ENVS 3000 Lecture Notes - Lecture 5: Inverse Relation, Mercalli Intensity Scale, Subduction
Document Summary
Inverse relationship - larger magnitude = less frequency. Accumulated strain is suddenly released in brittle material and the object is deformed in ductile material. When the elastic limit is reached, the rock ruptures, releasing accumulated strain as energy. A fracture spreads from the point of rupture creating a fault and generating an earthquake. Point on the surface of the earth above the focus. Rocks accumulate strain until the elastic limit is reached, then strained rocks rupture, releasing stored strain as energy (seismic waves). Travel faster than s waves, therefore reach seismograph stations/earth"s surface first. Compression waves that cause the ground to move up and down in a vertical motion. Travel slower than p waves, therefore reach seismograph stations/earth"s surface later. Shear waves that cause the ground to move side to side in a horizontal motion. Using the time lag between p waves and s waves arriving at the seismograph station.
