Earthquake Damage and Earth’s Interior

Factors contributing to damage Duration Intensity Building Design – reinforced/flexible buildings best Materials built on – hard, dense material the best Liquefaction - when loose sediments are saturated with water, during an earthquake, shaking creates a liquid like material not able to support structure – structure sinks

Tsunamis – sea waves caused by an earthquake that displaces the ocean floor vertically water is pushed upwards and toward the land speeds of km/hr low waves in open water – as wave nears shore water builds upwards Tsunami warning system – world wide - alerts about danger

Other Dangers Fires - from broken gas pipes and falling power lines Landslides – rock and soil slide downhill from shaking

Predicting Earthquakes No predicting devices Only measurements – stress along faults, water level in wells, gas emissions from fractures Seismic gap – time between earthquakes

The Earth’s Interior Knowledge of Earth’s interior comes from Earthquake waves By measuring the speed of a wave - able to determine the composition of the Earth  P waves travel through liquids and solids  S waves travel only through solids

As P waves travel they bend as they enter new material - bending shows change of material S waves not traveling through the outer core also shows change in material Conclusion – Earth is made up of different states of material

Layers of the Earth Crust: Thin rocky layer  oceanic crust +/- 7 km thick  continental crust 8km -75 km thick Mantle: Solid, rocky shell – depth of 2890 km  80% of Earth’s volume

Core: Iron and nickel center  Outer Core – 2260 km thick - liquid - Earth’s magnetic field produced here  Inner Core – sphere with radius of 1220 km - solid because of the pressure