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 role of the circulatory system is to transport oxygen and other necessary nutrients all throughout the body. The main part of the circulatory system is the heart. The heart is the organ responsible for pumping blood throughout the body. This system has three types of blood vessels: The largest are arteries which go away from the heart. Next are veins which lead to the heart and are the second largest vessel.