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 moves nutrients to the cells of the body to feed them and help them fight disease. The main parts of the Circulatory System are the heart, blood and blood vessels. Arteries carry blood and the oxygen in it from the lungs to all of the other cells of the body.