# 5: Seismology

• 5.0: Introduction to Seismology
In this chapter, we will begin a discussion on seismology, which is the branch of geology that studies earthquakes and how seismic waves move through the earth.
• 5.1: Basics of Wave Propagation
In order to understand some of the more complex aspects of seismology, we must first start at the beginning and get a handle on the basics of wave propagation. In this section, we will examine three primary concepts: (1) The Basics of Waves, (2) Types of Seismic Waves Optics: Reflection, and (3) Transmission (Refraction), and Snell's Law.
• 5.2: Seismic Refraction (Single Layer)
One of the most important uses of seismic waves is for seismic surveys. Seismic surveys can be used to determine shallow (~100s of meters) crustal structure. The surveys shed light on the layers of rock, including each ones thickness and seismic velocity (and from seismic velocity we can estimate rock type). We can also determine structures such as faults and basins, history of deposition, and look for oil and gas.
• 5.3 Seismic Refraction Jupyter Notebook
An interactive example of single-layer seismic refraction. See how the thickness and velocity of different layers affect a seismic refraction model.
• 5.4: Seismic Reflection (Single Layer)
Reflection surveys follow the same basic principles as refraction surveys, except of course they use reflected waves instead of refracted waves. We can use reflected waves to get h and v1, but we cannot get v2 unless we have a reflection from a deeper layer.
• 5.5 Seismic Reflection Jupyter Notebook
An interactive example of single-layer seismic reflection. See how receiver spacing and layer thickness impact a seismic reflection model.
• 5.6: Summary
Let's review what we learned about seismology in this chapter.

Thumbnail: Animation of 2004 Indonesia Tsunami. (Public Domain; National Oceanic and Atmospheri Adme)