page 46 of 50 6. Uniform Hazard Spectra and Ground Motion Response Spectrum The resulting UHS at 1 E-4 and 1 E-5 and the GMRS are listed in Table 6-1 and are plotted in Figure 6-1. Frequency (Hz) 100 so 39.84 33.33 25.13 20 16.58 13.33 11.75 10 8.32 6.67 5.89 5 4.47 4 3.71 3.33 2.82 2.5 2.24 2 1.66 1.33 1.17 1 0.79 0.67 0.58 0.5 0.4 0.33 Table 6-1 -GMRS for the Control Point (From Reference 9) UHS 1E-4 UHS 1E-5 (g) (g) 0.856 1.621 0.878 1.665 0.902 1.720 0.912 1.737 0.994 1.905 1.088 2.075 1.217 2.322 1.437 2.718 1.489 2.822 1.509 2.863 1.583 3.002 1.723 3.277 1.762 3.368 1.850 3.528 1.817 3.511 1.842 3.562 1.755 3.401 1.701 3.305 1.825 3.652 1.913 3.899 1.816 3.697 1.716 3.460 1.507 3.154 1.283 2.753 1.074 2.299 0.859 1.844 0.626 1.398 0.499 1.122 0.410 0.928 0.337 0.773 0.243 0.549 0.195 0.434 GMRS (g) 0.856 0.879 0.907 0.916 1.004 1.094 1.224 1.437 1.490 1.511 1.585 1.729 1.775 1.861 1.847 1.873 1.788 1.736 1.907 2.029 1.924 1.804 1.633 1.418 1.185 0.950 0.714 0.572 0.473 0.393 0.280 0.222   
--en -(.) u * * *
--en -(.) u * * *
* 1 E-4 UHS for Control Point 1 E-5 UHS for Control Point GMRS PG&E Letter DCL-15-154 Enclosure Page 47 of 50 <( '1 .... u Q) 0.. C/) :t 1 10 Freq ency (Hz) Figure 6 UHS for the Control Point and the GMRS (From Reference 9) 100   
* 1 E-4 UHS for Control Point 1 E-5 UHS for Control Point GMRS PG&E Letter DCL-15-154 Enclosure Page 47 of 50 <( '1 .... u Q) 0.. C/) :t 1 10 Freq ency (Hz) Figure 6-1 -UHS for the Control Point and the GMRS (From Reference 9) 100   
: 7. Conclusions PG&E Letter DCL-15-154 Enclosure Page 48 of 50 The approach to the development of the GMRS given in this RAI response differs from the approach used in the DCPP SHSR (Reference 3) in two key aspects: (1) the control point was changed from the a single location (ESTA28) to average site condition over the plant region, and (2) both the empirical and analytical approaches were used, rather than just the empirical approach. The GMRS given in Table 6-1 replaces the GMRS given in the DCPP SHSR (Reference 3). This GMRS represents PG&E's final GMRS for the response to Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident. Note that the GMRS given in Table 6-1 is for the average site condition over the plant region and will be used for screening purposes. An interim assessment of the updated GMRS described above is consistent with the conclusions of the screening and interim evaluations performed by PG&E and reported to the NRC in the SHSR (Reference 3). DCPP continues to screen "in" for additional risk evaluation (i.e., the performance of an updated/enhanced Seismic Probabilistic Risk Assessment) and there is reasonable assurance that DCPP remains safe to operate without undue risk to the public while an updated risk evaluation is being performed. The updated GMRS given in Table 6-1 remains bounded by the Long Term Seismic Program Margin Spectrum.   
: 7. Conclusions PG&E Letter DCL-15-154 Enclosure Page 48 of 50 The approach to the development of the GMRS given in this RAI response differs from the approach used in the DCPP SHSR (Reference 3) in two key aspects: (1) the control point was changed from the a single location (ESTA28) to average site condition over the plant region, and (2) both the empirical and analytical approaches were used, rather than just the empirical approach. The GMRS given in Table 6-1 replaces the GMRS given in the DCPP SHSR (Reference 3). This GMRS represents PG&E's final GMRS for the response to Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident. Note that the GMRS given in Table 6-1 is for the average site condition over the plant region and will be used for screening purposes. An interim assessment of the updated GMRS described above is consistent with the conclusions of the screening and interim evaluations performed by PG&E and reported to the NRC in the SHSR (Reference 3). DCPP continues to screen "in" for additional risk evaluation (i.e., the performance of an updated/enhanced Seismic Probabilistic Risk Assessment) and there is reasonable assurance that DCPP remains safe to operate without undue risk to the public while an updated risk evaluation is being performed. The updated GMRS given in Table 6-1 remains bounded by the Long Term Seismic Program Margin Spectrum.   
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Revision as of 22:51, 20 May 2018

Diablo Canyon, Units 1 and 2 - Response to NRC Request for Additional Information Dated October 1, 2015, and November 13, 2015, Regarding Recommendation 2.1 of the Near-Term Task Force Seismic Hazard and Screening Report
ML15355A551
Person / Time
Site: Diablo Canyon  Pacific Gas & Electric icon.png
Issue date: 12/21/2015
From: Strickland L J
Pacific Gas & Electric Co
To:
Office of Nuclear Reactor Regulation
Shared Package
ML15362A569 List:
References
DCL-15-154, TAC MF5275, TAC MF5276
Download: ML15355A551 (38)
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5. Hazard for the Control Point 5.1 SWUS Reference Rock Hazard Curves PG&E Letter DCL-15-154 Enclosure Page 37 of 50 Hazard curves for the SWUS reference rock condition were interpolated to finer sampling in frequency so that the site resonances can be captured. The interpolated hazard curves are listed in Table 8-1 in Appendix B. 5.2 Weights for the Empirical and Analytical Approaches The two approaches for estimating the site terms are applied using a logic tree approach. The technical justification for selecting the logic tree weights for the empirical and analytical approaches is given in this section. 5.2.1 Empirical Approach Strengths and Weaknesses A key advantage of the empirical approach is that the recorded ground motions at DCPP include the actual site effects; however, the event-corrected residuals may still contain some source and path effects in addition to the site effects. The corrected residuals in Figure 4-2 show that at high frequencies, the residuals are consistent between the three recordings, indicating that the mean residual is a robust estimate of a repeatable site effect. In contrast, at low frequencies (2.5 Hz and below), there is much larger scatter between the residuals for the three recordings, indicating that low-frequency event-corrected residuals may still contain path effects: the procedure to remove the region-specific distance scaling may not fully capture the path effects. An alternative interpretation of the larger scatter at low frequencies is that there are strong 3-D site response effects which depend on the azimuth and incidence angle of the input ground motion. A key limitation of the empirical approach is that the mean site term is based on only three recordings from two earthquakes. This limitation is directly addressed through the SE of the empirical site term. 5.2.2 Analytical Approach Strengths and Weaknesses A key advantage of the analytical approach is that it can represent the average site term over a large number of earthquake scenarios. The extensive site data at DCPP provides a well constrained velocity model down to depths of 3000 m. With such a deep velocity profile, the analytical site response modeling can capture both high -frequency and low-frequency site effects. The QWL amplification (Figure 2-5) shows that the site-specific amplification at low frequencies is similar, on average, to the amplification from a generic reference rock site representative of the SWUS ground motion model.

PG&E Letter DCL-15-154 Enclosure Page 38 of 50 The analytical approach also allows for the consideration of nonlinear site effects that cannot be addressed by the weak motion available for the empirical approach; however, the available site-specific laboratory data is limited to studies from the 1970s. The results from the available lab studies (Figures 3-4 and 3-5) show a wide range of material properties from linear to significantly nonlinear. An important limitation of the analytical approach is that it is based on 1-D layered models of the site, but the 3-D velocity model developed by Fugro (Reference 4) shows that there are strong lateral heterogeneities in the velocity structure so that the 3-D site response may differ from the 1-D site response. 5.2.3 Selected Weights A common approach to evaluating weights for models is to consider the relative sizes of uncertainties of the alternative models. In this case, the epistemic uncertainty in the site terms using the analytical approach and the empirical approach are similar (about 0.25 LN units) for frequencies greater than 5 Hz. At low frequencies, the analytical modeling has much smaller uncertainty due to the use of a single deep velocity profile (below 125m). Based only on the epistemic uncertainties, the two approaches would be given equal weight at the high frequencies and the analytical approach would be given higher weight for the low frequencies. In our judgment, in general, data at a site is preferred over results from models because the empirical data capture more complex effects that are not considered in site response models such as 3-D effects. While the empirical method is based on only three recordings, the residuals are consistent for frequencies greater than 3 Hz. Therefore, we favor the empirical approach over the analytical approach in the frequency range. In the low-frequency range, the empirical site terms (Figure 4-2) show that, on average, there is amplification in the 1.5 to 2.5 Hz range. This site resonance, relative to a reference rock site, is not seen in the analytical results. Given the larger scatter in the corrected residuals in the frequency band, some of the 2 Hz amplification seen in the empirical site terms may actually be path effects rather than site effects; however, there may also be low-frequency 3-D SA that is not captured in the 1-D site response analysis, but is captured in the empirical factors, but with more variability than in the frequency range. The key -frequency range for safety-related systems, structures, and components at DCPP are above 3 Hz for which the empirical approach is well constrained. Given that the empirical site factors represent the actual linear SA, the residuals are consistent at high frequencies, and the rock properties are not highly nonlinear, we judge that the empirical approach should be favored over the analytical approach. Therefore, the weights favoring the empirical approach (weight = 2/3) over the analytical approach (weight = 1/3) are selected for the entire frequency range.

5.2.4 Sensitivity PG&E Letter DCL-15-154 Enclosure Page 39 of 50 The sensitivity of the 1 E-4 and 1 E-5 uniform hazard spectra (UHS) to the approach used for the SA is shown in Figure 5-1. The main differences are at 1 0 Hz and 2 Hz: the analytical approach shows a site resonance near 10 Hz which is not seen in the residuals; the empirical approach shows a site resonance near 2 Hz that is not seen in the analytical results. .-C) *-<( -(..) Q) 0.. (/) 1 1 UHS (AnaJytJcal) -.. 1 E-5 UHS (Analytical) 1 E*4 UHS (Empirical) 1 E .. s UHS (Empirical) 0.1 1 10 100 requency (Hz) Figure 5-1 -Sensitivity of the UHS to the Site Term Approach (From Reference 9)

PG&E Letter DC L 154 Enclosure Page 40 of 50 5.3 Application of Analytical Site Amplification Factors to the Reference Ground Motion Models The GMPEs, on which the reference rock hazard is based, include nonlinearity in the site terms and standard deviation, but only based on the nonlinearity at the median ground motion level. The trend of the nonlinearity (slope of the log amplification as a function of the log SA) at the median ground motion level is assumed to apply to higher ground motion levels. Due to this assumption, tor the empirical GMPEs, the site term is close to linear at VS30=760 m/s for all epsilon values. In contrast, the analytical SA was computed relative to a reference rock site condition with VS30=760 m/s, a generic VS profile based on California rock sites, a kappa of 0.03 sec, and the Peninsula Range nonlinear properties. The analytical modeling will have different levels of nonlinearity as the ground motion level increases from the median level (epsilon= 0) to above median levels (epsilon > 0). So the nonlinearity for the_ reference rock condition in the analytical model, which is consistent with the expected physical behavior of the soil, is inconsistent with the nonlinearity in the GMPEs for VS30=760 m/s that was used to compute the hazard. That is, the computed hazard for the SWUS reference rock condition does not capture nonlinear behavior for ground motion levels above the median. To correct for this inconsistency, a set of SA factors between a linear VS30=760 and a nonlinear VS30=760 site condition were also computed. Figure 5-2 is a schematic illustration of this process. The simulated ground motion for the reference rock condition of 760_NL case is called SA0(f). The simulated ground motion for the control point is called SA1 (f) and depends on the amplitude of the reference rock ground motion. If the hazard had been computed for the 760_NL, it would be straightforward to compute the soil hazard, but because the hazard was run with a linear 760 GMPE, a correction to account for the limitation of the lack of nonlinearity in the GMPEs used for the hazard calculation is needed. Two amplifications are given from the analytical modeling: the amplification of the DCPP soil relative to the 760_NL case (called Amp1) and the amplification of the 760_LIN case relative to the 760_NL case (called Amp2). The desired amplification of the DCPP soil relative to the 760_LIN case (called Amp3) is given by the ratio of these two amplifications. Am (f SA (f))= SAt (f, SAo (f)) 'Pt ' o SAo (f) Am (f SA (f)) = SA2 (f,SA0 (f)) 'P2 ' o SAo (f)

PG&E Letter DCL-15-154 Enclosure Page 41 of 50 Amp3 gives the amplification from the linear 760 case to the site-specific case, but it is a function of the ground motion level for the non-linear 760 case (SA0). The hazard calculation gives the rate of ground motions as a function of the ground motion for the 760 linear case (SA2). Therefore, the reference rock ground motion is changed from SAo to SA2: With these two relations, the amplification is relative to the reference rock condition used in the hazard calculation. The soil hazard can then be computed as described in Section 5.3.

SA0(f)

  • M7, Depth:S k PG&E Letter DCL-15-154 Enclosure Page 42 of 50 Epice* tral distance set to give desire!i PGA1 Figure 5-2 -Notation used to Compute the Site Amplification 5.4 Methodology for Applying Approach 3 The hazard for the reference site condition is computed using the global model and the single-station sigma. The site-specific hazard is computed using Approach 3, which 1\ requires estimating the site-specific Amp(f,PSAREF) term and the epistemic uncertainty 1\ 1\ in the Amp(f,PSAREF). The Amp(f,PSAREF) term is an average site term and does not include aleatory variability of the SA that may arise from different input ground motions. Because the single-station sigma only removed the effects of the average SA from the ergodic standard deviation, the aleatory variability of the SA is still part of the station sigma. The standard deviation for GMPEs is computed from ground motions that are mainly in the linear range, so the single-station sigma represents the aleatory SA in the linear range. If there is increased variability for highly nonlinear cases, then PG&E Letter DCL-15-154 Enclosure Page 43 of 50 that additional aleatory variability is not captured in the single-station sigma model. This additional aleatory variability at high ground motion levels is to be included in the soil hazard calculation. The hazard on soil is given by: f -dHaz(z REF) ( " ) Haz(PSAsoil > z,f) = p PSAsoil > z I dzREF dzREF where Haz(ZREF) is the hazard for the SA2(f) corresponding to the hazard for the SWUS reference rock condition, * ( " ) _ (In( z) -In( z REF Amp( z REF, f))) P PSAsoif > Z I Amp(zREF,f),¢amp_NL (zREF,f) l j tPamp_NL (zREF,f) and (x) is the standard normal cumulative distribution. As described in section 5.2, the amplification used in the soil hazard calculation is Amp3. The hazard integral is solved numerically. N . Haz(PSAsoil > z,f) = Lrate( zREFiJ)P( PSAsoit > z I Amp3(zREFi,f),¢a"¥'_NL (zREFi,f)) i=l where and z +z REFJ+1 ZREF; = 2 The rate(zREF;,f)is the rate of occurrence of reference rock ground motion level zREF; computed from the hazard curves, and the aleatory term, tPamp_NL(zREF,f), is given by the increase in the variance of the computed SA due to nonlinear effects. The PG&E Letter DCL-15-154 Enclosure Page 44 of 50 increase in the variance is computed by subtracting the variance from 0.1 g input motion, which is taken to represent the linear range. The aleatory term used in the soil hazard is given by: _ ( = O.lg,f) > = O.lg,f) ¢amp NL (zREF,f)--0 = O.lg,f) where is the standard deviation of the SA due to the randomization of the soil properties. If the aleatory variability at high ground motion levels is smaller than at low ground motion levels, then the aleatory term is zero. 5.5 Soil Hazard Curves The soil hazard is computed using the methodology described in Section 5.4, which is consistent with Approach 3. The soil hazard curves are shown in Figure 5-3.

0.000{)1 25Hz 10Hz 5Hz PG&E Letter DCL-15-154 Enclosure Page 45 of 50 2.sHz ! l 1 Hz l-f _ i I 0.5 Hz l r I i I i Ill 0.000001 0.01 0.1 1 Spect al Ace (g) Figure 5-3 -Soil Hazard Curves for the Control Point (From Reference 9) 10 PG&E Letter DC L 154 Enclosure Page 46 of 50 6. Uniform Hazard Spectra and Ground Motion Response Spectrum The resulting UHS at 1 E-4 and 1 E-5 and the GMRS are listed in Table 6-1 and are plotted in Figure 6-1. Frequency (Hz) 100 so 39.84 33.33 25.13 20 16.58 13.33 11.75 10 8.32 6.67 5.89 5 4.47 4 3.71 3.33 2.82 2.5 2.24 2 1.66 1.33 1.17 1 0.79 0.67 0.58 0.5 0.4 0.33 Table 6-1 -GMRS for the Control Point (From Reference 9) UHS 1E-4 UHS 1E-5 (g) (g) 0.856 1.621 0.878 1.665 0.902 1.720 0.912 1.737 0.994 1.905 1.088 2.075 1.217 2.322 1.437 2.718 1.489 2.822 1.509 2.863 1.583 3.002 1.723 3.277 1.762 3.368 1.850 3.528 1.817 3.511 1.842 3.562 1.755 3.401 1.701 3.305 1.825 3.652 1.913 3.899 1.816 3.697 1.716 3.460 1.507 3.154 1.283 2.753 1.074 2.299 0.859 1.844 0.626 1.398 0.499 1.122 0.410 0.928 0.337 0.773 0.243 0.549 0.195 0.434 GMRS (g) 0.856 0.879 0.907 0.916 1.004 1.094 1.224 1.437 1.490 1.511 1.585 1.729 1.775 1.861 1.847 1.873 1.788 1.736 1.907 2.029 1.924 1.804 1.633 1.418 1.185 0.950 0.714 0.572 0.473 0.393 0.280 0.222

--en -(.) u * * *

  • 1 E-4 UHS for Control Point 1 E-5 UHS for Control Point GMRS PG&E Letter DCL-15-154 Enclosure Page 47 of 50 <( '1 .... u Q) 0.. C/) :t 1 10 Freq ency (Hz) Figure 6-1 -UHS for the Control Point and the GMRS (From Reference 9) 100
7. Conclusions PG&E Letter DCL-15-154 Enclosure Page 48 of 50 The approach to the development of the GMRS given in this RAI response differs from the approach used in the DCPP SHSR (Reference 3) in two key aspects: (1) the control point was changed from the a single location (ESTA28) to average site condition over the plant region, and (2) both the empirical and analytical approaches were used, rather than just the empirical approach. The GMRS given in Table 6-1 replaces the GMRS given in the DCPP SHSR (Reference 3). This GMRS represents PG&E's final GMRS for the response to Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident. Note that the GMRS given in Table 6-1 is for the average site condition over the plant region and will be used for screening purposes. An interim assessment of the updated GMRS described above is consistent with the conclusions of the screening and interim evaluations performed by PG&E and reported to the NRC in the SHSR (Reference 3). DCPP continues to screen "in" for additional risk evaluation (i.e., the performance of an updated/enhanced Seismic Probabilistic Risk Assessment) and there is reasonable assurance that DCPP remains safe to operate without undue risk to the public while an updated risk evaluation is being performed. The updated GMRS given in Table 6-1 remains bounded by the Long Term Seismic Program Margin Spectrum.
8. References PG&E Letter DCL-15-154 Enclosure Page 49 of 50 1. Electric Power Research Institute, Report No. 1 025287, "Seismic Evaluation Guidance: Screening, Prioritization, and Implementation Details (SPID) for the Resolution of Fukushima Near-term Task Force Recommendation 2.1 -Seismic," February 2013 (NRC endorsement in ADAMS Accession No. ML 12333A 170) 2. Electric Power Research Institute, Report No. TR-1 02293, "Guidelines for Deterntining Design Basis Ground Motions," November 1993 3. PG&E Letter DCL-15-035, "Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding the Seismic Aspects of Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident: Seismic Hazard and Screening Report," dated March 11, 2015 (ADAMS Accession No. ML 15071A046) 4. Fugro, "Update of the Three-Dimensional Velocity Model for the Diablo Canyon Power Plant (DCPP) Foundation Area," May 2015 5. Fugro, "1-D Vp Profile below the DCPP Area," Memorandum from D. O'Connell, A. Fernandez, and T. Travasarou (Fugro) toN. Abrahamson (PG&E), dated December 14, 2015 6. GeoPentech, Technical Report-"Southwestern United States Ground Motion Characterization SSHAC Level 3," Revision 2, March 2015 7. Kamai, R., W. Silva, and N. Abrahamson, "Nonlinear Horizontal Site Response for the NGA-West2 Project," Pacific Earthquake Engineering Research Center Report No. 2013/12, May 2013 8. Pacific Engineering and Analysis, "Development of Amplification Factors for the Diablo Canyon Nuclear Power Plant: Site-Wide Profiles," Report to PG&E, dated November 24, 2015 9. PG&E (2015) Calculation No. GEO.DCPP.15.02, "Updated DCPP GMRS Using the Analytical and Empirical Site-Term Approaches," Revision 0 10.PG&E (2015), Calculation No. GEO.DCPP.15.03, "VS-kappa Scale Factors for DCPP using QWL and IRVT Method," Revision 0 11. Silva, W.J., N. Abrahamson, G. Toro, C. Costantino, Report No. 94PJ20 to the Brookhaven National Laboratory, Associated Universities, Inc. Upton, New York, "Description and Validation of the Stochastic Ground Motion Model," dated November 15, 1996 PG&E Letter DC L 154 Enclosure Page 50 of 50 12. Fugro, "Update of the Three-Dimensional Velocity Model for the Diablo Canyon Power Plant (DCPP) Foundation Area-Supplemental Report," November 2015 13. Lin, P.-S., Chiou, B., Abrahamson, N., Walling, M., Lee, C.-T., and Cheng, C.-T., Bulletin of the Seismological Society of America, Vol. 101 (5), 2281-2295, DOl: 10.1785/012009031, "Repeatable Source, Site, and Path Effects on the Standard Deviation for Empirical Ground-Motion Prediction Models," October 2011 14. PG&E Letter DCL-88-192, "Long Term Seismic Program Completion," dated July 31, 1988, with enclosure "Long Term Seismic Program Final Report" 15. Bechtel Power Corporation, "Final Report on the Diablo Canyon Long Term Seismic Program Soil Structure Interaction Analysis," July 1988 Appendix A PG&E Letter DCL-15-154 Enclosure Appendix A Page 1 of 22 A 1. Velocity Profile, Density, and Scale-Factor Tables Table A-1 -Host Velocity Profile and Density (From Reference 8) Layer Thickness vs (m) (m/s) 1.524 477.18 1.219 520.04 2.286 583.38 2.286 643 3.353 704.81 4.572 771.49 5.486 858.16 6.705 944.84 7.62 1030.18 10.057 1133.8 12.801 1264.86 10.667 1377.63 10.668 1377.63 10.159 1456.87 10.16 1456.87 10.16 1456.87 14.223 1484.31 14.223 1484.31 14.224 1484.31 100 1530 115 1720 160 1890 237 2070 228 2300 550 2550 800 2760 1100 2970 1550 3150 2400 3320 6100 3500 Density (gm/cmA3) 1.8 1.9 1.9 1.9 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.17 2.23 2.28 2.33 2.4 2.47 2.53 2.59 2.64 2.69 2.75 Layer Thickness (m) 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 PG&E Letter DCL-15-154 Enclosure Appendix A Page 2 of 22 Table A-2-Target Velocity Profile and Density (From Reference 8) Central Profile Lower Profile Upper Profile vs Density vs Density vs Density (m/s) (gm/cmA3) (m/s) (gm/cmA3) (m/s) (gm/cmA3) 640.5 1.92 505.2 1.92 812.2 2.1 657.7 1.92 519.3 1.92 832.9 2.1 675.7 1.92 534.7 1.92 853.8 2.1 688.3 1.92 541.2 1.92 875.3 2.1 707.8 2.1 559.3 1.92 895.6 2.1 724.4 2.1 572.8 1.92 916 2.1 733.7 2.1 573.9 1.92 938 2.1 742.5 2.1 573.5 1.92 961.3 2.1 749.1 2.1 568.7 1.92 986.8 2.1 759 2.1 569 1.92 1012.4 2.1 777.2 2.1 583.1 1.92 1035.9 2.1 785.7 2.1 582.4 1.92 1060 2.1 794.7 2.1 582.4 1.92 1084.5 2.1 804.4 2.1 584 1.92 1108.2 2.1 815.1 2.1 586.6 1.92 1132.6 2.1 827.1 2.1 591.1 1.92 1157.4 2.1 842.8 2.1 602.1 1.92 1179.9 2.1 863.5 2.1 621.5 1.92 1199.9 2.1 887 2.1 646.1 1.92 1217.8 2.1 910.6 2.1 672.1 1.92 1233.7 2.1 938.1 2.1 705.6 2.1 1247.3 2.1 965.5 2.1 739 2.1 1261.4 2.1 984.8 2.1 758.8 2.1 1278.2 2.1 998.2 2.1 768.8 2.1 1296 2.1 1010.3 2.1 777 2.1 1313.7 2.1 1022.9 2.1 786.4 2.1 1330.6 2.1 1036 2.1 797.6 2.1 1345.7 2.1 1050.1 2.1 812.4 2.1 1357.3 2.1 1064.8 2.1 828.3 2.1 1368.8 2.1 1078.5 2.1 842.9 2.1 1379.9 2.1 1089.7 2.1 855.8 2.1 1387.5 2.1 1099.5 2.1 867.2 2.1 1394 2.1 1108.5 2.1 877.6 2.1 1400 2.1 1116.5 2.1 887.8 2.1 1404.3 2.1 1123.5 2.1 896.7 2.1 1407.5 2.1 1130.1 2.1 905.3 2.1 1410.6 2.1 1135.9 2.1 913.6 2.1 1412.3 2.1 Layer Thickness (m) 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 PG&E Letter DCL-15-154 Enclosure Appendix A Page 3 of 22 Table A-2. Target Velocity Profile and Density (continued) Central Profile Lower Profile Upper Profile vs Density vs Density vs Density (m/s) (gm/cmJ\3) (m/s) (gm/cmA3) (m/s) (gm/cmA3) 1140.5 2.1 920 2.1 1413.9 2.1 1145.5 2.1 926.9 2.1 1415.7 2.1 1151.4 2.1 935.5 2.1 1417 2.1 1158.1 2.1 946.5 2.1 1417.1 2.1 1163.7 2.1 955.6 2.1 1417.3 2.1 1168.5 2.1 963 2.1 1417.8 2.1 1172.7 2.1 969.6 2.1 1418.4 2.1 1175.6 2.1 974 2.1 1418.9 2.1 1175.8 2.1 974.1 2.1 1419.4 2.1 1176.2 2.1 974.3 2.1 1419.8 2.1 1177.8 2.1 975.8 2.1 1421.7 2.1 1181.5 2.1 979 2.1 1426 2.1 1185.8 2.1 982.8 2.1 1430.6 2.1 1191.1 2.1 987.5 2.1 1436.7 2.1 1195.9 2.1 991.2 2.1 1442.9 2.1 1199.1 2.1 991.5 2.1 1450.1 2.1 1202.3 2.1 991.5 2.1 1457.9 2.1 1205.5 2.1 990 2.1 1467.9 2.1 1208.2 2.1 987.1 2.1 1478.7 2.1 1211.9 2.1 985.8 2.1 1489.8 2.1 1216.3 2.1 984.6 2.1 1502.5 2.2 1220.8 2.1 984.1 2.1 1514.5 2.2 1225.8 2.1 984 2.1 1526.9 2.2 1231.2 2.1 984 2.1 1540.7 2.2 1236.4 2.1 982.9 2.1 1555.3 2.2 1240.9 2.1 980.6 2.1 1570.2 2.2 1245.9 2.1 979.8 2.1 1584.3 2.2 1250.5 2.1 978.1 2.1 1598.8 2.2 1255.3 2.1 976.9 2.1 1613.2 2.2 1259.2 2.1 975 2.1 1626.3 2.2 1262.7 2.1 973 2.1 1638.7 2.2 1266.1 2.1 970.8 2.1 1651.2 2.2 1267.6 2.1 967.7 2.1 1660.6 2.2 1268.7 2.1 964.3 2.1 1669.2 2.2 1269.7 2.1 960.9 2.1 1677.6 2.2 1269.2 2.1 957.2 2.1 1682.9 2.2 1268.5 2.1 953.5 2.1 1687.5 2.2 1267.7 2.1 949.9 2.1 1691.8 2.2 Layer Central Profile Thickness vs I Density (m) (m/s) (gm/cmA3) 0.51 1265.3 2.1 0.51 1262.7 2.1 0.5 1260.8 2.1 0.51 1258.9 2.1 0.51 1256.7 2.1 0.51 1255.2 2.1 0.51 1252.3 2.1 0.5 1249.3 2.1 0.51 1246.3 2.1 0.51 1242.3 2.1 0.51 1237.9 2.1 0.51 1233.5 2.1 0.5 1228.3 2.1 0.51 1222.6 2.1 0.51 1216.1 2.1 0.51 1207.9 2.1 0.51 1199.3 2.1 0.5 1190.3 2.1 0.51 1180.3 2.1 0.51 1170.5 2.1 0.51 1160.9 2.1 0.51 1151.4 2.1 0.5 1142.2 2.1 0.51 1133.4 2.1 0.51 1125.7 2.1 0.51 1117.8 2.1 0.51 1110 2.1 0.5 1103.5 2.1 0.51 1097.1 2.1 0.51 1091.6 2.1 0.51 1087.2 2.1 0.51 1082.9 2.1 0.5 1079.4 2.1 0.51 1077 2.1 0.51 1075.1 2.1 0.51 1074 2.1 0.51 1074.4 2.1 0.5 1074.3 2.1 0.51 1074.9 2.1 0.51 1076.8 2.1 Lower Profile vs Density (m/s) (gm/cmA3) 945.2 2.1 941.6 2.1 938.4 2.1 935.1 2.1 931.5 2.1 929.1 2.1 924.9 2.1 920.8 2.1 917.6 2.1 914.4 2.1 911 2.1 909 2.1 907.9 2.1 907 2.1 906.4 2.1 906.6 2.1 907.5 2.1 907.6 2.1 906.5 2.1 906.4 2.1 906.6 2.1 906.7 2.1 907 2.1 907.2 2.1 908.1 2.1 908.4 2.1 908.2 2.1 908.6 2.1 908.8 2.1 910.1 2.1 911.5 2.1 912.7 2.1 914.6 2.1 916.5 2.1 919.1 2.1 922.8 2.1 927.2 2.1 930.4 2.1 934.3 2.1 939 2.1 PG&E Letter DCL-15-154 Enclosure Appendix A Page 4 of 22 Upper Profile vs Density (m/s) (gm/cmA3) 1693.7 2.2 1693.5 2.2 1694.1 2.2 1694.7 2.2 1695.4 2.2 1695.7 2.2 1695.6 2.2 1694.9 2.2 1692.7 2.2 1687.8 2.2 1681.9 2.2 1673.8 2.2 1661.6 2.2 1647.9 2.2 1631.7 2.2 1609.4 2.2 1584.9 2.2 1561.1 2.2 1536.7 2.2 1511.5 2.2 1486.5 2.1 1462.2 2.1 1438.4 2.1 1416.1 2.1 1395.5 2.1 1375.5 2.1 1356.5 2.1 1340.1 2.1 1324.4 2.1 1309.3 2.1 1296.8 2.1 1284.8 2.1 1273.9 2.1 1265.7 2.1 1257.5 2.1 1250 2.1 1245.1 2.1 1240.5 2.1 1236.5 2.1 1234.8 2.1 Layer Central Profile Thickness vs [ Density (m) (m/s) (gm/cmA3) 0.51 1079.3 2.1 0.51 1083.4 2.1 0.5 1086.6 2.1 0.51 1089.3 2.1 0.51 1092.8 2.1 0.51 1096.2 2.1 0.51 1099.2 2.1 0.5 1103.2 2.1 0.51 1106.9 2.1 0.51 1111.2 2.1 0.51 1115.2 2.1 0.51 1119 2.1 0.5 1122.5 2.1 0.51 1125.4 2.1 0.51 1128.6 2.1 0.51 1131.9 2.1 0.51 1135.5 2.1 0.5 1138.9 2.1 0.51 1142.2 2.1 0.51 1146.5 2.1 0.51 1150 2.1 0.51 1153.4 2.1 0.5 1156.4 2.1 0.51 1159.8 2.1 0.51 1163.8 2.1 0.51 1167 2.1 0.51 1170.1 2.1 0.5 1172.7 2.1 0.51 1175.3 2.1 0.51 1178.6 2.1 0.51 1181.6 2.1 0.51 1183.8 2.1 0.5 1186.2 2:1 0.51 1188.7 2.1 0.51 1190.9 2.1 0.51 1192.6 2.1 0.51 1194.3 2.1 0.5 1196.1 2.1 0.51 1197.2 2.1 0.51 1198.2 2.1 Lower Profile vs Density (m/s) (gm/cmA3) 944.6 2.1 952 2.1 957.4 2.1 961.9 2.1 967.3 2.1 972.1 2.1 976.3 2.1 981 2.1 985.4 2.1 990.5 2.1 994.9 2.1 999.1 2.1 1002.6 2.1 1005.5 2.1 1008.5 2.1 1011.6 2.1 1014.9 2.1 1018.8 2.1 1022.2 2.1 1027.4 2.1 1031.4 2.1 1035.2 2.1 1038.5 2.1 1042.7 2.1 1047.5 2.1 1051.5 2.1 1055.3 2.1 1059.1 2.1 1063 2.1 1066.4 2.1 1069.2 2.1 1071.1 2.1 1073.3 2.1 1075.6 2.1 1077.6 2.1 1079.1 2.1 1080.7 2.1 1082.2 2.1 1083.3 2.1 1084.2 2.1 PG&E Letter DCL-15-154 Enclosure Appendix A Page 5 of 22 Upper Profile vs Density (m/s) (gm/cmA3) 1233.1 2.1 1232.9 2.1 1233.3 2.1 1233.6 2.1 1234.7 2.1 1236.1 2.1 1237.7 2.1 1240.6 2.1 1243.3 2.1 1246.5 2.1 1250.1 2.1 1253.4 2.1 1256.7 2.1 1259.5 2.1 1263.1 2.1 1266.5 2.1 1270.3 2.1 1273.2 2.1 1276.2 2.1 1279.3 2.1 1282.2 2.1 1285.2 2.1 1287.6 2.1 1290.2 2.1 1293 2.1 1295.3 2.1 1297.4 2.1 1298.5 2.1 1299.6 2.1 1302.5 2.1 1305.9 2.1 1308.3 2.1 1311 2.1 1313.7 2.1 1316.2 2.1 1318 2.1 1319.9 2.1 1321.8 2.1 1323.1 2.1 1324.3 2.1 Layer Central Profile Thickness vs I *Density (m) (m/s) (gm/cmA3) 0.51 1199.4 2.1 0.51 1200.3 2.1 0.5 1200.7. 2.1 0.51 1200.5 2.1 0.51 1200.4 2.1 0.51 1201.3 2.1 0.51 1202.2 2.1 0.5 1203.1 2.1 0.51 1204 2.1 0.51 1205.6 2.1 0.51 1205.9 2.1 0.51 1206.5 2.1 0.5 1207.4 2.1 0.51 1208 2.1 0.51 1209.3 2.1 0.51 1210.9 2.1 0.51 1212.6 2.1 0.5 1214.1 2.1 0.51 1216 2.1 0.51 1217.1 2.1 0.51 1218.5 2.1 0.51 1220.1 2.1 0.5 1221.8 2.1 0.51 1224.2 2.1 0.51 1226.1 2.1 0.51 1228.1 2.1 0.51 1230 2.1 0.5 1232.3 2.1 0.51 1233.4 2.1 0.51 1235.1 2.1 0.51 1237.4 2.1 0.51 1239.2 2.1 0.5 1240.4 2.1 0.51 1241.5 2.1 0.51 1242.7 2.1 0.51 1243.4 2.1 0.51 1245 2.1 0.5 1246.3 2.1 0.51 1248.3 2.1 0.51 1249.6 2.1 Lower Profile vs Density (m/s) (gm/cm/\3) 1085.3 2.1 1086.1 2.1 1086.4 2.1 1086.2 2.1 1086.2 2.1 1086.9 2.1 1087.8 2.1 1088.6 2.1 1089.4 2.1 1090.9 2.1 1091.2 2.1 1091.7 2.1 1092.5 2.1 1093 2.1 1094.3 2.1 1095.7 2.1 1097.2 2.1 1098.6 2.1 1100.3 2.1 1101.3 2.1 1102.5 2.1 1104 2.1 1105.5 2.1 1107.7 2.1 1109.5 2.1 1111.3 2.1 1113 2.1 1115 2.1 1116 2.1 1117.6 2.1 1119.6 2.1 1121.3 2.1 1122.4 2.1 1123.4 2.1 1124.4 2.1 1125.1 2.1 1126.5 2.1 1127.7 2.1 1129.5 2.1-1130.7 2.1 PG&E Letter DCL-15-154 Enclosure Appendix A Page 6 of 22 Upper Profile vs Density (m/s) (gm/cm/\3) 1325.6 2.1 1326.6 2.1 1327 2.1 1326.7 2.1 1326.7 2.1 1327.6 2.1 1328.7 2.1 1329.6 2.1 1330.6 2.1 1332.4 2.1 1332.7 2.1 1333.4 2.1 1334.4 2.1 1335 2.1 1336.5 2.1 1338.3 2.1 1340.1 2.1 1341.8 2.1 1343.9 2.1 1345.1 2.1 1346.6 2.1 1348.4 2.1 1350.3 2.1 1352.9 2.1 1355.1 2.1 1357.3 2.1 1359.4 2.1 1361.9 2.1 1363.1 . 2.1 1365 2.1 1367.5 2.1 1369.6 2.1 1370.9 2.1 1372.1 2.1 1373.4 2.1 1374.2 2.1 1375.9 2.1 1377.4 2.1 1379.6 2.1 1381.1 2.1 Layer Central Profile Thickness vs I Density (m) (m/s) (gm/cmA3) 0.51 1250.6 2.1 0.51 1251.8 2.1 0.5 1253.3 2.1 0.51 1254.6 2.1 0.51 1256.3 2.1 0.51 1258.1 2.1 0.51 1260.1 2.1 0.5 1262.1 2.1 0.51 1263.9 2.1 0.51 1266.2 2.1 0.51 1268.7 2.1 0.51 1271 2.1 0.5 1273.5 2.1 0.51 1276 2.1 0.51 1277.9 2.1 0.51 1278.8 2.1 0.51 1280.7 2.1 0.5 1281.9 2.1 0.51 1282.6 2.1 0.51 1283.6 2.1 0.51 1284.3 2.1 0.51 1284.8 2.1 0.5 1285.4 2.1 0.51 1286.5 2.1 0.51 1287.5 2.1 0.51 1288.6 2.1 0.51 1289.4 2.1 0.5 1289.5 2.1 0.51 1289.8 2.1 0.51 1290.3 2.1 0.51 1290.5 2.1 0.51 1290.6 2.1 0.5 1290.8 2.1 0.51 1290.1 2.1 0.51 1289.3 2.1 0.51 1288.9 2.1 0.51 1289.2 2.1 0.5 1289.7 2.1 0.51 1290 2.1 0.51 1290 2.1 Lower Profile vs Density (m/s) (gm/cmA3) 1131.6 2.1 1132.6 2.1 1134.1 2.1 1135.2 2.1 1136.8 2.1 1138.4 2.1 1140.2 2.1 1142 2.1 1143.7 2.1 1145.7 2.1 1148 2.1 1150.1 2.1 1152.3 2.1 1154.6 2.1 1156.3 2.1 1157.1 2.1 1158.8 2.1 1159.9 2.1 1160.5 2.1 1161.4 2.1 1162.1 2.1 1162.5 2.1 1163.1 2.1 1164.1 2.1 1165 2.1 1166 2.1 1166.7 2.1 1166.8 2.1 1167.1 2.1 1167.5 2.1 1167.7 2.1 1167.8 2.1 1167.9 2.1 1167.3 2.1 1166.6 2.1 1166.3 2.1 1166.6 2.1 1167 2.1 1167.3 2.1 1167.2 2.1 PG&E Letter DCL-15-154 Enclosure Appendix A Page 7 of 22 Upper Profile vs Density (m/s) (gm/cmA3) 1382.1 2.1 1383.4 2.1 1385.2 2.1 1386.5 2.1 1388.5 2.1 1390.4 2.1 1392.7 2.1 1394.8 2.1 1396.9 . 2.1 1399.3 2.1 1402.1 2.1 1404.7 2.1 1407.5 2.1 1410.2 2.1 1412.2 2.1 1413.3 2.1 1415.4 2.1 1416.7 2.1 1417.5 2.1 1418.6 2.1 1419.4 2.1 1419.9 2.1 1420.6 2.1 1421.8 2.1 1422.9 2.1 1424.1 2.1 1425 2.1 1425.2 2.1 1425.4 2.1 1426 2.1 1426.2 2.1 1426.4 2.1 1426.5 2.1 1425.8 2.1 1424.9 2.1 1424.5 2.1 1424.8 2.1 1425.3 2.1 1425.7 2.1 1425.7 2.1 Layer Central Profile Thickness vs I Density (m) (m/s) (gm/cmA3) 0.51 1290.1 2.1 0.51 1289.9 2.1 0.5 1289.8 2.1 0.51 1290.1 2.1 0.51 1290.4 2.1 0.51 1290.7 2.1 0.51 1291 2.1 0.5 1291.2 2.1 0.51 1291.6 2.1 0.51 1291.7 2.1 0.51 1291.6 2.1 0.51 1291.3 2.1 0.5 1292.4 2.1 15.03 1293 2.1 16.47 1320 2.1 30.48 1395 2.1 30.48 1497.6 2.1 30.48 1557.1 2.2 30.48 1682.6 2.2 30.48 1800.6 2.2 30.48 1881.3 2.2 30.48 1971.5 2.2 30.48 2011.3 2.2 30.48 2078.1 2.2 30.48 2078.1 2.2 30.48 2146.2 2.2 30.48 2146.2 2.2 30.48 2205.4 2.2 30.48 2205.4 2.2 30.48 2260.1 2.2 30.48 2260.1 2.2 30.48 2334.5 2.2 30.48 2334.5 2.2 30.48 2430.7 2.2 30.48 2430.7 2.2 30.48 2523.5 2.52 30.48 2523.5 2.52 30.48 2526.1 2.52 30.48 2526.1 2.52 30.48 2489.3 2.2 Lower Profile vs Density (m/s) (gm/cmA3) 1167.4 2.1 1167.1 2.1 1167.1 2.1 1167.3 2.1 1167.6 2.1 1167.8 2.1 1168.1 2.1 1168.3 2.1 1168.7 2.1 1168.8 2.1 1168.7 2.1 1168.4 2.1 1169.4 2.1 1170 2.1 1200 2.1 1262.3 2.1 1355.1 2.1 1408.9 2.1 1522.5 2.2 1629.3 2.2 1702.3 2.2 1783.9 2.2 1819.9 2.2 1880.3 2.2 1880.3 2.2 1942 2.2 1942 2.2 1995.5 2.2 1995.5 2.2 2045 2.2 2045 2.2 2112.3 2.2 2112.3 2.2 2199.4 2.2 2199.4 2.2 2283.4 2.2 2283.4 2.2 2285.7 2.2 2285.7 2.2 2252.4 2.2 PG&E Letter DCL-15-154 Enclosure Appendix A Page 8 of 22 Upper Profile vs Density (m/s) (gm/cmA3) 1425.8 2.1 1425.5 2.1 1425.5 2.1 1425.7 2.1 1426.1 2.1 1426.4 2.1 1426.8 2.1 1427 2.1 1427.4 2.1 1427.6 2.1 1427.4 2.1 1427.1 2.1 1428.4 2.1 1429 2.1 1460 2.1 1541.7 2.2 1655.1 2.2 1720.9 2.2 1859.6 2.2 1990 2.2 2079.2 2.2 2178.8 2.2 2222.8 2.2 2296.7 2.2 2296.7 2.2 2371.9 2.2 2371.9 2.2 2437.3 2.2 2437.3 2.2 2497.8 2.2 2497.8 2.2 2580 2.52 2580 2.52 2686.3 2.52 2686.3 2.52 2788.9 2.52 2788.9 2.52 2791.8 2.52 2791.8 2.52 2751.1 2.52 Layer Central Profile Thickness vs I Density (m) (m/s) (gm/cmA3) 30.48 2489.3 2.2 30.48 2467 2.2 30.48 2467 2.2 30.48 2467.5 2.2 30.48 2467.5 2.2 30.48 2487.6 2.2 30.48 2487.6 2.2 30.48 2521.1 2.52 30.48 2521.1 2.52 30.48 2563.1 2.52 30.48 2563.1 2.52 30.48 2611.5 2.52 30.48 2611.5 2.52 30.48 2662.3 2.52 30.48 2662.3 2.52 30.48 2712 2.52 30.48 2712 2.52 30.48 2756 2.52 30.48 2756 2.52 30.48 2791.8 2.52 30.48 2791.8 2.52 30.48 2815.8 2.52 30.48 2815.8 2.52 30.48 2826.4 2.52 30.48 2826.4 2.52 30.48 2842.6 2.52 30.48 2842.6 2.52 30.48 2860.8 2.52 30.48 2860.8 2.52 30.48 2882.4 2.52 30.48 2882.4 2.52 30.48 2904 2.52 30.48 2904 2.52 30.48 2924.3 2.52 30.48 2924.3 2.52 30.48 2946.7 2.52 30.48 2946.7 2.52 30.48 2966.8 2.52 30.48 2966.8 2.52 30.48 2987.5 2.52 Lower Profile vs Density (m/s) (gm/cmA3) 2252.4 2.2 2232.2 2.2 2232.2 2.2 2232.7 2.2 2232.7 2.2 2250.9 2.2 2250.9 2.2 2281.2 2.2 2281.2 2.2 2319.2 2.2 2319.2 2.2 2363 2.2 2363 2.2 2408.9 2.2 2408.9 2.2 2453.9 2.2 2453.9 2.2 2493.7 2.2 2493.7 2.2 2526.1 2.52 2526.1 2.52 2547.8 2.52 2547.8 2.52 2557.4 2.52 2557.4 2.52 2572.1 2.52 2572.1 2.52 2588.6 2.52 2588.6 2.52 2608.1 2.52 2608.1 2.52 2627.6 2.52 2627.6 2.52 2646 2.52 2646 2.52 2666.3 2.52 2666.3 2.52 2684.5 2.52 2684.5 2.52 2703.2 2.52 PG&E Letter DCL-15-154 Enclosure Appendix A Page 9 of 22 Upper Profile vs Density (m/s) (gm/cmA3) 2751.1 2.52 2726.5 2.52 2726.5 2.52 2727 2.52 2727 2.52 2749.2 2.52 2749.2 2.52 2786.2 2.52 2786.2 2.52 2832.7 2.52 2832.7 2.52 2886.2 2.52 2886.2 2.52 2942.3 2.52 2942.3 2.52 2997.2 2.52 2997.2 2.52 3045.9 2.52 3045.9 2.52 3085.4 2.52 3085.4 2.52 3111.9 2.52 3111.9 2.52 3123.7 2.52 3123.7 2.52 3141.6 2.52 3141.6 2.52 3161.7 2.52 3161.7 2.52 3185.5 2.52 3185.5 2.52 3209.4 2.52 3209.4 2.52 3231.9 2.52 3231.9 2.52 3256.6 2.52 3256.6 2.52 3278.8 2.52 3278.8 2.52 3301.7 2.52 Layer Central Profile Thickness vs I Density (m) (m/s) (gm/cmA3) 30.48 2987.5 2.52 30.48 3008 2.52 30.48 3008 2.52 30.48 3025.8 2.52 30.48 3025.8 2.52 30.48 3044.8 2.52 30.48 3044.8 2.52 30.48 3065.3 2.52 30.48 3065.3 2.52 30.48 3082.9 2.52 30.48 3082.9 2.52 30.48 3098.7 2.52 30.48 3098.7 2.52 30.48 3111.1 2.52 30.48 3111.1 2.52 30.48 3122.3 2.52 30.48 3122.3 2.52 30.48 3135.6 2.52 30.48 3135.6 2.52 30.48 3154 2.52 30.48 3154 2.52 30.48 3161 2.52 30.48 3161 2.52 1100 3161 2.52 1550 3161 2.52 2400 3320 2.69 110.281 3500 2.75 Lower Profile vs Density (m/s) (gm/cmA3) 2703.2 2.52 2721.8 2.52 2721.8 2.52 2737.9 2.52 2737.9 2.52 2755 2.52 2755 2.52 2773.6 2.52 2773.6 2.52 2789.5 2.52 2789.5 2.52 2803.8 2.52 2803.8 2.52 2815 2.52 2815 2.52 2825.2 2.52 2825.2 2.52 2837.2 2.52 2837.2 2.52 2853.9 2.52 2853.9 2.52 2860.2 2.52 2860.2 2.52 2970 2.59 3150 2.64 3320 2.69 3500 2.75 PG&E Letter DCL-15-154 Enclosure Appendix A Page 10 of 22 Upper Profile vs Density (m/s) (gm/cmA3) 3301.7 2.52 3324.4 2.52 3324.4 2.52 3344 2.52 3344 2.52 3365 2.52 3365 2.52 3387.7 2.52 3387.7 2.52 3407.1 2.52 3407.1 2.52 3424.6 2.52 3424.6 2.52 3438.3 2.52 3438.3 2.52 3450.7 2.52 3450.7 2.52 3465.4 2.52 3465.4 2.52 3485.7 2.52 3485.7 2.52 3493.4 2.52 3493.4 2.52 3500 2.75 3500 2.75 3500 2.75 3500 2.75 PG&E Letter DCL-15-154 Enclosure Appendix A Page 11 of 22 Table A-3-Scale Factors Used to Develop the Lower and Upper VS Profiles Layer Thickness Scale Factor for Scale Factor for (m) Lower Profile VS Upper Profile VS 0.51 0.789 1.268 0.51 0.790 1.266 0.5 0.791 1.264 0.51 0.786 1.272 0.51 0.790 1.265 0.51 0.791 1.264 0.51 0.782 1.278 0.5 0.772 1.295 0.51 0.759 1.317 0.51 0.750 1.334 0.51 0.750 1.333 0.51 0.741 1.349 0.5 0.733 1.365 0.51 0.726 1.378 0.51 0.720 1.390 0.51 0.715 1.399 0.51 0.714 1.400 0.5 0.720 1.390 0.51 0.728 1.373 0.51 0.738 1.355 0.51 0.752 1.330 0.51 0.765 1.306 0.5 0.771 1.298 0.51 0.770 1.298 0.51 0.769 1.300 0.51 0.769 1.301 0.51 0.770 1.299 0.5 0.774 1.293 0.51 0.778 1.285 0.51 0.782 1.279 0.51 0.785 1.273 0.51 0.789 1.268 0.5 0.792 1.263 0.51 0.795 1.258 0.51 0.798 1.253 0.51 0.801 1.248 Layer Thickness (m) 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 Scale Factor for Lower Profile VS 0.804 0.807 0.809 0.812 0.817 0.821 0.824 0.827 0.829 0.828 0.828 0.828 0.829 0.829 0.829 0.829 0.827 0.825 0.821 0.817 0.813 0.810 0.806 0.803 0.799 0.795 0.790 0.786 0.782 0.778 0.774 0.771 0.767 0.763 0.760 0.757 0.754 0.752 . PG&E Letter DCL-15-154 Enclosure Appendix A Page 12 of 22 Scale Factor for Upper Profile VS 1.243 1.240 1.236 1.231 1.224 1.218 1.213 1.210 1.207 1.207 1.207 1.207 1.207 1.206 1.206 1.207 1.209 1.213 1.218 1.224 1.229 1.235 1.241 1.246 1.251 1.258 1.265 1.272 1.279 1.285 1.292 1.298 1.304 1.310 1.316 1.321 1.326 1.330 Layer Thickness Scale Factor for (m) Lower Profile VS 0.51 0.749 0.51 0.747 0.51 0.746 0.5 0.744 0.51 0.743 0.51 0.741 0.51 0.740 0.51 0.739 0.5 0.737 . 0.51 0.736 0.51 0.736 0.51 0.736 0.51 0.737 0.5 0.739 0.51 0.742 0.51 0.745 0.51 0.751 0.51 0.757 0.5 0.762 0.51 0.768 0.51 0.774 0.51 0.781 0.51 0.787 0.5 0.794 0.51 0.800 0.51 0.807 0.51 0.813 0.51 0.818 0.5 0.823 0.51 0.828 0.51 0.834 0.51 0.838 0.51 0.843 0.5 0.847 0.51 0.851 0.51 0.855 0.51 0.859 0.51 0.863 PG&E Letter DCL-15-154 Enclosure Appendix A Page 13 of 22 Scale Factor for Upper Profile VS 1.335 1.339 1.341 1.344 1.346 1.349 1.351 1.354 1.357 1.358 1.359 1.359 1.357 1.353 1.348 1.342 1.332 1.322 1.312 1.302 1.291 1.280 1.270 1.259 1.249 1.240 1.231 1.222 1.214 1.207 1.199 1.193 1.186 1.180 1.175 1.170 1.164 1.159 Layer Thickness (m) 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 Scale Factor for Lower Profile VS 0.866 0.869 0.872 0.875 0.879 0.881 0.883 0.885 0.887 0.888 0.889 0.890 0.891 0.892 0.893 0.893 0.893 0.894 0.894 0.894 0.895 0.895 0.896 0.897 0.898 0.898 0.899 0.900 0.901 0.902 0.903 0.904 0.905 0.905 0.905 0.905 0.905 0.905 PG&E Letter DCL-15-154 Enclosure Appendix A Page 14 of 22 Scale Factor for Upper Profile VS 1.155 1.150 1.147 1.142 1.138 1.135 1.132 1.130 1.128 1.126 1.125 1.123 1.122 1.121 1.120 1.120 1.119 1.119 1.119 1.119 1.118 1.117 1.116 1.115 1.114 1.113 1.112 1.111 1.110 1.109 1.107 1.106 1.105 1.105 1.105 1.105 1.105 1.105 Layer Thickness (m) 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 Scale Factor for Lower Profile VS 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 PG&E Letter DCL-15-154 Enclosure Appendix A Page 15 of 22 Scale Factor for Upper Profile VS 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 Layer Thickness (m) 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 Scale Factor for Lower Profile VS 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 PG&E Letter DCL-15-154 Enclosure Appendix A Page 16 of 22 Scale Factor for Upper Profile VS 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 Layer Thickness (m) 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51 0.51 0.51 0.5 0.51 0.51' 0.51 0.51 0.5 15.03 16.47 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 Scale Factor for Lower Profile VS 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 \ 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.909 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 PG&E Letter DCL-15-154 Enclosure Appendix A Page 17 of 22 Scale Factor for Upper Profile VS 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.106 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 Layer Thickness (m) 30.48 30.48 30.48 30.48 30.48 30.48 30.48\ 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 Scale Factor for Lower Profile VS 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 PG&E Letter DCL-15-154 Enclosure Appendix A Page 18 of 22 Scale Factor for Upper Profile VS 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 Layer Thickness (m) 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 30.48 1100 1550 Scale Factor for Lower Profile VS 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905 0.905' 0.905 0.905 0.905 0.905 0.905 0.905 0.905 .0.905 0.940 0.997 PG&E Letter DCL-15-154 Enclosure Appendix A Page 19 of 22 Scale Factor for Upper Profile VS 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.105 1.107 1.107 Layer Thickness Scale Factor for (m) Lower Profile VS 2400 1.000 110.281 1.000 PG&E Letter DCL-15-154 Enclosure Appendix A Page 20 of 22 Scale Factor for Upper Profile VS 1.054 1.000 PG&E Letter OCL-15-154 Enclosure Appendix A Page 21 of 22 A2. Comparison of May 2015 and November 2015 Velocity Models The November 2015 supplemental report on the Fugro 3-0 velocity model (Reference 12) provides an update the May 2015 3-0 velocity model (Reference 4) in response to the peer review comments. Using the same selection of locations for the plant region (Figure 2-1 ), the November 2015 velocity profiles are plotted in Figure A-1 along with the central, upper, and lower profiles described in Section 2.2. At depths below 15m, the central profile is consistent with the geometric mean of the VS profiles from the November 2015 model. At shallower depths, the geometric mean from the November 2015 model leads to VS values that are 5 to 10 percent higher than for the central profile. The VS30 for the geometric mean for the November 2015 model is 1 006 m/s compared to 968 m/s for the central profile. This increase in VS would lead to a small decrease (about 1-2 percent) in the high-frequency GMRS from the change in the impedance contrast; however, it would also lead to slightly reduced nonlinearity of the amplification, which could increase the high-frequency GMRS slightly, as discussed below. To estimate the potential effect due to reduced nonlinearity, the mean amplification in the linear range can be compared to the mean amplification at the 1 E-4 hazard level. Figure 3-7 shows the analytical amplification in the linear range and Figure 3-8 shows the analytical amplification at the 1 E-4 hazard level, which control the GMRS for OCPP. Comparing the mean amplification for 0.2 g and 1.07 g shows that the nonlinearity leads to 5 to 10 percent reduction in the amplification at 10 Hz. Assuming that the logarithm of the change in nonlinear amplification is proportional to the logarithm of the change in the shallow velocity, then a 1 0 percent increase in the shallow VS would lead to about 1 percent increase in the nonlinear amplification at 10 Hz. Given that the linear model (M1) is given 0.5 weight in the logic tree and the analytical model is given 1/3 weight, the effect on the GMRS at high frequencies would be less than 1 percent. The change in the impedance contrast and the reduced nonlinearity have opposite effects on the high-frequency hazard. The combined effects of the reduced impedance contrast and the reduced nonlinearity is expected to lead to a small reduction (less than 1 percent) in the GMRS at high frequencies. The velocity model also affects the empirical site term due to VS30 scaling used to adjust the ground motions recorded at ESTA27 and ESTA28 to the control point VS30. A comparison of the VS30 values based on the May and November velocity models is given in Table A-4. For ESTA27, the VS30 values are very similar. For ESTA28, the November VS30 values are about 2.5 percent smaller than the May VS30 values. For the control point, the November VS30 values are 4 percent higher than the May values. With the small decrease in the VS30 for EST A28 and the small increase in the VS30 for the control point, there would be a small (less than 2 percent at any frequency)

PG&E Letter DCL-15-154 Enclosure Appendix A Page 22 of 22 decrease in the adjustment factor (from ESTA27 and ESTA28 to the control point), leading a small decrease in the GMRS compared to the values listed in Table 6-1. Therefore, the use of the May velocity model is conservative relative to the November velocity model for the development of the GMRS. Table A-4. VS30 Values Station May 2015 Nov. 2015 ESTA27 852 m/s 856 m/s ESTA28 797 m/s 777 m/s Control Point 968 m/s 1006 m/s Vs-Depth Plots (Nov. 2015) Vs (m/sec) 0 200 400 600 800 1000 1200 1400 1600 1800 60 I .J: 1l. Gl 0 80 -100 ----l----i-----+---f-----+------'4\i 120 -+------+------+----1-----f-------+----Figure A-1 -Comparison of the November 2015 Velocity Profiles for the Plant Region with the Selected Central, Upper, and Lower Velocity Profiles PSA (g) 0.01 0.05 0.1 0.2 0.4 0.8 1.5 2.0 3.0 5.0 10 Appendix B PG&E Letter DCL-15-154 Enclosure Appendix 8 Page 1 of 2 Hazard for the Reference Rock Site Condition Tables Table 8-1 -Interpolated Hazard for the Reference Rock Site Condition (T=0.01 sec. to T=0.085 sec.) (From Reference 9) T=0.01 T=0.02 T=0.025 T=0.03 T=0.040 T=0.05 T=0.060 T=0.075 T=0.085 2.21 E-01 2.24E-01 2.31 E-01 2.37E-01 2.52E-01 2.64E-01 2.80E-01 3.01 E-01 3.12E-01 3.31 E-02 3.38E-02 3.59E-02 3.76E-02 4.32E-02 4.82E-02 5.45E-02 6.28E-02 6.73E-02 1.28E-02 1.32E-02 1.42E-02 1.51 E-02 1.77E-02 2.01E-02 2.30E-02 2.68E-02 2.87E-02 4.50E-03 4.70E-03 5.12E-03 5.48E-03 6.55E-03 7.57E-03 8.86E-03 1.07E-02 1.14E-02 1.42E-03 1.53E-03 1.68E-03 1.82E-03 2.24E-03 2.64E-03 3.15E-03 3.86E-03 4.18E-03 2.72E-04 3.06E-04 3.55E-04 3.98E-04 5.51E-04 7.17E-04 9.04E-04 1.18E-03 1.32E-03 3.21 E-05 3.79E-05 4.65E-05 5.45E-05 8.79E-05 1.29E-04 1.78E-04 2.58E-04 3.02E-04 1.04E-05 1.25E-05 1.56E-05 1.86E-05. 3.18E-05 4.89E-05 6.98E-05 1.06E-04 1.27E-04 1.84E-06 2.27E-06 2.92E-06 3.57E-06 6.52E-06 1.06E-05 1.58E-05 2.51 E-05 3.12E-05 1.68E-07 2.13E-07 2.85E-07 3.59E-07 7.12E-07 1.24E-06 1.93E-06 3.23E-06 4.15E-06 4.30E-09 5.72E-09 8.10E-09 1.06E-08 2.38E-08 4.56E-08 7.52E-08 1.35E-07 1.82E-07 Table 8-1 (continued)-Interpolated Hazard for the Reference Rock Site Condition (T=0.10 sec. to T=0.30 sec.) PSA (g) T=0.1 T=0.12 T=0.15 T=0.17 T=0.2 T=0.22 T=0.25 T=0.27 T=0.3 0.01 3.27E-01 3.38E-01 3.50E-01 3.55E-01 3.62E-01 3.62E-01 3.62E-01 3.60E-01 3.57E-01 0.05 7.36E-02 7.81E-02 8.38E-02 8.41E-02 8.43E-02 8.18E-02 7.94E-02 7.66E-02 7.27E-02 0.1 3.13E-02 3.31E-02 3.53E-02 3.50E-02 3.46E-02 3.30E-02 3.15E-02 3.00E-02 2.78E-02 0.2 1.25E-02 1.32E-02 1.41E-02 1.38E-02 1.34E-02 1.25E-02 1.17E-02 1.10E-02 9.91E-03 0.4 4.62E-03 4.89E-03 5.25E-03 5.06E-03 4.83E-03 4.44E-03 4.09E-03 3.76E-03 3.32E-03 0.8 1.51 E-03 1.63E-03 1.79E-03 1.72E-03 1.63E-03 1.46E-03 1.32E-03 1.17E-03 9.87E-04 1.5 3.70E-04 4.21E-04 4.91 E-04 4.67E-04 4.38E-04 3.77E-04 3.25E-04 2.72E-04 2.11 E-04 2 1.61 E-04 1.88E-04 2.26E-04 2.14E-04 2.00E-04 1.68E-04 1.42E-04 1.16E-04 8.63E-05 3 4.11 E-05 4.95E-05 6.18E-05 5.83E-05 5.41 E-05 4.42E-05 3.63E-05 2.89E-05 2.07E-05 5 5.72E-06 7.09E-06 9.17E-06 8.64E-06 8.00E-06 6.34E-06 5.06E-06 3.93E-06 2.71E-06 10 2.67E-07 3.42E-07 4.60E-07 4.33E-07 4.01 E-07 3.06E-07 2.34E-07 1.77E-07 1.17E-07 PG&E Letter DCL-15-154 Enclosure Appendix 8 Page 2 of 2 Table 8-1 (continued)-Interpolated Hazard for the Reference Rock Site Condition (T=0.355 sec. to T=1.26 sec.) PSA (g) T=0.355 T=0.40 T=0.45 T=0.5 T=0.60 T=0.75 T=0.85 T=1.00 T=1.26 0.01 3.45E-01 3.36E-01 3.23E-01 3.10E-01 2.72E-01 2.33E-01 2.01E-01 1.66E-01 1.19E-01 0.05 6.42E-02 5.87E-02 5.26E-02 4.70E-02 3.64E-02 2.70E-02 2.14E-02 1.59E-02 1.04E-02 0.1 2.39E-02 2.15E-02 1.89E-02 1.66E-02 1.24E-02 8.85E-03 6.91 E-03 5.04E-03 3.19E-03 0.2 8.26E-03 7.26E-03 6.26E-03 5.38E-03 3.95E-03 2.75E-03 2.17E-03 1.60E-03 9.70E-04 0.4 2.69E-03 2.32E-03 1.99E-03 1.70E-03 1.22E-03 8.23E-04 6.30E-04 4.48E-04 2.41E-04 0.8 7.53E-04 6.21E-04 5.09E-04 4.16E-04 2.79E-04 1.75E-04 1.24E-04 8.00E-05 3.72E-05 1.5 1.51 E-04 1.19E-04 9.08E-05 6.89E-05 4.45E-05 2.67E-05 1.76E-05 1.04E-05 4.31E-06 2 6.09E-05 4.75E-05 3.51E-05 2.57E-05 1.64E-05 9.72E-06 6.26E-06 3.57E-06 1.41 E-06 3 1.46E-05 1.13E-05 7.95E-06 5.54E-06 3.50E-06 2.04E-06 1.27E-06 6.95E-07 2.56E-07 5 1.92E-06 1.50E-06 9.86E-07 6.43E-07 4.00E-07 2.30E-07 1.38E-07 7.16E-08 2.42E-08 10 8.44E-08 6.70E-08 3.97E-08 2.33E-08 1.43E-08 8.08E-09 4.60E-09 2.24E-09 6.68E-10 Table 8-1 (continued)-Interpolated Hazard for the Reference Rock Site Condition (T=1.5 sec. to T=3.0 sec.) PSA (g) T=1.5 T=1.74 T=2.0 T=2.5 T=3.0 0.01 9.18E-02 7.10E-02 5.56E-02 3.74E-02 2.74E-02 0.05 7.51 E-03 5.61 E-03 4.24E-03 2.59E-03 1.75E-03 0.1 2.26E-03 1.63E-03 1.19E-03 6.51 E-04 4.05E-04 0.2 6.63E-04 4.35E-04 2.90E-:04 1.33E-04 7.22E-05 0.4 1.50E-04 8.65E-05 5.11 E-05 1.89E-05 8.66E-06 0.8 2.08E-05 1.10E-05 5.95E-06 1.75E-06 6.72E-07 1.5 2.20E-06 1.11 E-06 5.83E-07 1.41 E-07 4.65E-08 2 6.93E-07 3.47E-07 1.80E-07 3.99E-08 1.22E-08 3 1.20E-07 5.95E-08 3.05E-08 5.95E-09 1.65E-09 5 1.06E-08 5.25E-09 2.68E-09 4.39E-10 1.06E-10 10 2.66E-10 1.32E-10 6.79E-11 8.37E-12 1.62E-12

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