Download Forces that Shape Earth

Nitty Gritty Science, LLC ©2014
Editable Notes:
Interactive “Notebook”
Style
(scroll down for text only)
Nitty Gritty Science, LLC ©2014
Question: Can Earth be stressed out?
FORCES THAT SHAPE EARTH
Continental crust constantly changes over time due to plate
tectonics. Forces at plate boundaries are strong enough to break
rocks or change their shape.
Stress – force that acts on rock to change its shape or volume; adds
potential, or stored energy, to rock until it changes shape or breaks
Three different kinds of stress can occur in the crust:
 Tension – pulls on the crust, stretching rock so it becomes
thinner in the middle
 Compression – squeezes rock until it folds or breaks
 Shearing – pushes a mass of rock in two opposite directions
Strain – a change in the shape of a rock caused by stress; two types:
 Elastic strain – change in rock that is NOT permanent; when
stress is removed rock goes back to original shape
 Plastic strain – creates a permanent change in the shape of a
rock; usually occurs when rocks are weak or hot
Each type of stress mentioned above produces different landforms:
Landforms Created by Compression
 Mountain ranges – collision between two continental plates
 Ocean trenches – one plate goes under another during
collision forming a deep trench where the two plates meet
 Volcanic arcs – curved line of volcanoes that forms parallel
to plate boundaries
Landforms Created by Tension
 Mid-ocean ridges – tension causes oceanic crust to spread
allowing hot rock from mantle to rise creating high ridges
 Continental rifts – when divergent boundaries occur within
a continent, they cause enormous splits in the crust
Landforms Created by Shearing
 Transform faults – when plates slide horizontally past each
other they form a fault, or a break in the rock of the crust
 Fault zones – an area of many fractured pieces of crust along
a large fault
Nitty Gritty Science, LLC ©2014
Question: How do scientists locate the epicenter of an earthquake?
EARTHQUAKES
Earthquake – vibrations in the ground that result from movement
along faults, or breaks in Earth’s lithosphere
Three types of faults:
 normal fault – form when forces pull rocks apart along a
divergent plate boundary; block of rock above fault moves down
 strike-slip fault – two blocks of rock slide horizontally past
each other in opposite directions
 reverse fault – force pushes two blocks of rock together with
the rock above the fault moving up
focus – point beneath Earth’s surface where rock under stress
breaks to cause an earthquake
epicenter – point on the surface directly above the focus
seismic waves – waves that carry energy of an earthquake away
from the focus; there are three types:
 Primary waves (P waves) – compression waves that travel
through solids and liquids, compressing and expanding the
material they pass through, temporarily changing volume
 Secondary waves (S waves) – only travel through solids and
temporarily change the shape, but not the volume of the
material they pass through; move slower than P waves
 Surface waves – move slower than P and S waves, but can
produce severe ground movement with a wavelike motion
Locating an earthquake’s epicenter is done using triangulating data from
at least three different seismometers, or devices that measure and record
ground motion and helps determine the distance seismic waves travel.
1. Find the arrival time difference between the first P-wave and
S-wave which is called lag time.
2. Find the distance to the epicenter by using a graph of lag time vs.
distance, then go from y-axis to line and read down to x-axis
3. Locate the epicenter by using a map scale to mark radius on a
compass then draw a circle around each seismometer location to
find intersecting point.
Nitty Gritty Science, LLC ©2014
Question: What happens when a volcano erupts?
VOLCANOES
Volcano – weak spot in Earth’s crust where molten material, or
magma, comes to the surface
magma – molten mixture of rock-forming substances, gases and
water from the mantle; when magma reaches Earth’s surface it is
called lava
At plate boundaries the crust often fractures due to the diverging
(pulling) or converging (pushing) plates. As a result, these
fractures allow magma to reach the surface forming volcanic belts
along the boundaries of Earth’s plates.
One major belt is the Ring of Fire, formed by many volcanoes that
rim the Pacific Ocean.
island arc – string of islands created by volcanoes near boundaries
where two oceanic plates collide and one sinks beneath the other
hot spot – area where material from deep within the mantle rises
then melts, forming magma; a volcano forms above a hot spot when
magma erupts through the crust (ex. Hawaiian Islands)
Inside a volcano is a system of passageways through which magma
move. This system includes a magma chamber, pipe, vent, lava
flows and a crater.
Geologists classify volcanic eruptions as quiet or explosive:

quiet eruption – magma has low silica content, flows easily and
erupts quietly with gases bubbling out gently and lava oozing
quietly producing both pahoehoe (fast moving hot lava) and aa
(lava that is cooler and slower-moving)

explosive eruption – has magma high in silica with trapped gases
building up pressure until they explode with incredible force
creating a pyroclastic flow, or an eruption that hurls out ash,
cinders and magma bombs.
dormant volcano – not active, but may become active
extinct volcano – unlikely to erupt again
Nitty Gritty Science, LLC ©2014
Question: After a volcano, what material makes certain landforms?
VOLCANIC LANDFORMS
Volcanic eruptions create many landforms as in the following:
Landforms From Lava and Ash
1. Shield volcano – lava flows out gradually building a wide, gently
sloping mountain
2. Cinder cone volcano – when lava has high viscosity it produces
ash, cinders and bombs which all build up around the vent in a
steep, cone-shaped hill or small mountain
3. Composite volcano – tall, cone-shaped mountains in which layers
of lava alternate with layers of ash
4. Lava plateaus – high, level area that has been built up over time
from lava seeping out of several cracks then traveling a distance
before cooling and solidifying.
5. Caldera – huge hole left by the collapse of a volcanic mountain
Landforms From Magma
1. Volcanic necks – forms when magma hardens in a volcano’s pipe;
softer rock around pipe wears away exposing hard rock
2. Dikes – formed when magma forces itself across rock layers and
hardens
3. Sill – formed when magma squeezes between horizontal layers
of rock
4. Batholiths – mass of rock formed when a large body of magma
cools inside the crust
5. Dome mountain – forms when an uplift pushes a batholith or
smaller body of hardened magma toward the surface
Geothermal Activity
geothermal activity – occurs when magma, a few kilometers,
beneath Earth’s surface, heats underground water and forms:
1. Hot springs – formed when groundwater is heated by a nearby
body of magma or hot rock and eventually rises to the surface to
collect in a natural pool
2. Geyser – fountain of water and steam that erupts from the
ground when buildup of pressure is released
*Water heated by magma can provide an energy source called geothermal energy which can heat homes and make electricity
Nitty Gritty Science, LLC ©2014
Editable Notes:
Text Only
Nitty Gritty Science, LLC ©2014
Question: Can Earth be stressed out?
FORCES THAT SHAPE EARTH
Continental crust constantly changes over time due to plate tectonics. Forces at plate
boundaries are strong enough to break rocks or change their shape.
Stress – force that acts on rock to change its shape or volume; adds potential, or stored
energy, to rock until it changes shape or breaks
Three different kinds of stress can occur in the crust:



Tension – pulls on the crust, stretching rock so it becomes thinner in the middle
Compression – squeezes rock until it folds or breaks
Shearing – pushes a mass of rock in two opposite directions
Strain – a change in the shape of a rock caused by stress; two types:


Elastic strain – change in rock that is NOT permanent; when stress is removed
rock goes back to original shape
Plastic strain – creates a permanent change in the shape of a rock; usually occurs
when rocks are weak or hot
Each type of stress mentioned above produces different landforms:
Landforms Created by Compression



Mountain ranges – collision between two continental plates
Ocean trenches – one plate goes under another during collision forming a deep
trench where the two plates meet
Volcanic arcs – curved line of volcanoes that forms parallel to plate boundaries
Landforms Created by Tension


Mid-ocean ridges – tension causes oceanic crust to spread allowing hot rock from
mantle to rise creating high ridges
Continental rifts – when divergent boundaries occur within a continent, they
cause enormous splits in the crust
Landforms Created by Shearing


Transform faults – when plates slide horizontally past each other they form a
fault, or a break in the rock of the crust
Fault zones – an area of many fractured pieces of crust along a large fault
Nitty Gritty Science, LLC ©2014
Question: How do scientists locate the epicenter of an earthquake?
EARTHQUAKES
Earthquake – vibrations in the ground that result from movement along faults, or
breaks in Earth’s lithosphere
Three types of faults:



normal fault – form when forces pull rocks apart along a divergent plate
boundary; block of rock above fault moves down
strike-slip fault – two blocks of rock slide horizontally past each other in opposite
directions
reverse fault – force pushes two blocks of rock together with the rock above the
fault moving up
focus – point beneath Earth’s surface where rock under stress breaks to cause an
earthquake epicenter – point on the surface directly above the focus
seismic waves – waves that carry energy of an earthquake away from the focus; there
are three types:



Primary waves (P waves) – compression waves that travel through solids and
liquids, compressing and expanding the material they pass through, temporarily
changing volume•
Secondary waves (S waves) – only travel through solids and temporarily change
the shape, but not the volume of the material they pass through; move slower than
P waves
Surface waves – move slower than P and S waves, but can produce severe ground
movement with a wavelike motion
Locating an earthquake’s epicenter is done using triangulating data from at least three
different seismometers, or devices that measure and record ground motion and helps
determine the distance seismic waves travel.
1. Find the arrival time difference between the first P-wave and S-wave which is called
lag time.
2. Find the distance to the epicenter by using a graph of lag time vs. distance, then go
from y-axis to line and read down to x-axis
3. Locate the epicenter by using a map scale to mark radius on a compass then draw a
circle around each seismometer location to find intersecting point.
Nitty Gritty Science, LLC ©2014
Question: What happens when a volcano erupts?
VOLCANOES
Volcano – weak spot in Earth’s crust where molten material, or magma, comes to the
surface
magma – molten mixture of rock-forming substances, gases and water from the mantle;
when magma reaches Earth’s surface it is called lava
At plate boundaries the crust often fractures due to the diverging (pulling) or
converging (pushing) plates. As a result, these fractures allow magma to reach the
surface forming volcanic belts along the boundaries of Earth’s plates.
One major belt is the Ring of Fire, formed by many volcanoes that rim the Pacific Ocean.
island arc – string of islands created by volcanoes near boundaries where two oceanic
plates collide and one sinks beneath the other
hot spot – area where material from deep within the mantle rises then melts, forming
magma; a volcano forms above a hot spot when magma erupts through the crust (ex.
Hawaiian Islands)
Inside a volcano is a system of passageways through which magma move. This system
includes a magma chamber, pipe, vent, lava flows and a crater.
Geologists classify volcanic eruptions as quiet or explosive:


quiet eruption – magma has low silica content, flows easily and erupts quietly with
gases bubbling out gently and lava oozing quietly producing both pahoehoe (fast
moving hot lava) and aa (lava that is cooler and slower-moving)
explosive eruption – has magma high in silica with trapped gases building up
pressure until they explode with incredible force creating a pyroclastic flow, or an
eruption that hurls out ash, cinders and magma bombs.
dormant volcano – not active, but may become active
extinct volcano – unlikely to erupt again
Nitty Gritty Science, LLC ©2014
Question: After a volcano, what material makes certain landforms?
VOLCANIC LANDFORMS
Volcanic eruptions create many landforms as in the following:
Landforms From Lava and Ash
1. Shield volcano – lava flows out gradually building a wide, gently sloping mountain
2. Cinder cone volcano – when lava has high viscosity it produces ash, cinders and bombs
which all build up around the vent in a steep, cone-shaped hill or small mountain
3. Composite volcano – tall, cone-shaped mountains in which layers of lava alternate
with layers of ash
4. Lava plateaus – high, level area that has been built up over time from lava seeping out
of several cracks then traveling a distance before cooling and solidifying.
5. Caldera – huge hole left by the collapse of a volcanic mountain
Landforms From Magma
1. Volcanic necks – forms when magma hardens in a volcano’s pipe; softer rock around
pipe wears away exposing hard rock
2. Dikes – formed when magma forces itself across rock layers and hardens
3. Sill – formed when magma squeezes between horizontal layers of rock
4. Batholiths – mass of rock formed when a large body of magma cools inside the crust
5. Dome mountain – forms when an uplift pushes a batholith or smaller body of
hardened magma toward the surface
Geothermal Activity
geothermal activity – occurs when magma, a few kilometers, beneath Earth’s surface,
heats underground water and forms:
1. Hot springs – formed when groundwater is heated by a nearby body of magma or hot
rock and eventually rises to the surface to collect in a natural pool
2. Geyser – fountain of water and steam that erupts from the ground when buildup of
pressure is released
*Water heated by magma can provide an energy source called geothermal energy which
can heat homes and make electricity
Nitty Gritty Science, LLC ©2014
These notes pair perfectly with my Earth Science
Interactive Notebook: Forces That Shape the Earth:
Want MORE Science Interactive Notebooks?? Check out these
best-sellers from Nitty Gritty Science:
Nitty Gritty Science, LLC ©2014
Copyright Information
© 2014 Erica L Colón: Nitty Gritty Science, LLC. All rights
reserved by the author.
My terms for use for all products available are as follows:
Purchase of this unit entitles the purchaser the right to
reproduce the pages in limited quantities for classroom
use only. Duplication for an entire school, an entire school
system, or commercial purposes is strictly forbidden
without written permission from the author: Erica Colón:
[email protected] or by purchasing multiple licenses.
Copying any part of this product and placing it on the internet in any form (even a
personal/classroom website) is strictly forbidden and is a violation of the Digital
Millennium Copyright Act (DMCA). You may post pictures from using this product in
your classroom as long as you provide a link back to my store.
For more Nitty Gritty Science check out my blog:
[email protected]
or swing by my page on Facebook:
www.Facebook.com/NittyGrittyScience
Special Thanks:
Cover Graphics: Design by Nedti, www.nedti.etsy.com
Cover font title: KG Fonts (Kimberly Geswein Fonts)
Nitty Gritty Science, LLC ©2014