Glen...one post above mentions shoring problems due to creep. But, the one just above seems to be talking about how fast the blocks are moving past each other at a distance from the fault, and this need not be creep. For example, the blocks on either side of the San Andreas fault are moving past each other at about 3 1/2 cm/yr, but the fault is locked, meaning not creeping anywhere near the surface. The rocks are essentially flexing. Farther northwest than Parkfield, the San Andreas fault does creep, and then it splts into various strands in the Bay area, some of which creep or partially creep. Creep meaning that the shallow part slides without large earthquakes.

So, my questions are: does the mine actually cross the Elsinore fault? If so, are the shoring problems due to creep, or is it just the bad ground you would expect around an active fault zone? If creep, one might notice an actual offset of the mine tunnel or manmade features within the tunnel such as rail tracks or air pipes or whatever. I suppose the creep could be very small and hard to see without careful surveying. For example, if creep is 1 mm/yr, would take 25 years to make 2 1/2 cm (1 inch).

I've seen open cracks right along the outcrops of both the Santa Cruz Island fault and the related Santa Rosa Island fault (in different decades, back when I actually looked at rocks rather than exlusively sat on my butt in front of computer. These cracks may have nothing to do with creep; they could be due to shrinking and swelling of fault gouge depending on rain or drying.

Chris