diff --git a/src/main/java/gov/usgs/earthquake/nshmp/gmm/AbrahamsonGulerce_2020.java b/src/main/java/gov/usgs/earthquake/nshmp/gmm/AbrahamsonGulerce_2020.java
index b02b7fd99106b1190121d43d39fcf69529c0001e..4f0a28078cbae8043a2a91ecf6f86b9657eec7fb 100644
--- a/src/main/java/gov/usgs/earthquake/nshmp/gmm/AbrahamsonGulerce_2020.java
+++ b/src/main/java/gov/usgs/earthquake/nshmp/gmm/AbrahamsonGulerce_2020.java
@@ -255,7 +255,7 @@ public abstract class AbrahamsonGulerce_2020 implements GroundMotionModel {
     if (in.vs30 < coeffs.vlin) {
       pgaRock = exp(calcMean(
           coeffsPGA, slab(), basin(), adjusted(), akBiasAdjusted(),
-          0.0, in.Mw, in.rRup, in.zTor, VS30_ROCK, in.z2p5));
+          0.0, in.Mw, in.rRup, in.zTor, VS30_ROCK, Double.NaN));
     }
     double μ = calcMean(
         coeffs, slab(), basin(), adjusted(), akBiasAdjusted(),