From 5a8b8a5e98ef671333e646b9b6632ce028af20e1 Mon Sep 17 00:00:00 2001
From: Peter Powers <pmpowers@usgs.gov>
Date: Wed, 19 Feb 2025 08:56:50 -0700
Subject: [PATCH] MA_03 implementation
---
.../nshmp/gmm/MotazedianAtkinson_2003.java | 131 ++++++++++++++++++
.../gmm/coeffs/MotazedianAtkinson03.csv | 4 +
2 files changed, 135 insertions(+)
create mode 100644 src/main/java/gov/usgs/earthquake/nshmp/gmm/MotazedianAtkinson_2003.java
create mode 100644 src/main/resources/gmm/coeffs/MotazedianAtkinson03.csv
diff --git a/src/main/java/gov/usgs/earthquake/nshmp/gmm/MotazedianAtkinson_2003.java b/src/main/java/gov/usgs/earthquake/nshmp/gmm/MotazedianAtkinson_2003.java
new file mode 100644
index 00000000..fd4b6caf
--- /dev/null
+++ b/src/main/java/gov/usgs/earthquake/nshmp/gmm/MotazedianAtkinson_2003.java
@@ -0,0 +1,131 @@
+package gov.usgs.earthquake.nshmp.gmm;
+
+import static gov.usgs.earthquake.nshmp.gmm.GmmInput.Field.MW;
+import static gov.usgs.earthquake.nshmp.gmm.GmmInput.Field.RRUP;
+import static gov.usgs.earthquake.nshmp.gmm.GmmInput.Field.VS30;
+import static gov.usgs.earthquake.nshmp.gmm.GmmUtils.BASE_10_TO_E;
+import static gov.usgs.earthquake.nshmp.gmm.GmmUtils.LN_G_CM_TO_M;
+import static java.lang.Math.log10;
+import static java.lang.Math.sqrt;
+
+import java.util.Map;
+
+import com.google.common.collect.Range;
+
+import gov.usgs.earthquake.nshmp.gmm.GmmInput.Constraints;
+import gov.usgs.earthquake.nshmp.tree.LogicTree;
+
+/**
+ * Implementation of the preliminary MA05 model that was used for PRVI.
+ * Functional form is the same as MA05 with diffeent coefficients and constants.
+ * Coefficients were gleaned from forttran codes and only three IMTs are
+ * supported (PGA, 0.2 s, and 1 s).
+ *
+ * <p><b>Component:</b> not specified (avg horizontal implied)
+ *
+ * @author U.S. Geological Survey
+ * @see MotazedianAtkinson_2005
+ * @see Gmm#MA_03_PRVI
+ */
+public class MotazedianAtkinson_2003 implements GroundMotionModel {
+
+ static final String NAME = "Motazedian & Atkinson (2003) PRVI Preliminary";
+
+ static final Constraints CONSTRAINTS = Constraints.builder()
+ .set(MW, Range.closed(4.0, 9.5))
+ .set(RRUP, Range.closed(0.0, 1000.0))
+ .set(VS30, Range.closedOpen(150.0, 1500.0))
+ .build();
+
+ static final CoefficientContainer COEFFS =
+ new CoefficientContainer("MotazedianAtkinson03.csv");
+
+ // distance centering coefficients
+ private static final double C5 = -7.333;
+ private static final double C6 = 2.333;
+ // hinge function coefficients
+ private static final double C7 = -1.88;
+ private static final double C8 = 0.14;
+ private static final double DIST_HINGE_LOWER = 75.0;
+ private static final double DIST_HINGE_UPPER = 100.0;
+
+ // convert log10 sigma to ln
+ private static final double SIGMA = 0.28 * BASE_10_TO_E;
+
+ private static final class Coefficients {
+
+ final Imt imt;
+ final double c1, c2, c3, c4;
+
+ Coefficients(Imt imt, CoefficientContainer cc) {
+ this.imt = imt;
+ Map<String, Double> coeffs = cc.get(imt);
+ c1 = coeffs.get("c1");
+ c2 = coeffs.get("c2");
+ c3 = coeffs.get("c3");
+ c4 = coeffs.get("c4");
+ }
+ }
+
+ private final Coefficients coeffs;
+
+ MotazedianAtkinson_2003(Imt imt) {
+ coeffs = new Coefficients(imt, COEFFS);
+ }
+
+ @Override
+ public Imt imt() {
+ return coeffs.imt;
+ }
+
+ @Override
+ public LogicTree<GroundMotion> calc(GmmInput in) {
+ return calc(coeffs, in);
+ }
+
+ private static LogicTree<GroundMotion> calc(
+ Coefficients c,
+ GmmInput in) {
+
+ double μ = calcMean(c, in.rRup, in.Mw);
+ return GroundMotions.createTree(μ, SIGMA);
+ }
+
+ private static final double calcMean(
+ Coefficients c,
+ double rRup,
+ double Mw) {
+
+ /* Eq. 6, log10(PSA) in cm/s/s */
+
+ double r = getR(rRup, Mw);
+
+ double hingeFunction = getHingeFunction(r, Mw);
+
+ double μ = c.c1 + c.c2 * (Mw - 6) + c.c3 * (Mw - 6) * (Mw - 6) + hingeFunction + c.c4 * r;
+ // convert from base 10 to base e and from cm/s/s to g
+ return μ * BASE_10_TO_E - LN_G_CM_TO_M;
+ }
+
+ private static final double getR(double rRup, double Mw) {
+ // Equation and coefficients defined in Table 2 caption
+ double delta = C5 + C6 * Mw;
+ return sqrt(rRup * rRup + delta * delta);
+ }
+
+ private static final double getHingeFunction(double dist, double Mw) {
+ // Equation and coefficients defined in Table 2 caption
+ double mFac = C7 + C8 * Mw;
+ if (dist <= DIST_HINGE_LOWER) {
+ // R <= 75 km
+ return mFac * log10(dist);
+ } else if (dist <= DIST_HINGE_UPPER) {
+ // 75 km < R <= 100 km
+ return mFac * log10(DIST_HINGE_LOWER);
+ } else {
+ // R >= 100 km
+ return mFac * log10(DIST_HINGE_LOWER) - 0.5 * log10(dist / DIST_HINGE_UPPER);
+ }
+ }
+
+}
diff --git a/src/main/resources/gmm/coeffs/MotazedianAtkinson03.csv b/src/main/resources/gmm/coeffs/MotazedianAtkinson03.csv
new file mode 100644
index 00000000..686974e5
--- /dev/null
+++ b/src/main/resources/gmm/coeffs/MotazedianAtkinson03.csv
@@ -0,0 +1,4 @@
+T, c1, c2, c3, c4
+PGA, 3.87, 0.39062, -0.11289, -0.00213
+0.2, 4.33, 0.38815, -0.13977, -0.00189
+1, 3.40, 0.64818, -0.15222, -0.00091
--
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