Chapter 5 Lesson 3 Objectives:

1. Explain where most Earthquakes in the U.S. occur

2. Describe how scientists measure Earthquakes

3. List ways to make your classroom and home more earthquake safe.

Rough Outline I. Earthquake Activity A. Studying Earthquakes B. Measuring Earthquake Magnitude C. Past Earthquakes D. Describing Earthquake Intensity E. Liquefaction F. Tsunamis G. Tsunamis Warnings II. Earthquake Safety A. Quake resistant Structure B. Before an Earthquake C. During an Earthquake D. After an Earthquake

I. Earthquake Activity

Earthquakes are used to study the inside of Earth

A. Studying Earthquakes Seismologists: scientists who study

earthquakes.

B. Measuring Earthquakes Magnitude

Magnitude: Measure of the energy released during an earthquake

The Richter Scale: • Scale used to describe the strength of an

earthquake • Has no upper limit – 9.5 would be about the

highest • For each increase of 1.0 the height of the line on

a seismogram is 10x greater or 32 times as much energy is released.

C. Past Earthquakes

1999 – Turkey - 7.8

1556 Shensi, China

1906 – San Francisco Cal.- 8.3

1975 Laoning Province, China – 7.5

First, the water level in a pond inexplicably plunged. Then, thousands of toads appeared on streets in a nearby province. Finally, just hours before China's worst earthquake in three decades, animals at a local zoo began acting strangely.

1990 IRAN 7.7

2001 INDIA 7.7

2003 North Algeria 6.8

2010 Haiti 7.0 (over 300,000)

2010 Chili 8.2

D. Describing Earthquake Intensity

Modified Mercalli Scale: Measure the amount of damage they cause.

Damage depends on: 1. Strength of

earthquake 2. Surface material 3. Design of structures 4. Distance from

epicenter

E. Liquefaction

Occurs when wet soil acts more like a liquid during an earthquake.

Causes buildings to sink into the soil and collapse

F. Tsunamis

Ocean waves caused by earthquakes

G. Tsunami Warnings

1. Water along the shoreline might move rapidly toward the sea, exposing a large portion of land that normally is underwater.

2. Pacific Warning System near Hawaii predicts arrival times

II. Earthquake Safety 1. Don’t live in an area prone to earthquakes

A. Quake-Resistant Structures

In new buildings: Seismic-safe structures: Structures with rubber bands around then

area more likely to withstand the “earthquake.”

In older buildings Installation of steel rods to reinforce building

walls

B. Before an Earthquake

1. Move heavy objects to lower shelves 2. To reduce fires make sure all water

heaters and other gas appliances are secured

3. Placing sensors on gas lines

C. During an Earthquake

Indoors 1. Move away from windows 2. Seek shelter in doorways or under tables

Outdoors 1. Stay in the open away from power lines 2. Stay away from buildings

D. After an Earthquake

1. Shut off any gas lines 2. If you don’t know how to shut lines leave

immediately 3. Call 911 4. Stay away from damaged buildings 5. Be careful of broken glass – wear sturdy

boots 6. Stay away from beaches