GEOL 1 Lecture 4: Geol_1_-_Lecture_4

• School: Irvine Valley College
• Department: Geology
• Course: GEOL 1
• Professor: Schneider

Document Summary

Patterns in earthquake depths at trenches: earthquake depths are shallowest nearest trenches, they get deeper away from the trench, this is due to an ocean plate diving down under another plate. Measuring the size of earthquakes: two ways to measure earthquake size. Intensity measures how the quake affected people and buildings: magnitude measures the amount of energy released by the earthquake. Magnitude: measures the amount of energy released by the earthquake, small earthquakes are very common, big earthquakes are very rare, logarithmic scale, for every increase of 1 in magnitude, the earthquake is 10 times stronger. Richter magnitude: introduced by charles richter in 1935, based in amplitude of the largest seismic wave recorded. Is only really effective for nearby earthquakes (local earthquakes) Destruction by shaking: amount of structural damage attribute to earthquake vibrations depends on 4 factors, 1. Shaking is about the same everywhere within 12-30 miles of the epicenter, but then rapidly decreases further away: 2.