RLNI+2.3

toc

Vocabulary

 * Liquefaction**: when an earthquake's violent shaking suddenly turns loose soft soil into the mud
 * Aftershock**: an earthquake that occurs after a larger earthquake in the same area
 * Tsunamis**: if the earthquake is strong enough, the water displaced by the quake forms large waves
 * Base-isolated buildings**: a building designed to reduce the amount of energy that reaches the building during an earthquake

**How Earthquakes Cause Damage**

 * Local Soil Conditions
 * when seismic waves move from hard, dense rock to loosely packed soil, they transmit their energy to the soil
 * loose soil shakes much more violently than the surrounding rock
 * the thicker the soil is, the more violently the shaking will be
 * this means that if your house is built on solid rock, the shaking will be less than the houses that are built on sandy soil
 * Liquefaction
 * 1964, a powerful earthquake hit Anchorage, Alaska and cracked opened the ground
 * some of the cracks were 9 meters wide
 * some of the cracks were formed by liquefaction
 * liquefaction is likely to happen where the soil has too much moisture
 * as the ground gives way, buildings sink and pull apart
 * during the 1964 earthquake in Alaska, liquefaction
 * caused a landslide that swept thee entire housing development

**Making Buildings Safer**

 * Choice of Location
 * location of the building affects the type of damage it may suffer during an earthquake
 * that housing development went down the cliff and into the sea
 * steep slopes appose to the danger of landslides
 * a filled piece of land can shake violently
 * people should always check what their surroundings is like
 * the farther the structure is, the less shaking there will be
 * Construction methods
 * during an earthquake, a brick building or wood-frame building may collapse if it is not fixed
 * sometimes plywood sheets support frames of wooden buildings
 * to avoid damage caused by liquefaction is to build new homes on solid rock
 * bridges and highways dig down the soft soil and through the firmer ground
 * like the suspension of a car, the pads smooth the car from bumpy rides
 * during an earthquake, a base isolated building sways back and forth without any violent shaking
 * earthquakes indirectly cause floods and fire when the pipes break
 * automatic shut-off valves can be installed to cut off gas and water flow
 * Aftershocks
 * sometimes after an earthquake, there is an aftershock
 * buildings that are weakened by an earthquake, collapse during an aftershock
 * depends when an aftershock might happen
 * aftershocks may strike in hours,days or even months
 * Tsunamis
 * when an earthquake jolts the ocean floor, it starts to rise a little
 * it takes the water out of its way
 * if the earthquake is strong enough, the quake will start to form large waves
 * tsunamis spread out from an earthquake's epicenter and speeds across the ocean
 * the distance between the waves are 100 and 200 kilometers
 * some of the heights of the waves is about the height of a six-story building

**Protecting Yourself During an Earthquake**

 * the main dager of protecting ourself is falling objects
 * it means you need to crouch beneath a table and hold on to it so it won't fall
 * the table helps you protect from falling objects
 * if there is no table near you, then go crouch down to an inner wall
 * cover your neck with your hands
 * if you are outside, go to the middle of the street and stay out of the trees plus the electricity wires