San Andreas fault lines
Definition
A series of active tectonic plate boundaries stretching 1,200 km through California, marking the junction between the Pacific and North American plates.
A geologic feature frequently cited as a looming source of significant seismic risk for major Southern California population centers, often referred to colloquially as the origin point of 'The Big One'.
Examples
Trying to predict the exact moment the San Andreas fault lines will trigger 'The Big One' is about as reliable as trusting a weather report five minutes before a storm.
If the San Andreas fault lines decide to have a mid-life crisis, they are certainly picking a dramatic way to vent their stress on the millions of commuters stuck in LA traffic.
Living west of the San Andreas fault lines is the ultimate commitment to an 'only in California' lifestyle where your backyard might suddenly decide to relocate to a different county.
Engineers look at the San Andreas fault lines with the same panicked optimism one might have when ignoring a check engine light that has been glowing since 2012.