3. MELC: Describe and relate the distribution of
active volcanoes, earthquake epicenters, and major
mountain belts to Plate Tectonic Theory
Objectives:
• 1. Define the following:
• a. Active volcano
• b. earthquake epicenter
• c. Mountain belt
• 2. Explain Tectonic plate Theory
• 3. Relate the distribution of active volcanoes, earthquake epicenters
and mountain belts to Tectonic plate Theory.
4. Plate Tectonics
• Planet Earth may appear solid, but actually it is
constantly changing.
1. Contraction theory – one of the earliest theory
about change in geography. This theory suggest
that as the Earth cooled after its formation, its
surface contracted and wrinkled.
• Wrinkles are now mountain ranges all other
features were relatively static.
5. Plate Tectonics
• 2. Continental drift theory contradicts contraction theory.
• Proposed by Alfred Wegener in 1912
• Pangaea the supercontinent present before time.
• Gondwana& Laurasia are continents produce when Pangaea
spit into two. Those two supercontinent furtherly split into
other continents we know until today.
• Gondwana is composed of Africa, Antarctica, South
America, Australia and subcontinent of India.
6. Plate Tectonics
• Laurasia (northern) includes Asia, Northern
America, Europe.
• The continents move 15 millimeters per year.
• The continental drift theory was rejected by
scientist due to failure in the explanation on what
drives the continents to move.
• 1960’s, approximately 30 years after Alfreg
Wegener’s death, an American geologist Harry
Hess proposed the seafloor spreading theory.
7. Plate Tectonics
• 1960’s, approximately 30 years after Alfred
Wegener’s death, an American geologist Harry
Hess proposed the seafloor spreading theory.
• It proposes that seafloor spread, not the
continents.
• Theory of tectonic plates incorporates
continental drift and seafloor spreading theory.
The lithosphere is composed of continental
plates(made of granitic rocks) and oceanic
plates(made of basaltic rocks).
8. Plate Tectonics
• There are 15 major tectonic plates composed of
7 primary plates and 8 secondary smaller
plates.
a. Primary Plates- The Australian plate, the Pacific
Plate, North American Plate, South American
Plate , African Plate, Antarctic plate.
b. Secondary Plate- Juan de Fuca Plate, Nazca
Plate, Cocos Plate, Caribbean Plate, Philippine
plate, Arabian plate, Indian Plate and Scotia
Plate.
9. Tracing the Ring of Fire
• The pacific ring of fire is susceptible to and very
much frequently by volcanism-related geologic
activities such as volcanic eruption, earthquake,
faulting and tsunamis.
10. Volcanoes
• Volcanoes are formed by subduction. Subduction
is the convergent movement of tectonic plates
where a denser plate is pushed beneath lighter
one.
• Notice that at the edge of Pacific plate(oceanic
tectonic plate in Pacific ocean) there are 452
volcanoes.
11. Earthquake
• Earthquake basically is just shaking of the earth. Most of the
earthquake are present at the edge of the plate boundaries
where Tectonic plates collide.
• During an Earthquake, energy travels through the Earth in
the form of seismic waves(wave present in earth).
• Focus or Hypocenter is the part of the Earth where the
seismic wave is first released.
• Epicenter is the point above the focus found on the crust.
12. Mountains and Mountain ranges
• Mountains are large landforms hat rise well above
the ground and have slopes and a peak, generally
higher than a hill.
• Orogenesis refers to the process of forming
mountains and mountain ranges. It involves the
collision of plates.
• Tectonic plates move toward each other and
form mountain and mountain ranges.
13. Reference(s):
• Ferrioles, J., Ramos, A. C., & Silvero, A. A., Bayquen, A. V.
Exploring life through Science: The new Grade 10. Quezon City:
Phoenix Publishing House.
