cars, which means it decays at a rate of 2.3% per year. It is estimated that nearly 191,500 kBq/m was leaked during the disaster. How much of the material is still radioactive now, 25 years later? 9. The magnitude of an earthquake is given by the formula Magnitude = log10 In this formula, / is the intensity of the earthquake and I is the minimum intensity for comparison. In 2011, Japan experienced an earthquake where the intensity, I, measured 1 = 1090 * lo. What was the magnitude of this earthquake