diff --git a/libs/nshmp-ws/gmm-services/gmm-usage.model.ts b/libs/nshmp-ws/gmm-services/gmm-usage.model.ts
index 6b56cffcc6a6a7bc33a64337db22693f16deb225..a6978831bd4c7bec66a6b8a6d157cd5b18959683 100644
--- a/libs/nshmp-ws/gmm-services/gmm-usage.model.ts
+++ b/libs/nshmp-ws/gmm-services/gmm-usage.model.ts
@@ -26,13 +26,16 @@ export enum GmmType {
   SUBDUCTION_SLAB = 'SUBDUCTION_SLAB',
 }
 
-enum Volcanic {
+export enum GmmGroupType {
+  ALL = 'ALL',
+  ACTIVE_CRUST = 'ACTIVE_CRUST',
+  STABLE_CRUST = 'STABLE_CRUST',
+  SUBDUCTION_INTERFACE = 'SUBDUCTION_INTERFACE',
+  SUBDUCTION_SLAB = 'SUBDUCTION_SLAB',
   VOLCANIC = 'VOLCANIC',
+  PUERTO_RICO = 'PUERTO_RICO',
 }
 
-export const GmmGroupType = {...GmmType, ...Volcanic};
-export type GmmGroupType = GmmType | Volcanic;
-
 /**
  * Gmm usage response in Response object.
  */