Distinguished Lecture

The original lecturer for this week’s distinguished lecture fell ill unexpectedly, so Professor Elizabeth Crook–a teacher in the Earth Systems Science Department at UCI–ended up filling in with an exciting lecture about earthquakes.

 

    First, Dr. Crook told us a bit about herself–she’s a biogeochemist who completed her PhD thesis on ocean acidification by diving and studying coral reefs near UC Santa Cruz. She’s also been a COSMOS director since 2016. 

 

    Dr. Crook started off by explaining to us the definition of Earth systems science, which she defined as when the bio-, geo-, and hydrosphere are studied together in order to understand the interactions between the different parts. These spheres are also known as “reservoirs.”

 

    Next, the students voted for a lecture on earthquakes, so our lecturer began explaining the science behind earthquakes. According to Professor Crook, earthquakes are actually just a rapid release of energy (seismic waves!) due to tectonic stresses. Most earthquakes occur along faults, which makes sense because those are places where different plates move or slip past each other. In addition, the depth determines how much damage an earthquake does–two earthquakes with the same magnitude can have different levels of surface damage. 

 

After that, we looked into the basic tectonic boundaries: convergent, divergent, and transform. Dr. Crook brought out two foam pieces to explain normal versus reverse thrust faults, which are both types of convergent boundaries. In addition, she showed us the differences between tension and compression. We also looked at the different parts of Earth’s surface, including the crust and the asthenosphere.

 

Finally, we learned about different ways to measure earthquakes. The Richter scale, which we all were familiar with, was actually only useful for measuring California earthquakes at the San Andreas fault due to it being a transform boundary. We also learned about the Moment Magnitude, a more useful model for earthquake strength and destructiveness. Finally, we covered the Mercalli Intensity Scale, which measures the actual damage of infrastructure after an earthquake.

 

The most interesting part of the lecture was when we found out that we’re actually extremely overdue for an earthquake here in California! With a recurrence period of 150 years, Southern California’s last large earthquake in 1857 means we’re at risk of a large earthquake (magnitude 7.0+) at any point. Northern California is also overdue for an earthquake as well, especially in the Seattle region, where a convergence boundary could also cause a devastating tsunami.

Despite missing out on the originally planned lecture, we all enjoyed learning about earthquake science, and “quaked” in our boots as Dr. Crook described the many devastating natural disasters of the past century.