Category Archives: Ventura County

This website started off covering a small area, the Santa Clarita Valley. I later started a second website for the San Diego area. Both sites were somewhat limited in scope. Now, with those sites combined, I’ve also increased the area that the website covers. The new name for the site, Southern California Regional Rocks and Roads seems to state a much larger area. What really is Southern California and what does part of it does this website really cover?

The region, Southern California, or So Cal by some, varies by definition. My definition isn’t exactly a standard one either but I think it is the best fitting one. Southern California is usually defined as the whole of Ventura, Los Angeles, Orange, San Bernardino, western Riverside, and San Diego Counties. This constitutes much of the populated section as well as the area west (or south) of major mountain ranges. This definition leaves out quite a large area, however. It really should be “Coastal Southern California”. How do I then define Southern California and what area I plan to cover with this website? I personally define Southern California as the area south of the 119 degree line, which tends to define the northern boundaries of San Luis Obispo, Kern, and San Bernardino Counties. This site, however, will cover a smaller portion of that region. This website will cover, eventually, the region encompassing all of Santa Barbara, Ventura, Los Angeles, southern Kern, San Bernardino, Riverside, Orange, Imperial, and San Diego Counties.

I’ve sometimes termed this website to be a “monster”. Why do I? Every time I think it is “done”, I come up with more projects to expand the site. There is a lot to cover here in Southern California and I intend to do the best job that I can for the scope of the site. Defining those boundaries will help to at least partially limit the site’s growth.

California, Disaster, Earthquake, Fault, Geology, Los Angeles, Los Angeles County, Orange County, Riverside County, San Andreas Fault, San Bernardino County, San Diego County, Ventura County

Earthquakes and Movies

May 27, 2015 Michael F Ballard Leave a comment

Lately, there has been quite a bit of press about the recent “San Andreas” movie. To me, this movie sets back the general public’s knowledge and understanding about how earthquakes create damage in Southern California.

Some basic stereotypes exist in the movie, many of which are completely false. Starting with the magnitude of the earthquake in the movie – No fault line in Southern California is capable of anything larger than about an 8.2. The only one truly capable of such an event, the San Andreas Fault, is also many miles from Los Angeles and is mostly separated from the Los Angeles Basin by the San Gabriel Mountains. Anything larger than a 9.0 is in the domain of “megathrusts” or subduction zones. In California, the only subduction zone is the southern end of the Cascadia Subduction Zone, which ends at the “Mendocino Triple Junction” just offshore of Cape Mendocino. It last produced something close to a 9.2 or so in January 1700.

Tsunamis, especially ones of great height, are also not in the forecast for a large earthquake here in Southern California. Tsunamis are created by the large scale displacement of water, similar to sloshing in a bathtub. Move your hand below the water quickly, you create a wave on the surface. Usually, tsunamis that are related to earthquakes are caused by the movement of the fault itself, typically megathrust faults underneath the ocean. We just don’t have those in Southern California. Even the largest tsunami generated by such a fault may only be tens of feet high, certainly not hundreds of feet.

Big cracks just don’t open up in the land from earthquakes, certainly nothing like those represented in the movie. Fissures are created by earthquakes, however. These fissures are usually the result of settlement or fault movement. They aren’t that large either way.

Structural damage is also not going to be as great as represented. Mind you, a large magnitude earthquake centered in the Los Angeles Basin will do a great deal of damage. Water mains, sewer mains, gas lines, power lines, and other utilities will be compromised in many locations creating shortages and, in some cases, fires. Buildings may collapse or be damaged beyond repair. The underlying geology will determine some of the damage extent. The rest will be determined by building type and its susceptibility to seismic waves. Either way, the skyscrapers in Downtown Los Angeles won’t be toppling like trees anytime soon. I’d still stay away from the area after a major event though, as there would be an immense amount of glass and debris creating hazards for travel.

Keeping all this in mind, and also keeping with the theme that Southern California officials have been doing, use this opportunity to prepare yourself for a major earthquake. They can strike at any time and will create problems for all of us that live, work, and visit this region. The best way to survive a major catastrophe is to be prepared. Part of that preparation is to know your region, know the routes, and know where the problem areas may be following a major earthquake.

For further information, I highly recommend contacting your local Emergency Services agency in your city and county. They have a great deal of resources to help you prepare for an event like a major earthquake.