Look at it this way:

The fault zones appear to be generating some type of electromagnetic energy field fluctuation type signal as much as years before an earthquake occurs, perhaps even longer. At first they are probably fairly weak and infrequent but get stronger and more frequent with time. Finally the earthquake occurs. What you have to do is try to learn how to interpret the signals. Just because the time delay is not the same all of the time does not mean that the signals have no value. In my opinion, when it comes to a type of natural disaster which can flatten a city, any information is better than having no knowledge at all regarding its approach.