diff --git a/gradle.properties b/gradle.properties
index 26eadda4faa63fe2f2a0c4464f1d1d555462890b..cf4efbb2aec3a8110236fdeea541539c189d35bf 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -9,7 +9,7 @@ micronautRxVersion = 2.1.1
 nodePluginVersion = 3.0.1
 nodeVersion = 16.3.0
 nshmFaultSectionsTag = v0.1
-nshmpLibVersion = 1.4.13
+nshmpLibVersion = 1.4.19
 nshmpUtilsJavaVersion = 0.4.0
 shadowVersion = 7.1.2
 spotbugsVersion = 4.7.0
diff --git a/src/main/java/gov/usgs/earthquake/nshmp/www/gmm/GmmCalc.java b/src/main/java/gov/usgs/earthquake/nshmp/www/gmm/GmmCalc.java
index ef285d34066e82be80aa31bc54e82c70f08d8a81..d3363524df9ab03544f70a92af12875cf5de67c7 100644
--- a/src/main/java/gov/usgs/earthquake/nshmp/www/gmm/GmmCalc.java
+++ b/src/main/java/gov/usgs/earthquake/nshmp/www/gmm/GmmCalc.java
@@ -52,12 +52,16 @@ class GmmCalc {
           .map(imt -> gmm.instance(imt).calc(request.input))
           .collect(Collectors.toList());
 
+      List<Double> saPeriods = saImts.stream()
+          .map(imt -> imt.period())
+          .collect(Collectors.toList());
+
       gmmSpectra.put(
           gmm,
           new GmmSpectraData(
               treeToDataGroup(gmm, Imt.PGA, request.input),
               treeToDataGroup(gmm, Imt.PGV, request.input),
-              treesToDataGroup(Imt.periods(saImts), saImtTrees)));
+              treesToDataGroup(saPeriods, saImtTrees)));
     }
 
     return gmmSpectra;