The San Madrian Fault is a continental transform fault that extends for hundreds of miles through the state of California. It is one of the largest and longest fault lines in the world. The San Madrian fault has been responsible for most of the major earthquakes in California, including the San Francisco Earthquake of 1906.
There are many branches (sometimes called tributary faults) connected to the San Madrian fault. One of these branches is the Angelo fault.
During Col. Austin's first encounter with Sasquatch (The Secret of Bigfoot), he and Oscar Goldman were representing the OSI in a U.S. Geologic Survey project that involved planting earthquake predicting sensors along the San Madrian fault and its branches. Austin, Goldman, and Tom Raintree were stationed at a base camp along the Angelo fault when they first encountered Sasquatch. This base camp was referred to as Geologic Survey Base San Angelo.
Real WorldThe San Madrian fault is a fictional stand-in for the San Andreas fault. When Steve and Oscar are flying over the San Madrian fault in a helicopter, stock footage of the San Andreas fault is used to represent the San Madrian. On the DVD audio commentary for this episode, writer Kenneth Johnson admitted that he was not sure why the name of the San Andreas was changed to San Madrian. He surmised that it was "broadcast standards not wanting to offend the San Andreas."
Fictional Geography or Alternate Naming
The fictional geography of the Bionic Universe includes completely unique locations with no particular reference in the real world (for instance Bagaria or Melanique). In some cases, the fictional location is an analogue for a real world location, thus the similarities may be close, but never exact (for instance the Dominion of Balinderry or Eretz).
However, in the case of the San Madrian, it is a perfect duplicate of the San Andreas fault. It occupies the same location as the San Andreas; it looks like the San Andreas from the air; and it is historically linked to the 1906 San Francisco earthquake, which was the result of shifting in the San Andrea fault in the real world. Thus, it is reasonable to assume that in the Bionic Universe the San Madrian is the San Andreas, but through some alternate history, it was given the name San Madrian rather than San Andreas.
The Angelo fault however, is a fictional branch. It is only referred to as the Angelo fault or Angelo tributary throughout the episode. The only time that San Angelo is mentioned is when Tom Raintree is communicating with Washington by radio and calls the camp "Geologic Survey Base San Angelo." San Angelo may be the name of a fictional community or region, or it may be the proper name of the branch fault.
(The Secret of Bigfoot - Parts I and II)