Earthquakes

What are Earthquakes?

• Plate tectonics
• Plates make up Earth's thin crust and move
• Plates build up potential (friction) energy and release as kinetic energy (Earthquake)

Forces that Cause Earthquakes

• Divergent Boundaries- (sea floor spreading)
• Convergent Boundaries- (mountains and trenches)
• Transform Boundaries- (larger earthquakes)

Earthquake Waves

• P-Waves (Primary): first detected, horizontal with ground (compression)
• S-Waves (Secondary): second detected, vertical with ground
• Time from P to S wave: radial distance from earthquake epicenter

Himalayas

• Convergent boundary- Eurasian Plate, Australian Plate
• Nepal has population of 28 million
• Four quakes over magnitude 6.0 in past decade
• 10,600 people killed in 1934 earthquake at magnitude 8.0

Earthquake Triangulation

• Triangulation used to locate epicenters
• 3 seismographs used to pinpoint epicenter with converging radii
• Radii found by time from p to s waves

Engineering

• Identify Problem
• Brainstorm
• Design
• Build, test, evaluate, redesign
• share solution

Engineering and Earthquakes

• Structurally stable buildings won't fall
• Less windows mean less broken glass
• Allow building to be flexible
• Better building materials

Loss of Life Reduction

• Education about earthquakes
• Earthquake "safe zones"
• Engineering
• Sirens after p waves

Challenges of Damage Reduction

• Predicting large earthquakes is nearly impossible
• Higher quality engineering is expensive
• People already live in desired homes and lifestyles