The Richter scale doesn't measure quake damage (see: Mercalli Scale) which is dependent on a variety of factors including population at the epicentre, terrain, depth, etc.
The circulatory system works with the muscular system, the nervous system, and the digestive system. The heart is a muscle so it is part of the muscular system. Also the heart and lungs have nerves so it is also part of the nervous system.
Combined with the cardiovascular system, the circulatory system helps to fight off disease, helps the body maintain a normal body temperature, and provides the right chemical balance to provide the bodyâs homeostasis, or state of balance among all its systems.