diff --git a/src/Shocks.hh b/src/Shocks.hh
index 6a02e1e364649c32ae5e973fb701c11ce8d03bd9..c1879ad16f85df5839544158b8164ed69204c7ab 100644
--- a/src/Shocks.hh
+++ b/src/Shocks.hh
@@ -159,7 +159,6 @@ public:
   using group_t = vector<Group>;
 private:
   group_t shock_groups;
-  vector<string> group_names;
   string name;
 public:
   ShockGroupsStatement(group_t shock_groups_arg, string name_arg);