Seismic Waves: These are waves of energy caused by the sudden breaking of rock within the earth or an explosion, just like how nudging your table sends shockwaves through your block tower.
Fault Lines: These are fractures in Earth's crust where different sections have moved relative to each other, much like cracks in your table that could cause instability for your block tower.
Richter Scale: This is a numerical scale for expressing the magnitude of an earthquake on the basis of seismograph oscillations; it's like measuring how hard you nudged your table and predicting how much it will shake up your block tower.