KYTL+2.3

toc

Vocabulary

 * Liquefaction**-process by which a earthquake's violent movement suddenly turns loose soil into liquid mud
 * Aftershock**-an earthquake that occurs after an larger earthquake in the same area
 * Tsunami**- a giant wave caused by an earthquake
 * Base****-isolated building**- building mounted on bearings designed to absorb the energy of an earthquake

Summary

 * January 1995 earthquake
 * Kobe, Japan
 * lasted for 20 seconds
 * caused damage like thousands of buildings collapsed, a lot of crumpled freeways, 130 fires, 5,000 people disappeared
 * most buildings- wood framed, heavy tiled roof

How Earthquakes Cause damage

 * severe shaking produced by seismic waves can damage or destroy buildings and bridges, utility poles may fall, and gas and water mains can break
 * Local Soil Conditions
 * when seismic waves move from hard, dense rock to loosely packed soil; they transfer their energy to the soil
 * the thicker the layer of soil, the harder the shaking will be
 * a house built on solid rock will not shake as much as a house built on sandy soil
 * Liquefaction
 * 1964 earthquake, Anchorage, Alaska
 * cracks opened in the ground (9 meters wide)
 * cracks created by liquefaction
 * liquefaction-likely to happen where soil is moist
 * as ground gives way, buildings sink/pull apart
 * can trigger landslides
 * Aftershocks
 * may occur hours, days, or even months later
 * buildings weakened by the earthquake often collapsed during an aftershock
 * Tsunamis
 * plate movement causes the ocean floor to rise slightly and push water out of its place
 * in the ocean, the distance between the waves of a tsunami is very long (100-200 kilometers)

Making Buildings Safer

 * to reduce earthquake damage:
 * new buildings-made stronger/flexible
 * older buildings- must be changed to withstand stronger quakes
 * Choice of location
 * steep slopes- cause landslides
 * filled land- shakes violently
 * avoid buildings near faults
 * the farther a building- less strong shaking will be
 * Construction Methods
 * brick/wood framed buildings- collapse if not reinforced
 * plywood sheets- used to strengthen frames of wooden buildings
 * new building on soft ground-anchored to solid rock below soil
 * bridges/highway overpasses- built on supports that go down through soft soil to firm ground
 * fixed-base building- tilts/cracks during earthquakes
 * base-isolated building- upright during earthquakes
 * base-isolation bearings- bend/absorb energy of seismic waves
 * fire/flooding-when gas pipes/water mains break

Protecting Yourself From an Earthquake

 * drop, cover, and hold on
 * crouch beneath a table/desk
 * hold on table/desk so it won't wobble
 * if no table/desk is available, crouch against a interior wall and cover your head/neck with hands
 * make sure to avoid windows, mirrors, wall hangings, and furniture that may fall
 * if outdoors move to open area, and avoid these:
 * vehicles
 * power lines
 * trees
 * buildings
 * and especially brick walls/chimneys(brick kinds)
 * you should have an emergency kit
 * it should contain these items:
 * water
 * first aid
 * canned food