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.
Your circulatory system pumps your blood though out your whole body. Your heart, your lungs, and your blood vessels work together to form. the circle part of the circulatory system. Your heart is beating all the. time. When your heart beats it pumps blood, the blood goes through. tubes that go all around your body and comes back to your heart.