In Mission Viejo, Fault Lines Are Everywhere

We are surrounded by fault lines. Living in Southern California, it’s hard to forget that. What happened in Japan last week is a painful reminder of the sort of damage that can occur when the earth’s crust groans.

The faults closest to Mission Viejo are the Cristianitos fault and the Newport-Inglewood fault zone. Of the two, by far the most dangerous is the Newport-Inglewood fault zone, which runs just off the coast.

The Cristianitos fault hasn’t been active for the last 125,000 years, which is good news for us, since that time range puts it well outside the window for “active” faults. Unfortunately, the same is not true of the Newport-Inglewood fault zone.

The Newport-Inglewood fault zone is what was responsible for destroying Long Beach in 1933. The California Geological Survey considers it “a very dangerous fault.” It’s moved at some point within the last 11,000 years, which in geologic time is closer to saying, “I mowed the lawn last month.” That means it’s due to be mowed again, although you might be able to get by with another month or so if no one’s coming over.

The nearby faults are not, however, the only ones that pose a risk for Orange County. One of the most active faults in the country is the Elsinore fault, which has moved in the last 200 years. The Elsinore fault in particular is a concern because increased activity on that fault causes further stress on the most infamous fault of all, the San Andreas.

Now, a major earthquake along the San Andreas would be bad for just about everyone in Southern California, but in many ways, not as bad as a major quake along the Newport-Inglewood fault zone, since an earthquake there increases the chance of a tsunami.

And I think everyone is frightfully aware of what sort of damage those can cause.