The San ANDREAS Fault is a major geological fault line that runs through California in the United States. It is a transform fault, meaning it is a boundary between two tectonic plates that are sliding past each other. The San ANDREAS Fault is responsible for some of the most powerful earthquakes in the region. The term 'San ANDREAS Fault' is derived from the name of the nearby San ANDREAS Lake. The correct answer to the crossword puzzle is 'ANDREAS', which is a 7-letter word.