Introduction to Seismology

This course is divided into three parts. It starts with an introduction to the dynamics of diverse seismic sources, e.g., volcanic, tectonic, glacial, fluvial, oceanic, atmospheric, and artificial processes, which routinely shake the subsurface. The second part will present the following key topics in elastodynamics that guide the propagation of the waves originating from these seismic sources: types of elastic waves from a point dislocation sources; ray theory, travel-time function in layered media, turning points; plane waves in a homogenous medium and at interfaces; Snell’s law; Earth’s anisotropy; shear-wave splitting; seismic attenuation; surface-wave propagation and dispersion; free oscillations of the Earth. The final part connects the first two and introduces methods that not only help us infer the Earth’s structure but also study the source physics from the seismic measurements. Some motivating examples pertaining to the concepts discussed in this part include: 1. ground-motion measurements nearby rivers can be used to quantify river physics; 2. small earthquakes occurring in and around volcanoes help us understand how volcanoes work and where molten rock (magma) is moving underground; 3. the study of icequakes to study glacier motion in glacier seismology; 4. ambient seismic noise can be used to monitor the seasonal changes in the subsurface; 5. a rapid estimation of the epicentre from the seismic waves generated by the earthquakes makes tsunami warnings possible because these waves travel considerably faster than tsunami waves.

References

• Aki, Keiiti, and Paul G. Richards. Quantitative seismology.
• Chapman, Chris. Fundamentals of seismic wave propagation.
• Shearer, Peter M. Introduction to seismology.