From 3b12329eb1867424775cf54fe72b8a57fee1c735 Mon Sep 17 00:00:00 2001
From: Peter Powers <pmpowers@usgs.gov>
Date: Mon, 9 May 2022 07:50:32 -0600
Subject: [PATCH] added depth scaling method
---
.../usgs/earthquake/nshmp/gmm/ChapmanGuo_2021.java | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/src/main/java/gov/usgs/earthquake/nshmp/gmm/ChapmanGuo_2021.java b/src/main/java/gov/usgs/earthquake/nshmp/gmm/ChapmanGuo_2021.java
index 955704ea..7798c15a 100644
--- a/src/main/java/gov/usgs/earthquake/nshmp/gmm/ChapmanGuo_2021.java
+++ b/src/main/java/gov/usgs/earthquake/nshmp/gmm/ChapmanGuo_2021.java
@@ -34,6 +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;
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.
--
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