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.
The circulatory system, sometimes called the cardiovascular system, consists of the heart, blood vessels, and blood. The heart provides the muscle needed to pump blood throughout the body. Blood vessels are the conduits through which blood is transported and blood contains the valuable nutrients and oxygen that are needed to sustain tissues and organs.