diff --git a/src/main/java/gov/usgs/earthquake/nshmp/gmm/GroundMotionTables.java b/src/main/java/gov/usgs/earthquake/nshmp/gmm/GroundMotionTables.java
index e134e00b0c466ec02650d98b363e723f60431f49..77362debaef48d2f8c329fe6faab91c48f855bfa 100644
--- a/src/main/java/gov/usgs/earthquake/nshmp/gmm/GroundMotionTables.java
+++ b/src/main/java/gov/usgs/earthquake/nshmp/gmm/GroundMotionTables.java
@@ -2,14 +2,17 @@ package gov.usgs.earthquake.nshmp.gmm;
 
 import static com.google.common.io.Resources.getResource;
 import static com.google.common.io.Resources.readLines;
+import static gov.usgs.earthquake.nshmp.Text.NEWLINE;
 import static gov.usgs.earthquake.nshmp.Text.Delimiter.COMMA;
 import static gov.usgs.earthquake.nshmp.Text.Delimiter.SPACE;
-import static gov.usgs.earthquake.nshmp.Text.NEWLINE;
 import static gov.usgs.earthquake.nshmp.gmm.Imt.PGA;
 import static gov.usgs.earthquake.nshmp.gmm.Imt.PGV;
 import static gov.usgs.earthquake.nshmp.gmm.Imt.SA0P03;
 import static gov.usgs.earthquake.nshmp.gmm.Imt.SA0P3;
 import static gov.usgs.earthquake.nshmp.gmm.Imt.SA3P0;
+import static gov.usgs.earthquake.nshmp.gmm.SubductionZone.ALASKA;
+import static gov.usgs.earthquake.nshmp.gmm.SubductionZone.CASCADIA;
+import static gov.usgs.earthquake.nshmp.gmm.SubductionZone.GLOBAL;
 import static java.lang.Math.log10;
 import static java.nio.charset.StandardCharsets.UTF_8;
 import static java.util.stream.Collectors.toList;
@@ -19,6 +22,7 @@ import java.net.URL;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.EnumMap;
+import java.util.EnumSet;
 import java.util.HashMap;
 import java.util.LinkedHashSet;
 import java.util.List;
@@ -357,7 +361,7 @@ final class GroundMotionTables {
   private static Map<SubductionZone, Map<SubductionZone.Type, Map<Imt, GroundMotionTable>>> initKbcg20() {
     Map<SubductionZone, Map<SubductionZone.Type, Map<Imt, GroundMotionTable>>> map =
         Maps.newEnumMap(SubductionZone.class);
-    for (SubductionZone zone : SubductionZone.values()) {
+    for (SubductionZone zone : EnumSet.of(GLOBAL, CASCADIA, ALASKA)) {
       Map<SubductionZone.Type, Map<Imt, GroundMotionTable>> kindMap =
           Maps.newEnumMap(SubductionZone.Type.class);
       for (SubductionZone.Type kind : SubductionZone.Type.values()) {