The magnitude M of an earthquake is measured using the formula M=log(x/c) , where x is the measured amplitude of a seismic wave and c is the reference amplitude of one micron. Two earthquakes are measured. The amplitude of a seismic wave in the first earthquake is 15 times the amplitude of a seismic wave in the second earthquake. How much greater is the magnitude of the first earthquake than the second earthquake? Round your answer to the nearest hundredth.