This site is designed to help students when interpreting the results of building contest and shake table testing First the difference between earthquake hazard and risk is explained The author then explains earthquake magnitude including how it is measured and calculated the scales used to measure it and what it means in real terms Several charts are used to show the frequencies of difference magnitudes The subject of intensity is enhanced by a chart of the Modified Mercalli Intensity Scale and intensity distribution maps using both rapid instrumental intensity maps and peak horizontal acceleration maps