Merge branch 'nga-east-mods' into 'main'

NGA-East updates

See merge request !271

src/main/java/gov/usgs/earthquake/nshmp/gmm/ChapmanGuo_2021.java

@@ -33,7 +33,8 @@ class ChapmanGuo_2021 {
       PGV,
       Imt.mprsImts().toArray(new Imt[0]));
 
-  static final double VS_REF = 590.0;
+  static final double VS_REF = 1000.0;
+  static final double Z_CUT = 0.5;
 
   private static final double[] Z = {
       0.0, 0.1, 0.2, 0.3, 0.4, 0.6, 0.8,
@@ -78,6 +79,16 @@ class ChapmanGuo_2021 {
     return data;
   }
 
+  /**
+   * Return the depth scaling factor for application of reference site scaling.
+   * Curently set to 0.0 at z = 0.0 km and 1.0 at z = 0.5 km.
+   *
+   * @param z sediment depth (in km)
+   */
+  static double zSiteScale(double z) {
+    return Math.min(1.0, z / Z_CUT);
+  }
+
   /**
    * Return the psa ratio for the supplied sediment depth, magnitude and
    * distance.

src/main/java/gov/usgs/earthquake/nshmp/gmm/NgaEast.java

@@ -387,6 +387,16 @@ public abstract class NgaEast implements GroundMotionModel {
     }
   }
 
+  public static void main(String[] args) {
+    GmmInput in1 = GmmInput.builder().withDefaults().build();
+    GmmInput in2 = GmmInput.builder().withDefaults().zSed(10).build();
+    GroundMotionModel gmm = Gmm.NGA_EAST_2023.instance(Imt.SA1P0);
+    GroundMotion gm1 = GroundMotions.combine(gmm.calc(in1));
+    GroundMotion gm2 = GroundMotions.combine(gmm.calc(in2));
+    System.out.println(gm1);
+    System.out.println(gm2);
+  }
+
   /*
    * Updated NGA-East for use in the 2023 nshm-conus update. This model includes
    * (1) the final published nonlinear site amplification model of Hshash et al.
@@ -420,15 +430,16 @@ public abstract class NgaEast implements GroundMotionModel {
         double μPga = exp(pgaTables[i].get(p));
         SiteAmp.Value fSite = siteAmp.calc(μPga, in.vs30);
         if (cpa) {
+          double zScale = ChapmanGuo_2021.zSiteScale(in.zSed);
           SiteAmp.Value fCpaRef = siteAmp.calc(μPga, ChapmanGuo_2021.VS_REF);
-          double cpaScale = fSite.siteAmp / fCpaRef.siteAmp;
-          fCpa *= cpaScale;
+          double cpaSiteΔ = zScale * (fSite.siteAmp - fCpaRef.siteAmp);
+          fSite = new SiteAmp.Value(fSite.siteAmp - cpaSiteΔ, fSite.σ);
         }
         μs[i] = fSite.apply(μ) + fCpa;
       }
       double[] σs = new double[] {
           sigmaEpri(in.Mw),
-          sigmaPanel(in.Mw, 3000.0) };
+          sigmaPanel(in.Mw, in.vs30) };
       return GroundMotions.createTree(
           MEAN_IDS, μs, μWts,
           SIGMA_IDS, σs, SIGMA_WTS);
@@ -589,22 +600,24 @@ public abstract class NgaEast implements GroundMotionModel {
           μPga = exp(pgaTables.get(seed).get(p));
         }
         SiteAmp.Value fSite = siteAmp.calc(μPga, in.vs30);
-        double cpaScale = cpa ? cpaScale(μPga, fSite) : 0.0;
-        μs[i] = fSite.apply(μ) + fCpa * cpaScale;
+
+        if (cpa) {
+          double zScale = ChapmanGuo_2021.zSiteScale(in.zSed);
+          SiteAmp.Value fCpaRef = siteAmp.calc(μPga, ChapmanGuo_2021.VS_REF);
+          double cpaSiteΔ = zScale * (fSite.siteAmp - fCpaRef.siteAmp);
+          fSite = new SiteAmp.Value(fSite.siteAmp - cpaSiteΔ, fSite.σ);
+        }
+        μs[i] = fSite.apply(μ) + fCpa;
 
       }
       double[] σs = new double[] {
           sigmaEpri(in.Mw),
-          sigmaPanel(in.Mw, 3000) };
+          sigmaPanel(in.Mw, in.vs30) };
       return GroundMotions.createTree(
           MEAN_IDS, μs, MEAN_WTS,
           SIGMA_IDS, σs, SIGMA_WTS);
     }
 
-    private double cpaScale(double μPga, SiteAmp.Value fSite) {
-      SiteAmp.Value fCpaRef = siteAmp.calc(μPga, ChapmanGuo_2021.VS_REF);
-      return fSite.siteAmp / fCpaRef.siteAmp;
-    }
   }
 
   static abstract class Seed extends NgaEast {

src/main/resources/gmm/coeffs/PZCT18_M1SS.csv

@@ -3,7 +3,7 @@
  0.01,  4.265e-1, 7.075e-1, -7.832e-2, -4.184, 4.091e-1, -6.455e-1,  1.049e-1, -2.056e+0,  2.585e-1, -2.286e-3,  6.653, 6.683e-2
  0.02,  6.573e-1, 6.803e-1, -7.444e-2, -4.088, 3.909e-1, -6.327e-1,  5.930e-2, -2.645e+0,  2.934e-1, -2.045e-3,  6.723, 7.019e-2
  0.03,  3.420e-1, 7.205e-1, -7.437e-2, -3.896, 3.729e-1,  6.628e-3, -1.971e-2, -2.848e+0,  3.026e-1, -2.068e-3,  6.523, 7.611e-2
- 0.04, -1.266e-2, 7.652e-1, -7.558e-2, -3.753, 3.644e-1,  5.479e-1, -6.757e-2, -2.577e+0,  2.711e-1, -2.376e-3, -6.332, 8.139e-2
+#0.04, -1.266e-2, 7.652e-1, -7.558e-2, -3.753, 3.644e-1,  5.479e-1, -6.757e-2, -2.577e+0,  2.711e-1, -2.376e-3, -6.332, 8.139e-2
  0.05, -2.608e-1, 7.963e-1, -7.698e-2, -3.683, 3.639e-1,  7.904e-1, -7.123e-2, -2.094e+0,  2.232e-1, -2.747e-3, -6.190, 8.635e-2
 0.075, -7.995e-1, 9.087e-1, -8.460e-2, -3.587, 3.591e-1,  6.022e-1,  3.520e-3, -1.075e+0,  1.398e-1, -3.319e-3,  6.105, 9.263e-2
  0.10, -1.391e+0, 1.060e+0, -9.486e-2, -3.475, 3.439e-1,  2.369e-1,  6.864e-2, -4.517e-1,  8.967e-2, -3.481e-3,  6.130, 9.041e-2

src/main/resources/gmm/coeffs/PZCT18_M2ES.csv

@@ -3,7 +3,7 @@
  0.01, -1.871e-1, 8.314e-1, -7.503e-2, -3.714, 3.030e-1, -7.793e-1,  1.360e-1, -2.307e+0, 3.093e-1, -2.263e-3,  6.745, 5.637e-2
  0.02,  8.387e-2, 7.934e-1, -7.073e-2, -3.641, 2.898e-1, -7.692e-1,  9.124e-2, -2.885e+0, 3.399e-1, -2.013e-3,  6.814, 5.774e-2
  0.03, -1.786e-1, 8.256e-1, -7.148e-2, -3.489, 2.809e-1, -1.806e-1,  2.319e-2, -3.072e+0, 3.469e-1, -2.043e-3,  6.616, 6.483e-2
- 0.04, -4.947e-1, 8.659e-1, -7.358e-2, -3.378, 2.796e-1,  3.218e-1, -1.611e-2, -2.791e+0, 3.157e-1, -2.365e-3,  6.425, 7.330e-2
+#0.04, -4.947e-1, 8.659e-1, -7.358e-2, -3.378, 2.796e-1,  3.218e-1, -1.611e-2, -2.791e+0, 3.157e-1, -2.365e-3,  6.425, 7.330e-2
  0.05, -7.246e-1, 8.959e-1, -7.568e-2, -3.325, 2.831e-1,  5.318e-1, -1.344e-2, -2.301e+0, 2.693e-1, -2.751e-3,  6.278, 8.156e-2
 0.075, -1.255e+0, 1.009e+0, -8.397e-2, -3.237, 2.809e-1,  3.432e-1,  6.065e-2, -1.289e+0, 1.932e-1, -3.352e-3,  6.184, 9.085e-2
  0.10, -1.849e+0, 1.160e+0, -9.436e-2, -3.125, 2.660e-1,  1.611e-2,  1.168e-1, -6.970e-1, 1.511e-1, -3.519e-3, -6.205, 8.908e-2