Prvi gmm 251

Major updates to PRVI GMMs

src/main/java/gov/usgs/earthquake/nshmp/gmm/ChiouYoungs_2008.java

@@ -232,7 +232,7 @@ public class ChiouYoungs_2008 implements GroundMotionModel {
     return sqrt(τ * τ * NL0sq + σNL0 * σNL0);
   }
 
-  static class Usgs extends ChiouYoungs_2014 {
+  static class Usgs extends ChiouYoungs_2008 {
     Usgs(Imt imt) {
       super(imt);
     }