Anatomy of an Earthquake: A Visual Explainer
A single labelled flowchart tracing how an earthquake originates at its Focus and radiates outward as P-waves, S-waves and surface waves toward the Epicentre.
📌 Revision Pointers
Focus (Hypocentre) = point INSIDE the crust where rupture begins; Epicentre = point on the surface directly above it.
Order of arrival at a seismograph: P-waves (fastest, travel through solids/liquids/gases) > S-waves (slower, solids only) > Surface waves - Love & Rayleigh (slowest, but cause the most damage).
The time gap between P-wave and S-wave arrival at a seismograph is used to calculate that station's distance from the epicentre.
One clean labeled diagram showing the Focus-Epicentre relationship and the three seismic wave types in their order of arrival.
💭 Conclusion
A frequently tested Prelims diagram - know the Focus/Epicentre distinction and that surface waves, despite arriving last, cause the most structural damage.