Im not sure to be honest , great question... I know when it comes to the geology it can be off from old mapping etc so id assume the same for faults? Curious now as well ...

Hi Travis,

It would depend primarily on the maps you are using, who authored them, and the scale that the data was taken.

Usually there is a way to determine the map-maker's confidence in the location of their contact (faulted or otherwise). GSC maps, for example, use a set of symbols telling you decreasing certainty of trace. In the legend they should say something like observed, interpreted, inferred to convey that certainty, usually with symbols like ——, —.—, –.–.– (respectively) that make it (sorta) clear which is which.

I'm a big fan in knowing who made the map I am looking at and where the info came from. It takes time to figure out who knows what they're doing and who doesn't ...

500m would be a huge error for a gov't scientist making a 1 : 20 000 scale map, but probably not all that bad for someone making a 1 : 250 000 regional map. I always tell the people I go in the field with to take every map they encounter with a huge grain of salt, and to do a bit of investigation into the resources we're relying on. Gov't maps should always be considered a relatively-smart (most of those guys have PhD's and lots of experience now) mapper's best efforts based on the time they had in the field, which may have been minimal due to budget or other concerns. A couple of years back, for example, Myself and Sebo spent three months in an area that I imagine the gov't scientists spent a total of 3 - 5d mapping; our mapping was significantly better as a result. We spent days climbing over and mapping outcrops they probably didn't even see.

Hope this helps. Feel free to get in touch if you are curious about a specific spot, I might be able to help you out.

The BC Faults data set from the BC Data Catalogue is good for regional recon, but that's about it. It will show you the major regional structures, but at the individual drainage level it's up to you to determine faults, shear zones and other structures. I would have expected their faults database to be a bit more comprehensive, but they likely had significant constraints on time, and did the best they could within their scope.