--- tags: geol 420 website page --- # Seismic Refraction Summary Things to think about ... - Illlustrate how the refraction method and concept of "1st Arrivals" works - What is a P-wave? What physical parameters affect its speed? - Why use refraction, can't you just use resistivity? - Why do we swing the hammer so many times??? - What is critical distance? - What is crossover distance? - How deep can a seismic refraction survey see and why? - Why do we have to hit the hammer from both sides? - If I have an idea of what the subsurface looks like, what would the seismic refraction data look like? - What happens if the P-wave velocity of a deeper layer is **less** than the layer above it? - How thin of a layer can a refraction survey detect? - What types of subsurface anomalies (compared to relatively simple homogeneous layers) detect, and **not** detect? - Do refraction surveys match electrical surveys in terms of the layers they detect? - ... etc ...