earthquakes

GRADE 8 SCIENCE UNIT 2: EARTH AND SPACE

MODULE 1:

EARTHQUAKES AND FAULTS

krisannmaeyapbonilla Subic National High School

At home before an earthquake:

Grade 7

Discover that our country’s location near the equator and along the Ring of Fire influences what makes up

the Philippine environment (e.g. natural

resources, climate).

Grade 8

Being located along the Ring of Fire, the Philippines is prone to

earthquakes. Using models, explain how earthquakes are generated by faults. Try to

identify faults in the community and differentiate active faults from inactive

ones.

Why do we need to learn about

earthquakes?

Where do earthquakes occur?

DAMAGED ROAD

WHAT IS A FAULT?

A BREAK in the Earth’s crust, and along the break, significant movement has taken

place.

HOW DO FAULTS PRODUCE QUAKES??

Energy from inside the Earth make the ground move

(pulling the rubber band).

There is no movement friction right away because

of the FRICTION ( connecting tape). Friction held the rocks

together.

Once the friction is overcome, the ground will move and the earthquake

will occur.

Every time a FAULT slips/

move,The Earth QUAKES.

Where does an earthquake start?

Widescreen Test Pattern (16:9)

Aspect Ratio Test

(Should appear circular)

16x9

4x3

FOCUS/ HYPOCENTER

- start (origin) of the earthquake

- region where rocks break

EPICENTER - The point on Earth’s surface,

above the focus- the most violent shaking of the

ground occurs

Use your model to show different types of movement along a fault. How would the surroundings be

affected?

How are the earthquake waves known?

SEISMIC WAVES

Waves of energy caused by sudden breaking of rock within

the Earth or an explosion.

SEISMOGRAPH

P wave (PRIMARY WAVE)- Fastest seismic wave

S wave ( SECONDARY WAVE)- Slower than P wave.- Do not travel thru liquid

L wave ( SURFACE WAVES)- Travel from focus up to the epicenter-Causes MOST of the damage during an earthquake

Questions:1.When an earthquakes occurs, where would shaking be greater? Near the epicenter or away the epicenter?

2.Where would damage be more? Near the epicenter or away from the epicenter?

3.Where would be the intensity higher? Near the epicenter or away from the epicenter?

Philippine Institute of Volcanology

And Seismology

(PHILVOLCS)

DESCRIBING THE STRENGTH OF AN

EARTHQUAKE

Intensity Scale

Magnitude

Roman Numerals ( I – X)

Hindu –Arabic Numerals

1- 9

PHIVOLCS Earthquake Intensity Scale

How strong is the earthquake?

I. Scarcely Perceptible - Can be felt under favorable circumstances. Delicately balanced objects are disturbed slightly. Still water in containers oscillates slowly.

X. Completely Devastating - Nearly all man-made structures are destroyed. Massive landslides and liquefaction, large scale subsidence, uplift of landforms, many ground fissures are observed. Changes in river courses and destructive seiches in large lakes occur. Many trees are toppled, broken, and uprooted.

DO YOU LIVE NEAR

AN ACTIVE FAULT?

THINGS TO DO:

1. At home before an earthquake

2. Indoors during an earthquake

3. Outdoors during an earthquake

4. After an earthquake

At home before an earthquake:

Prepare an earthquake emergency kit with non- perishable food, bottled

water, flashlights, first aid materials, blankets, spare

glasses and other essential items and store it where it will be easily accessible in

case of earthquake.

Emergency Kit

At home before an earthquake:

Turn off the electricity and water supply.

Anchor heavy furniture down to the floor.

Indoors during an earthquake:

Go to a safe such as under the table or desk, or wall away from windows or hazardous objects.

Cover the back of your head and eyes.

Beware of any falling objects or electrical wires.

If cooking, turn off heating elements ASAP.

Triangle of Life (Indoors)

outdoors during an earthquake:

Stay in open areas away from buildings,

power lines, trees, and other potential hazards.

If driving, stop quickly.

outdoors during an earthquake:

After an earthquake:

After an earthquake:

After an earthquake:

Be ALERT.Keep

ALERT.PRAY.