The GPS satellites can receive updates from ground stations to adjust ephemeris data. I just received notification from Delorme with updated magnetic declination files for all my mapping products (Street Atlas USA 2003-2004). The north pole has moved enough that current software products and printed maps show an incorrect magnetic north deviation. Those updates were announced BEFORE the quake.
How and Why were they anounced before the quake?? Or were there enough other quakes to make a difference? So what you are telling me, is, I need new software for my gps to work corectly?
Your GPS is fine. The north pole is constantly moving. The magnetic declination corrections are also constantly changing. Delorme decided it was time to issue an update. I received an e-mail notification because I'm a registered, paying customer. The updates were in progress for months before the quake.
If your GPS has a base map that show magnetic lines of declination for a given point, then you might want to track down a firmware update. Garmin MapSource products will probably be appropriately updated soon as well.