Earthquake Hazards: Building Design and Construction, and Liquefaction
Building Design and Construction
- strength and flexibility of materials and design
- wood houses are generally very safe
- size/proportions of the building
- single-family homes generally have a low and squat geometry
- however, if you shake long enough, or is the building is on soft ground, even a wood-framed building will fail
- this often means the building fell off its foundation
Liquefaction
- shaking causes unconsolidated soils and sediments to liquify
- ground loses cohesion and flows
- buildings fall down, can remain intact
- soil/sediment grains are touching in many places
- little space between grains so the ground is strong
- vibrations wiggle the grains, resulting in an increase in water pressure
- space between grains increases
- grains can move easily so water can flow
- as soon as shaking stops, water pressure decreases
- grains touch and soil becomes firm again