Today’s M=5.1 Oklahoma quake followed a M=3.9 shock (in red) located 1.5 km (1 mi) to the southwest

Today’s M=5.1 Oklahoma quake followed a M=3.9 shock (in red) located 1.5 km (1 mi) to the southwest

Today’s M=5.1 Oklahoma quake followed a M=3.9 shock (in red) located 1.5 km (1 mi) to the southwest