The photo-interpretation of
the area was carried out on six aerial photo lines of INEGI (1:75,000),
orthophotos (1:37,500), and panchromatic (5 m)/color SPOT images
at 10mof resolution. The compiled information includedmain lithologic
contacts, faults, fractures, drainage patterns, and mass movement processes.
The morphologic features were identified following the scheme
proposed by Van Zuidam (1985).