Maybe that's logical on the face of it, but what if the electromagnetic signal does not propogate omnidirectionally? That could result in variable amplitudes at the same distance for the same signal.

Furthermore, it is also not valid to assume that there is a linear or exponential relationship between magnitude of the event and the signal. Assume that the signal is generated by the compression of quartz. The signal might be an indicator that a threshold of strain has been reached, which IMPLIES a temblor, but doesn't have any relationship to how long a segment of fault is involved.

It was actually easy to think up two reasons.

Sincerely,

AL in Long Beach