The Newport-Inglewood-Rose Canyon Fault (as it's official name is called) is one of the major fault zones in Southern California. It runs from the southern base of the Santa Monica all the way through downtown San Diego before ending in the San Diego Bay. Its about 120 miles long and goes through very densely populated regions including Century City, Inglewood (right next to Sofi Stadium and close to LAX), Long Beach, Seal Beach, Huntington Beach, and Newport Beach (where it goes offshore). It doens't reappear onshore until La Jolla in San Diego and it runs through Old Town San Diego, runs right next to San Diego International Airport, and then goes into downtown San Diego before going into the San Diego Bay.
It is part of the larger San Andreas Fault system, which is a collection of active faults that help to accommodate the right-latteral strike slip plate motion between the Pacific and North American plates. What is really striking is that if you look at a map of the known oil fields in Southern California, some of them can be connected to make a near perfect line. Notice how the Newport-Inglewood fault matches up perfectly with several of the oild fields below.
This is because faults act as a natural trap to oil as they rise from below. More on this if you visit one of my nearby earthcaches: GCADKNB. But first lets discuss the uniqueness of this site along the Newport-Inglewood-Rose Canyon Fault.
Before an earthquake
After an earthquake
If you have ever driven from the 405 to PCH using Seal Beach Blvd., you may have noticed a slight "bump" or elevation change in the roadway right about where GZ is. This is not here by accident. Instead, it is a fault scarp formed by many earthquake cycles along this fault system. A fault scarp is a topographic feature in the landscape that shows vertical offset of a fault. While the Newport-Inglewood-Rose Canyon fault is classified as being a right-lateral strike strip fault (horizontal motion), it does contain some vertical motion and is more aligned to being an oblique fault (or a fault that contains both horizontal and vertical motion.
The last time this fault ruptured was in 1933 during the Long Beach Earthquake. This fault has the potential to produce up to magnitude 7 earthquakes and can cause considerable damage due to its close proximity to highly dense population centers. In that regard, the Newport-Inglewood-Rose Canyon fault to some is more dangerous than the San Andreas Fault.
Works Cited
https://www.iris.edu/hq/inclass/animation/fault_oblique_
https://www.softstoryretrofitpros.com/blog/post/did-you-feel-it-37-quake-shakes-los-angeles--how-to-protect-your-home
ttps://en.wikipedia.org/wiki/Huntington_Beach_Oil_Field
TO LOG A FIND ON THIS CACHE YOU MUST ANSWER ALL THE QUESTIONS BELOW. YOU CAN CONTACT ME THROUGH MY EMAIL OR THE GEOCACHING MESSAGE CENTER TO SEND YOUR ANSWERS. ANY INCORRECT ANSWERS MAY RESULT IN A CLARIFICATION RESPONSE FROM ME.
1. "Newport-Inglewood Fault - Seal Beach" on the first line of your email AND list all geocaching names of your party so I can match your answers to them. If you all want to learn something, I would prefer each cacher send me individual emails in the spirt of earthcaching.
2. Take a photo of you (or your signature item if you don't want to show your face) with the Newport-Inglewood-Rose Canyon Fault scarp in the background.
3. As you face the fault scarp, look to your left and then look to right. Estimate the length of this scarp AND estimate the average height.
4. Based on your answer to question 3, do you think this is a mature fault scarp (i.e. one that has formed over many earthquake cycles) or do you think this formed during the most recent earthquake (the 1933 Long Beach Earthquake)? How can you tell?
5. Over many earthquake cycles, do you think this scarp is growing or shrining? Is the scarp growing from each earthquake or is it shrinking from erosion removing it faster than the land can move? Explain your answer using you own observations and answers to the previous questions.
6. Looking around this busy intersection, what other evidence do you see that would suggest an active fault is nearby? Hint: see GCADKNB