If you're constantly looking at the System Map, you're gonna get buzz crashes. It's unfortunate, especially for us explorers. But luckily, Gary said that they have located the memory leak that is causing it and the problem will be fixed in the upcoming 1.6 update.
Yeah, I do this when I'm playing at home and I've only ever had the System Map issue after 4hrs+ of exploring. Holding the power button down for 10seconds+ (Or until the Xbox switches off) does a similar thing if you can't get to your power sockets.
Another solution is to turn 'instant on' to off or use the power saving option instead in the Xbox power options, it clears the cache every time you switch off then. I've no doubt this issue will be improved once the 1.6 patch appears