As has been said by Dr Michael, magnetic storms are produced by solar activity, Nowadays there many studies about it and some groups measuring it constantly.
it is now being expected a strong magnetic storm in the near future which they suppose will literally burn communication, satellites, internet and electrical system everywhere around the earth.
But I think normal ones can not affect your equipment because they are prepared somehow to stand a certain magnetic level without problems.
Colleagues, you are looking for an earthquake standard. This is the path to nowhere !!! It is necessary to study the trend of the seismic signal !!!. Every earthquake has its own individual trend !!! The problem of the earthquake prediction is finally solved by me !!! See my article, which is posted on my site. Sincerely, Vyacheslav Mikhailovich