I love field trips. I enjoy experiential learning out in the field. Fortunately, I have a diverse group of friends from various fields who invite me to their events. My favorite kind of field trips are science field trips where I get to learn about my super smart friends’ worlds. Through my friends, I have been able to get a closer look (get special tours) at really cool places such as JPL and SpaceX. Recently, my friend Matt, an earthquake engineer, and I toured the San Andreas Fault with the Southern California Section of the American Chemical Society.
It was an early Saturday morning road trip to San Bernardino but it was worth it. The group met at Cal State University – San Bernardino, which was pretty much right next to the mountains. The tour was led by Dr. Robert DeGroot, a.k.a. Bob, who was the Project Manager at the Office of Experiential Learning & Career Advancement at the Southern California Earthquake Center at the University of Southern California. Got that? But, at the end of the day, Bob was a chemist at heart. He quipped about his colleagues from “other sciences” such as biology throughout the day. He’s still friends with them.
Bob took our group of 40 or so to the geology lab where he gave us an overview– an orientation– of the items in our packets, the plan for the day, and an activity to get us started. The group was comprised of professionals but there were a couple of families who brought their teenagers. The presentation, as well as the entire day, was very newbie/regular person friendly. I do not have a science background but I understood a lot of the concepts. It also helped that the first activity to explain the basics of tectonic plate movements involved Oreos. The activity was actually created by Robert J. Lillie, who wrote a book called, “Parks and Plates: The Geology of Our National Parks, Monuments, and Seashores.” Science and food… I will have to check out this book.
Below are my takeaways from the lab intro:
- The San Andreas Fault extends from Brawley, near the Salton Sea, to near Eureka, in Northern California.
- The 6.7 magnitude Northridge earthquake ruptured for 7 seconds but shaking was 45 seconds. Then the aftershock.
- What makes a fault slide: 1) sheer force, 2) friction, and 3) cohesion
(This was pretty cool, he used the example of snapping a finger)
- The best way to explain sliding plate over the atmosphere and the plate boundaries (divergent, convergent, and transform) is really only through Oreos.
I thought we were going to drive to the Fault but it was about a 2 kilometer hike from campus. From the campus, you could see where the Fault might be just by looking at the vegetation. You could see that there was a change in landscape, e.g. bushes not present in other parts of the mountain. Bob encouraged us to pick up rocks and feel the dirt in our hands. We stopped several times and he explained to us the geology of the area. For example, Badger Hill was 60 million years old and made up of metamorphic sedimentary rocks. Bob explained the concept of erosion (movement and transport) to us and why some of the rocks we picked up were not jagged (because they have not been transported enough).
- Mountain High Ski Resort is on the San Andreas Fault.
- Faults, in general, have many different strands.
- The San Bernardino Strand of the San Andreas Fault is on the Pacific Plate and the North American Plate.
- On top of Badger Hill, there is a GPS that could detect the plates’ motion in millimeter square. It moves 15 millimeters per year.
- Why everyone is and should be freaking out:
- There have been a 7.8 magnitude earthquake in most of the Fault’s stretch every 150 years, BUT
- the southern portion of the San Andreas Fault (from San Diego to San Bernardino area) has not had one in 350 years.
Someone asked if a bunch of smaller earthquakes– the 5.0 magnitude variety– would be better than just having The Big One. Bob answered it with the spaghetti strand experiment:
- 5.0 magnitude = 1 strand of spaghetti (listen for the crack; look for how it breaks)
- 6.0 magnitude = 32 strands of spaghetti (try to listen for the crack, or if you can even crack it; note how it breaks and how it doesn’t break in the same place)
- 7.0 magnitude = 32 x 1,000 strands of spaghetti
and so on…
- Bottom line: The larger it is, the harder it is to break. But when it finally breaks as a group, notice how each strand breaks at a different place and how, the more strands there are, the more it is all over the place. That’s basically our situation: When The Big One hits, huge and all over the place. That gives a whole different perspective to our 4.5’s, doesn’t it? Like, whatevs.
We hiked back down to the lab to eat our lunch. As I chewed my turkey on white Subway Sandwich which, at that time, tasted like filet mignon after the warm and super breezy hike, I thought about how much nature is all around us, how much is going beneath and above us even when it feels still, and how little most of us know about it.
We all need to take more field trips.
What to do if there is an earthquake: DROP. COVER. HOLD ON.