Post on 13-Jan-2016
transcript
Earth’s Structure,Earthquakes and Volcanoes
Review
What does the surface of the Earth look like?
• The outermost layer of the earth is called the crust.
• · The mantle is the layer of the earth that lies just beneath the crust, it is the thickest.
• · The crust and the top of the mantle form the lithosphere.
• · The lithosphere is broken into many large pieces of earth, or lithospheric plates, that are always moving.
• · Lithospheric plates = Tectonic plates
Layers of the Earth
• Crust, Mantle, Outer core, Inner core
• The Earth’s inner core is mad up of dense, solid metal.
• The Earth’s lithosphere is the part of the earth that contains plates.
• The Mantle is the thickest of the Earth’s layers.
Earthquakes - Seismic Waves
• Seismic waves known as S and P waves
• P Waves are known as Primary waves
• S Waves are known as Secondary Waves
• Both waves leave at the same time, but P waves arrive first.
P Waves
• Primary
• Push and pull
• Compressional waves
• Travels fast
• Wave travels parallel to the direction of the wave
• Can travel through water
S Waves
• Known as secondary waves
• side to side
• transverse waves
• travels slow
• wave travels perpendicular to the direction of the wave
• Cannot travel through water
Rating System
• Richter Scale – measures total energy released
• Mercalli Scale - measures damage
Epicenter and Focus
• The point beneath the earth’s surface where rock breaks and triggers an earthquake is called the FOCUS.
• The point on the Earth’s surface that is directly above the focus is called the EPICENTER.
Force causes Stress
• Stress occurs when force acts on rock to change its shape or volume.
Body and Surface Waves
• Body Waves – Occur inside the earth and are known as Primary and Secondary waves (S and P)
• Surface Waves - Occur on the surface. Two types - Love and Rayleigh
Aftershock
• An aftershock can cause damage weeks or months after a large earthquake
Volcanoes
• Most volcanoes are found along mid-ocean ridges and where a plate is subducted.
Oceanic to Oceanic
and Oceanic to Continental
Detection
• When geologists detect many small earthquakes in the area near a volcano, the volcano is most likely about to erupt.
Magma and Lava
• Magma is molten material inside the volcano.
• Lava is molten material found outside the volcano.
Types of Volcanoes
Volcano Formation
• Cinder Volcano – are formed by lava fragments called cinders are blown from a single vent and accumulate around the volcano.
• Composite Volcano – are formed by alternating layers of lava and rock fragments. This is the reason they are called composite.
• Shield Volcano – are built by many layers of runny lava flows. Lava spills out of a central vent or group of vents. A broad shaped, gently sloping cone is formed.
Plate Boundaries
• Diverging Plate Boundaries – Plates that move or pull apart from one another.
HINT: divide
• Converging Plate Boundaries – Plates that collide such as oceanic to oceanic or oceanic to continental. Where the heavier or more dense plates slides under the other plate.
HINT: Come together
Additional Info
• Caldera is a huge hole left by the collapse of a volcanic mountain.
• Volcanic ash is made up of fine, rocky particles as small as a speck of dust, but can be very hazardous.
• Lava Flows are the main hazard from a quiet volcanic eruption.
Earth’s Interior
• Oceanic Crust – The outermost layer of Earth’s lithosphere that is found under the ocean. The oceanic crust is made of Basalt.
• Continental Crust – The outermost layer of the Earth’s surface found on land. The continental crust is thicker and made up of granite.
• Lithosphere – The layer of the earth that is made up of part crust and part mantle.
Good LuckKiddos!!