Plate Tectonic - Hazards (4)
Pre Lab 

   
OBJECTIVES:
  • Exploring structural damage caused by earthquakes.
  • Discovering that structures can be built to resist shaking from an earthquake.
VOCABULARY:
  • intensity
  • magnitude
  • structure
  • structure damage
MATERIALS:

Students predict structural damage during an earthquake.


Fault break, Turkey

BACKGROUND:

Different types of building materials respond differently to the shaking caused by seismic waves. Materials such as brick and stone break easily during an earthquake. The mortar that typically holds these materials together shakes loose; it has little strength. Brick, stone and mortar structures are very unsuitable dwellings for "earthquake country." In addition, non-bearing walls of bricks or stone are extremely dangerous because they are not structurally part of a house. Wood and steel are much better at withstanding seismic waves. Both of these materials flex as the earth shakes.

Weak materials can be reinforced to make them relatively safe. Reinforcing structures with a steel frame, or driving beams through a structure will help support it during shaking.

PROCEDURE:
  1. Read Three Earthquake Dolls.  Discuss with students what would have fallen down or broken in each situation.  
  2. Draw the chart on the different structures and how they react in an earthquake on the board. Have the students predict how each material will react to the shaking in a moderate earthquake. The answers are written in the diagram, but make the students think before you give them the answers.
 

TYPE

PREDICT HOW MATERIAL WILL 
REACT IN AN EARTHQUAKE

A WOOD BUILDING very good
B STEEL BUILDING good
C BRICK BUILDING poor, especially if not reinforced
D STONE BUILDING poor
E ADOBE BUILDING poor
F GRASS HUT good (if roof is attached)
  1.  Discuss how these structures may be reinforced. If you have the doll house, you may want to discuss ways to reinforce structures inside the house. Go over each room. If you are unfamiliar with reinforcing techniques, the Association of Bay Area Governments website, http://www.abag.ca.gov/bayarea/eqmaps/fixit/fixit.html, has excellent, up-to-date information 
      
  2. Use a world map and go over areas that are prone to disasters caused by earthquake. Point out the area around the Pacific especially from Alaska to Indonesia region; west coast of United States, and Andes Mountains. Areas around the India-China border is also active in earthquakes. Excellent slides are also available from the National Oceanographic and Atmospheric Administration (NOAA) at the website: http://www.ngdc.noaa.gov/seg/fliers/se-0801.shtml.


Red-browns are areas of highest earthquake risk. From Global Seismic Hazard Assessment Program. 

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