earthquakes
DESCRIPTION
Grade 8 Unit 2 Module 1TRANSCRIPT
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.