Merge branch 'site-ngae-edits' into 'main'

Site and NGA-East edits

See merge request !272

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

@@ -34,7 +34,7 @@ class ChapmanGuo_2021 {
       Imt.mprsImts().toArray(new Imt[0]));
 
   static final double VS_REF = 1000.0;
-  static final double Z_CUT = 0.5;
+  static final double Z_CUT = 0.2;
 
   private static final double[] Z = {
       0.0, 0.1, 0.2, 0.3, 0.4, 0.6, 0.8,
@@ -81,12 +81,12 @@ class ChapmanGuo_2021 {
 
   /**
    * 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);
+    double s = 1.0 - Math.exp(-z / Z_CUT);
+    return s * s * s * s;
   }
 
   /**

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

@@ -423,19 +423,19 @@ public abstract class NgaEast implements GroundMotionModel {
       double fCpa = cpa
           ? log(ChapmanGuo_2021.cpaPsaRatio(imt, in.zSed, in.Mw, in.rJB))
           : 0.0;
+      double zScale = cpa
+          ? ChapmanGuo_2021.zSiteScale(in.zSed)
+          : 0.0;
       Position p = tables[0].position(in.rRup, in.Mw);
       double[] μs = new double[MODEL_COUNT];
       for (int i = 0; i < MODEL_COUNT; i++) {
         double μ = tables[i].get(p);
         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 cpaSiteΔ = zScale * (fSite.siteAmp - fCpaRef.siteAmp);
-          fSite = new SiteAmp.Value(fSite.siteAmp - cpaSiteΔ, fSite.σ);
-        }
-        μs[i] = fSite.apply(μ) + fCpa;
+        double cpaSiteCorr = cpa
+            ? siteAmp.calc(μPga, ChapmanGuo_2021.VS_REF).siteAmp * zScale
+            : 0.0;
+        μs[i] = fSite.apply(μ) + fCpa - cpaSiteCorr;
       }
       double[] σs = new double[] {
           sigmaEpri(in.Mw),
@@ -579,6 +579,9 @@ public abstract class NgaEast implements GroundMotionModel {
       double fCpa = cpa
           ? log(ChapmanGuo_2021.cpaPsaRatio(imt, in.zSed, in.Mw, in.rJB))
           : 0.0;
+      double zScale = cpa
+          ? ChapmanGuo_2021.zSiteScale(in.zSed)
+          : 0.0;
       Position p = tables.values().iterator().next().position(in.rRup, in.Mw);
       double[] μs = new double[GMMS.size()];
       for (int i = 0; i < GMMS.size(); i++) {
@@ -600,14 +603,10 @@ public abstract class NgaEast implements GroundMotionModel {
           μPga = exp(pgaTables.get(seed).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 cpaSiteΔ = zScale * (fSite.siteAmp - fCpaRef.siteAmp);
-          fSite = new SiteAmp.Value(fSite.siteAmp - cpaSiteΔ, fSite.σ);
-        }
-        μs[i] = fSite.apply(μ) + fCpa;
+        double cpaSiteCorr = cpa
+            ? siteAmp.calc(μPga, ChapmanGuo_2021.VS_REF).siteAmp * zScale
+            : 0.0;
+        μs[i] = fSite.apply(μ) + fCpa - cpaSiteCorr;
 
       }
       double[] σs = new double[] {

src/main/java/gov/usgs/earthquake/nshmp/model/SiteData.java

@@ -87,7 +87,8 @@ public class SiteData {
     }
     for (Margin margin : margins) {
       Location snapped = snapToGrid(location, margin.spacing, margin.scale);
-      if (margin.contains(snapped)) {
+      // check map because margin data is sparse within polygon
+      if (margin.contains(snapped) && margin.data.containsKey(snapped)) {
         builder.marginValues(margin.data.get(snapped));
         break;
       }