This week Los Angeles experienced two earthquakes, one occurring on the Fourth of July and one the following day, on the fifth. The one on Fourth of July was said to be a foreshock with a magnitude of 6.2. It was centered in Ridgecrest, a remote area located 3 hours from Los Angeles. The earthquake on the fifth was 7.1 magnitude, which was much stronger than the first. Though many believe this was the San Andreas fault line, it was actually that Garlock fault line. The Garlock fault line runs from a junction with the San Andreas fault so they are not the same. However, they do connect. If you look at a map of California, you can see it form a “V” shape. The Garlock fault is located in the Mojave Desert. This area is also known as the, “California’s Salad Bowl” because that’s where the United States gets most of our lettuce from. Another interesting fact about the Garlock fault is that the mountains run from East to West, just like the Santa Monica Mountains. These are the very few mountains within the U.S that run this way. Why is that? It’s the result of earthquakes. 

What fault line is Kenneth Hahn and Baldwin Hills Scenic Overlook on?

Currently in the Baldwin Hills Parklands, we are on the Newport-Inglewood fault, which runs 47 miles from Culver City to Newport Beach. This fault line is part of the bigger and the most well known fault line, San Andreas. This fault line is the biggest in the world, running 750 miles from the Gulf of Mexico to Point Reyes. It runs through both the Pacific Plate and the North American Plate. From an aerial point of view the line looks like its just skimming the West side of California, with Los Angeles being the biggest city on the fault line. Kind of scary, right? Now, this may be a load of information but here’s a map to help you see it:

Here’s the San Andreas fault along the Pacific Ocean and the Garlock fault

Tectonic Plate Movements

San Andreas is a transform fault which means that two tectonic plates pass one another in opposite directions. The way we teach students this is by facing both palms down flat and bringing both hands together. Now, moving both hands in the opposite direction. Every bump they felt from their knuckles in an earthquake. There are two other plate movements: convergent and divergent. Convergent is when the plates come together which is how the Himilayan mountains were formed. Divergent is the plates separating usually revealing Earth’s asthenosphere which caused some volcanoes in Hawaii.

You might be asking yourself why this is all important? Well this is what we educate students on at Kenneth Hahn State Recreation Area to teach them about LA’s geology. Most adults don’t even know this information. It’s important for the public to know how these places were created and most importantly what fault line they live on. With the two earthquakes happening right before I give my Geology lesson I think it’s pretty ironic but also very relatable to students that live in the Greater Los Angeles Area. I think living here we have a unique experience and should be well aware what the plate movements mean and the results that happen after an earthquake.

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