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 The circulatory system is the system of the human body that is responsible for delivering oxygen, nutrients, and disease-fighting cells to the bodyâs organs and tissues. Parts of the circulatory system include the cardiovascular system, which consists of the heart, lungs, blood vessels, and blood, as well as the lymphatic system, made up of the lymph vessels, nodes, and lymph itself.