SCIENCE LONG TEST 1ST QTR
how active volcanoes, earthquake epicenters, and major mountain belts are distributed
Looking at the positions of most if not all volcanoes, earthquakes, and major mountain belts, they are distributed mainly around the tectonic plate boundaries
Slab pull is the process that results when magma rises at a mid-oceanic ridge and pushes oceanic plates in two different directions away from the ridge.
false
The separation of two continental plates was due to earthquakes from mountain ranges.
false
volcanic activity is a geological event that occurs among the three plate boundaries.
false
. Earthquakes in the circum-Pacific seismic belt
include the M9.5 Great Chilean Earthquake [Valdivia Earthquake] (1960) and the M9.2 Great Alaska Earthquake (1964)
A subduction zone or trench is a long narrow depression in the ocean floor.
true
Heat is the driving force that facilitates the movement of the plates
true
Mountain building happens in continental-continental convergence
true
No volcanoes or mountains are produced in the transform plate boundary.
true
Philippines and Japan also belong to the Pacific Ring of Fire thus, earthquake and volcanic eruptions are usually experienced
true
the Aftermath of taal volcano (1)
The damage extended beyond plant life. Dozens of people perished during the eruption. Large numbers of livestock and pets were also left behind when tens of thousands of people evacuated. Ash even affected the fish—mainly tilapia and milkfish—being raised in thousands of aquaculture pens in Taal Lake. According to the Taal Lake Aquaculture Alliance, Inc., about 30 percent of the fish cages in the lake were destroyed during the eruption. To keep the remaining fish alive, farmers appealed to authorities to allow them to feed and harvest the fish despite lockdowns that prevent people from getting near the still-active volcano. Water has returned to Taal's main crater lake, which mostly evaporated or drained during the eruption
subduction and obduction
Why are earthquake and volcanic belts located in the same area? At converging plate boundaries, two situations are possible.
oceanic crust are sinking
Why do so many earthquakes originate in this region? (Circum-Pacific seismic belt) - The belt exists along boundaries of tectonic plates, where plates of mostly _____________ (or subducting) beneath another plate. Earthquakes in these subduction zones are caused by slip between plates and rupture within plates
the Aftermath of taal volcano
Coffee, rice, corn, cacao, and banana crops were damaged, according to news reports. In one estimate, damages to plants and animals totaled 577 million Philippine pesos, or $11 million. Despite the widespread effects, plants will eventually recover or re-colonize the island—and the layer of new ash will help keep the soil fertile
Which of the following geological processes could have happened when plates have formed mountain ranges?
Collision of continental plates
Continental Rifting
A divergent plate boundary that forms in the middle of a continent.
Whole-Mantle Convection
Also called the plume model Cold lithosphere sinks to the core-mantle boundary and stirs the entire mantle
hotspot
Eruptions at the ___________ create a volcano.
Marianas Trench was formed due to the sinking process created by the collision of two oceanic crusts. Which of the following statements best describes the formation of the Marianas Trench?
Denser Pacific Plate moves beneath the less dense Philippine plate, forming an oceanic trench called Marianas Trench.
converging plate boundary
Much magma is generated at a c __________________ where subduction is occurring. The sinking plate melts as it descends into the asthenosphere; this generates magma, which rises through the other plate to form volcanoes. As it rises, more melting takes place in the rocks it travels through, generating yet more magma
Which of the following geological features will form if two oceanic lithospheres collide?
Oceanic Trench
Which of the following geological processes forms an oceanic trench?
Oceanic trench formed when oceanic plates collide, one subducts under the other.
Which plate boundary is involved in the formation of the Philippine archipelago?
Oceanic-oceanic convergence
Which of the following statements is true about the distribution of earthquakes and active volcanoes?
Most of the active volcanoes and earthquakes are concentrated in the circum-pacific belt.
Which of the following geological features will form if two continental lithospheres collide?
Mountain Ranges
What drives plate motion?
Plate-mantle convection - Mantle plumes extend from mantle-core boundary and cause convection within the mantle - Models • Layering at 660 kilometers • Whole-mantle convection
Rejection of the drift hypothesis
The Great Debate - Main objection to Wegener's proposal was its inability to provide a mechanism
What will happen to the crust if it will move horizontally past each other and in opposite direction?
The crust is neither created nor destroyed.
close proximity
The distribution of the volcanoes, earthquake epicenters, and major mountain belts are distributed in _________________ of the borders of the tectonic plates.
Why do plates move?
The heat from radioactive processes within the Earth's interior causes the plates to move, sometimes toward and sometimes away from each other.
island arc
The line of volcanoes that grows on the upper oceanic plate is an _________
Subduction
The process by which oceanic crust sinks beneath a deep-ocean trench and back into the mantle at a convergent plate boundary. - both volcanoes and earthquakes form where one plate sinks under the other. This process, _____________, takes place because one plate is denser than the other. The denser plate, which invariably has oceanic crust on its top, does the sinking.
Mid-Atlantic Ridge
The third prominent belt follows the submerged __________________. The ridge marks where two tectonic plates are spreading apart (a divergent plate boundary). Most of the mid-Atlantic Ridge is deep underwater and far from human development, but Iceland, which sits directly over the mid-Atlantic Ridge, has experienced earthquakes as large as at least M6.9.
geologic activity
The type of plate boundary and the type of crust found on each side of the boundary determines what sort of ___________ will be found there.
- Oceanic-oceanic convergence ()
Two oceanic slabs converge and one descends beneath the other • Often forms volcanoes on the ocean floor • Volcanic island arc forms as volcanoes emerge from the sea • Examples include the Aleutian, Mariana, and Tonga islands
1. Circum-Pacific seismic belt 2. Alpide earthquake belt 3. Mid-Atlantic Ridge
Where do earthquakes occur? - Earthquakes can strike any location at any time, but history shows they occur in the same general patterns year after year, principally in three large zones of the earth:
Mid-Atlantic Ridge location
a part of the Mid-Atlantic Belt located on the floor of the Atlantic Ocean from Iceland to Antarctica
mountain range
a series of connected mountains that are close together and extend for hundreds or thousands of kilometers (km). - most are located along the plate boundaries where collision of plate occurs. like volcanoes and earthquakes, they are also concentrated in the Circum-Pacific belt. - it surrounds most of Pacific basin.
Mid-Oceanic ridges, volcanoes, and rift valleys are formed in convergent plate boundaries.
false
Circum-Pacific Plate location
stretches from Alaska to Kuril, Japan, Mariana, and the Philippines trenches. it branches toward the Indonesian trench and toward the Kermac-Tonga trench to the northwest of New Zealand.
obduction
the process whereby seafloor sediment becomes attached to the overriding continental plate during subduction. - Second, only earthquakes occur when two plates collide building a mountain range. The density of continental crust is too low for it to subduct, like wood floating on water. Instead, the two plates have a head on collision - building a mountain range.
Characteristics of Tectonic plates
• One plate can carry both continental and oceanic crusts. The average thickness of the lithosphere covered by a continent is 125 km. the average thickness of the lithosphere covered by the oceanic crust is 75 km. • A plate floats on the asthenosphere and slides horizontally over it. It is like a block of ice that float on a lake; it may bend a little or may slightly move up and down. Each plate moves a large solid rock. • Tectonics plates move at very slow rate/ few centimeters per year. Since continents and oceans make up the uppermost part of the lithosphere, both the continents and oceanic crusts move across the Earth simultaneously with the plates
Taal Volcano
An Ash-Damaged Island in the Philippines - March 11, 2020 (covered in entire ash)
Which of the following locations do most of the earthquakes and active and potentially active are found?
Circum-pacific Belt
Transform fault boundaries ()
- Plates slide past one another • No new crust is created or destroyed
Alfred Wegener
A German scientist who proposed the theory of continental drift - - First proposed hypothesis, 1915 - Published The Origin of Continents and Oceans
How did the Aleutian arc island form?
Aleutian arc island was formed when two oceanic plates collide against each other, the denser and therefore heavier of the two subducts beneath the other.
How do the Himalaya Mountain Ranges form?
Himalaya Mountain Ranges was formed due to the collision of the Eurasian plate and Indian plate.
Hotspot volcanoes
Hot mantle plumes breaching the surface in the middle of a tectonic plate - are found in a line. Can you figure out why? Hint: The youngest volcano sits above the hotspot and volcanoes become older with distance from the hotspot.
Which of the types of plate boundaries do most active volcanoes are found?
In both convergent and divergent plate boundary
Which of the following statements best describes plate tectonics?
It is consisting of major and minor plates. They are moving constantly at a very slow rate of 3-5 cm per year. Tectonic plates are like a block of ice floating in the asthenosphere.
How does the volcanic island arc form?
It is formed when two oceanic plates collide against each other, the denser and therefore heavier of the two subducts beneath the other.
mountains
are along CONVERGENT PLATE BOUNDARIES where there pushing of crust without breaking thus forming an elevation, it is also due to piling of pieces of crust as they converge
major mountain belts
are found on places where tectonic plates of pretty much the same density collide, so instead of some of them to go and be subducted, they push against each other and lift the area
Deep-Sea Drilling
drilling that can occur in the depths of the ocean; new oil reserves have been found and the industry has flourished.
Which of the following is the reason why tectonic plates move?
due to thermal convection in the mantle
Alpide earthquake belt
extends from java to sumatra through the Himalayas, the Mediterranean, and out into the Atlantic. This belt accounts for about 17 percent of the world's largest earthquakes, including some of the most destructive
divergent plate boundaries
- Areas where plates move away from each other, forming either mid-oceanic ridges or rift valleys. - Plates move apart at mid-ocean ridges where new seafloor forms. Between the two plates is a rift valley. Lava flows at the surface cool rapidly to become basalt, but deeper in the crust, the magma cools more slowly to form gabbro. So the entire ridge system is made up of igneous rock that is either extrusive or intrusive
Oceanic-continental convergence ()
- Denser oceanic slab sinks into the asthenosphere - Pockets of magma develop and rise - Continental volcanic arc forms - Examples include the Andes, Cascades, and the Sierra Nevadan system
Wegener's continental drift hypothesis
- Evidence used by Wegener • Fit of South America and Africa • Fossils match across the seas • Rock types and structures match • Ancient climates
Convergent plate boundaries (destructive margins)
- Plates collide, an ocean trench forms and lithosphere is subducted into the mantle
Continental drift hypothesis
- Supercontinent called Pangaea began breaking apart about 200 million years ago - Continents "drifted" to present positions - Continents "broke" through the ocean crust
Which of the following statements shows the utilization of advanced concepts in the scientific disciplines to create and implement innovations or workable solutions that improve disaster preparedness?
- UNESCO, in partnership with the University of the Philippines National Institute for Science and Mathematics Education Development (UP NISMED), published a Primer on National Disaster Preparedness and Coping Mechanisms. - In geography, and to a lesser extent sociology and urban and regional planning, there are well-established traditions of hazards and disaster studies, and researchers in these areas have gained disciplinary prominence and intellectual influence. - Social science research plays a critical role in each of these areas, from the development of vulnerability assessment techniques to the determination of effective incentives for risk mitigation and evaluation of effective risk communication.
continental-to-continental convergence
- happens where 2 continental plates collide and push up creating mountain ranges - When two continental plates converge, instead of subduction, the two similar tectonic plates will buckle up to create large mountain ranges like a massive car pile-up. - and geologically creates intense folding and faulting rather than volcanic activity.
Juan de Fuca plate
- is created by seafloor spreading just offshore at the Juan de Fuca Ridge. If the magma at a continental arc is felsic, it may be too viscous (thick) to rise through the crust. The magma will cool slowly to form granite or granodiorite. These large bodies of intrusive igneous rocks are called batholiths, which may someday be uplifted to form a mountain range. -A tectonic plate generated from a mid-ocean ridge and is subducting under the state of Washington.
How can we apply our knowledge and understanding of the distribution of earthquake epicenters and active volcanoes?
-through developing and implementing workable strategies that have a direct bearing on our daily lives and decisions -through improving our disaster preparedness and mitigation -through creating and implementing innovations or workable solutions that improve or preserve life, the environment, disaster preparedness
volcanic islands (also called volcanic arcs)
Along these subduction zones, ________________ form. Examples of these regions include Japan, Indonesia, and the Aleutian Islands
Which among the following mountain ranges above sea level is the longest?
Andes Mountain Ranges
North Anatolian Fault
Another important transform boundary is the ______________________ t in Turkey. This powerful fault last ruptured in 1999 in Izmit, Turkey which killed 17,000 people in 48 seconds.
Which of the following geological features will happen when the plate tectonic moves?
Arc Island Oceanic Trench Rift Valley All of the above
Convergent plate boundaries
Areas where plates move toward each other and collide, causing uplift. - When two plates converge, the result depends on the type of lithosphere the plates are made of. No matter what, smashing two enormous slabs of lithosphere together results in the creation of magma and earthquakes.
Transform plate boundaries:
Areas where two plates grind past each other resulting in faults such as the San Andreas Fault. Earthquakes often occur at fault lines. - occur when two tectonic plates slide (or grind) past parallel to each other
Ring of Fire location
Around the Pacific Ocean's edge - this ring extends to the Andes of South America, Central America, Mexico, the Cascade Mountains of western United States, the Aleutian Islands, Kamchatka, the Kuril Isles, Japan, Philippines, Indonesia, Celebes, Papua New Guinea, the Solomon Islands, New Caledonia, and New Zealand
linear lakes
As divergence occurs, shallow earthquakes can occur along with volcanoes along the rift areas. When the process begins, a valley will develop such as the Great Rift Valley in Africa. Over time that valley can fill up with water creating ___________
PHIVOLCS, PAG-ASA, and other institutes are creating brochures and infographics to better understand the disasters and what to do before, during, and after it. Which of the following best describes the statement?
Creating and implementing innovations or workable solutions that improve or preserve life, the environment, disaster preparedness.
Which of the following geological processes would occur when two oceanic plates diverge?
Earthquake and mid-oceanic ridge
Earthquake belts
Earthquakes occur mainly on the borders of tectonic plates (boundary) - global distribution of earthquakes is similar to that of volcanoes.
Japan
For which country do we locate the most earthquakes? - The whole country is in a very active seismic area, and they have the densest seismic network in the world, so they are able to record many earthquakes
hotspot chains
Geologists use some _______________ to tell the direction and the speed a plate is moving. Hotspot magmas rarely penetrate through thick continental crust. One exception is the Yellowstone hotspot
Testing the Plate Tectonics Model 2
Hot spots and mantle plumes - Caused by rising plumes of mantle material - Volcanoes can form over them (Hawaiian Island chain) - Mantle plumes • Long-lived structures • Some originate at great depth, perhaps at the mantle-core boundary
How did the Philippine Islands form?
It was formed due to the volcanic eruptions that happened million years ago.
Which of the following statements shows understanding, addressing, and resolving issues or problems of the communities within the active volcanoes and earthquake epicenters?
John is conducting a risk assessment in the following areas found in the danger zone and initiating activities such as evacuating the community in a safer zone.
Which of the following statements best describes how Marianas Trench was formed?
Marianas trench was formed due to the subduction of the denser Pacific plate beneath the less dense Philippine plate.
Which of the following geological features is NOT being formed in the convergent plate boundary?
Mid-Oceanic Ridge
Which of the following geological features is being formed in the divergent plate boundary?
Mid-Oceanic Ridge
Which of the following geological features will form if two crustal plates are moving separately?
Mid-Oceanic Ridge
Theory of Plate Tectonics
More encompassing than continental drift • Associated with Earth's rigid outer shell - Called the lithosphere - Consists of several plates • Plates are moving slowly • Largest plate is the Pacific plate • Plates are mostly beneath the ocean
Transform faults
Most join two segments of a mid-ocean ridge • Aid the movement of oceanic crustal material
Ring of Fire
Most of the active volcanoes nowadays are found at the so-called _____________which is practically the border of the Pacific Tectonic Plate. - is a region around much of the rim of the Pacific Ocean where many volcanic eruptions and earthquakes occur. The Ring of Fire is a horseshoe-shaped belt about 40,000 km long and up to about 500 km wide. - part of the CIRCUM-PACIFIC BELT - 70% of the world's earthquakes occur in this region
mountain belt
Mountain ranges and mountain systems in a long connected chain.
Taal Volcano in the Philippines
On January 12, 2020, the _______________ awoke from 43 years of quiet and began to spew gases, ash, and lava into the air. In the days and weeks that followed, the eruption dropped a layer of unusually wet, heavy ash on the surrounding landscape, withering vegetation and turning the lush fields and forests of Volcano Island a ghostly gray
Changing Plates and Plate Boundaries
Plates and boundaries migrate and are created and destroyed • Breakup of Pangaea - Formed a new ocean basin - the Atlantic
continental arc
The volcanoes are known as a ______________. The movement of crust and magma causes earthquakes ( Convergent Plate Boundaries)
Subduction of the Juan de Fuca plate
The volcanoes of northeastern California—Lassen Peak, Mount Shasta, and Medicine Lake volcano—along with the rest of the Cascade Mountains of the Pacific Northwest are the result of __________________ beneath the North American plate
Circum-Pacific seismic belt
The world's greatest earthquake belt, the circum-Pacific seismic belt, is found along the rim of the Pacific Ocean, where about 81 percent of our planet's largest earthquakes occur. It has earned the nickname "Ring of Fire".
Asthenosphere
Theory of Plate Tectonics - Exists beneath the lithosphere - Hotter and weaker than the lithosphere - Allows for the motion of lithosphere
Why do we have to understand, address, and resolve issues or problems of the communities within the active volcanoes and earthquake epicenters?
To create and implement innovations or workable solutions that improve or preserve life, the environment, disaster preparedness.
Faults and earthquakes occur to transform plate boundaries
True
Taal Volcano in the Philippines (1)
Two months later, the ash-damaged landscape still looks more like the Moon than the tropics. On March 11, 2020, the Operational Land Imager (OLI) on Landsat 8 acquired an image of Taal that underscores the consequences of the ashfall. For comparison, the other image shows the same area on December 6, 2019.
Divergent plate boundaries (constructive margins)
Two plates move apart - Mantle material upwells to create new seafloor - Ocean ridges and seafloor spreading • Oceanic ridges develop along well-developed boundaries • Along ridges, seafloor spreading creates new seafloor • Continental rifts form at spreading centers within a continent
Continental-continental convergence ()
When subducting plates contain continental material, two continents collide • Can produce new mountain ranges such as the Himalayas
Indonesia
Which country actually has the most earthquakes? - is in a very active seismic zone, also, but by virtue of its larger size than Japan, it has more total earthquakes.
China and Iran
Which country has the most catastrophic earthquakes, or which has had the most damage and fatalities? - both are in seismically active areas, have very long historical records, and have had many catastrophic earthquakes. Turkey is also worth mentioning in this category
ocean trench
a deep, underwater trough created by one plate subducting under another plate at a convergent plate boundary - marks the location where the plate is pushed down into the mantle.
Divergence continues
a sea can form like the Red Sea and finally an ocean like the Atlantic Ocean. Check out the eastern half of Africa and notice the lakes that look linear. Eastern Africa is tearing apart from these linear lakes, to the Great Rift Valley, and up to the Red Sea. The ultimate divergent boundary is the Atlantic Ocean, which began when Pangea broke apart. (Divergent Plate Boundaries)
volcanic belt
a string of volcanoes created on the overriding continent parallel to a convergent boundary
Earthquakes
are common at mid-ocean ridges since the movement of magma and oceanic crust results in crustal shaking. The vast majority of mid-ocean ridges are located deep below the sea. (Divergent Plate Boundaries)
Most active volcanoes
are found along DIVERGENT PLATE BOUNDARIES that allows magma to go out and push the plates apart, and these are also found along convergent plate boundaries where there is subduction of plate and melts the plate and allows magma to rise
earthquake epicenters
are not found at only some specific place, but they are found everywhere where there's border between two or more tectonic plates, it doesn't matter do they collide, move away from each other, subduct, the earthquakes will be there.
Why does the oceanic crust sink beneath the continental crust at the subduction zone?
because the oceanic crust has a greater density.
Himalaya Mountains in Asia
formed by obduction. - a formed this way, from a collision between the Indian and Asian Plates. At transform plate boundaries, the two plates slide by each other. This generates little volcanic activity (there is no "gap" between the plates) or mountain building. Earthquakes, however, are common.
intraplate activity; hotspot
geologic activity that takes plates within a plate away from plate boundaries - A small amount of geologic activity, known as ____________ does not take place at plate boundaries but within a plate instead. Mantle plumes are pipes of hot rock that rise through the mantle. The release of pressure causes melting near the surface to form a ____________-
plate boundary
is a fracture that separates one place from other plates. Adjacent plates can move relative to one another in three different ways. They can move toward each other and converge and collide, they can split or pull apart, or they can slide horizontally against each other in opposite directions. When plates move, the results are seen along the _______. A change in one may cause others to change. - are the edges where two plates meet. Most geologic activities, including volcanoes, earthquakes, and mountain building, take place.
Pacific ring of fire
is a ring around the Pacific Ocean of subduction zones, which most are oceanic-to-oceanic convergence
San Andreas Fault
most famous transform boundary is the ______________where the Pacific plate that Los Angeles and Hawaii are on is grinding past the North American plate that San Francisco and the rest of the United States is on at the rate of 3 inches a year. Recently, geologists have stated that San Francisco should expect another disastrous earthquake in the next 30 years. A
most earthquakes
occur at TRANSFORM AND CONVERGENT PLATE BOUNDARIES
Subduction ()
occurs along oceanic trenches called subduction zones where lots of intense earthquakes and volcanic eruptions can occur. The denser, subducting plate begins to heat up under extreme pressure near the mantle and melts to create causes melting in the volcanoes. (Convergent Plate Boundaries)
Ocean-to-continent convergence
occurs when oceanic crust converges with continental crust, forcing the denser oceanic plate to plunge beneath the continental plate. (Convergent Plate Boundaries)
oceanic-to-oceanic plate boundary
occurs when two oceanic plates converge, causing the older, denser plate will subduct into the mantle
Mid-Alantic Ridge
rest of the earthquakes occur in diverging plate boundaries such as the ______________ as well as transform plate boundaries. - is a vast chain of underwater mountains on the floor of the Atlantic Ocean. underwater chain of mountains 75, 639 km long. - chain runs down the middle of the Atlantic Ocean (surfacing at Iceland), around Africa, through the Indian Ocean, between Australia and Antarctica, and north through the Pacific ocean, making it the longest mountain range In the whole world.
most destructive earthquakes in Alpide earthquake belt
such as the 2005 M7.6 shock in Pakistan that killed over 80,000 and the 2004 M9.1 Indonesia earthquake, which generated a tsunami that killed over 230,000 people.
continental-to-continental convergence examples
the Himalayan mountains as India is colliding with Asia, the Alps in Europe, and the Appalacian mountains in the United States as the North American plate collided with the African plate when Pangea was forming. The Kashmir India earthquake of 2005 that killed over 80,000 people occurred because of this process. And most recently, the 2008 earthquake in China which killed nearly 85,000 people before the Summer Olympics was because of this tectonic force. The Appalachian Mountains are the remnants of a large mountain range that was created when North America rammed into Eurasia about 250 million years ago.
- Circum-Pacific Belt - Mid-Atlantic Belt - Mid-Continental Belt
three major belts in the world which are frequented by volcanic activities and earthquakes of varying intensifies are the ____________
Mid-Continental Belt
volcanoes are also found in convergent plate boundaries such as the _______________. - includes the volcanoes of the Alps, the Mediterranean Sea like Stromboli, Vesuvius, and Etna; volcanoes of the Aegean Sea, Mt. Ararat (Turkey), Elburz, Hindukush, and the Himalayas. - 20% of the earth's earthquakes have occurred. - extends further to Tibet, the Pamirs, and the mountains of Tien Shan. - the young folded mountain systems of Myanmar, China, and eastern Siberia also fall in this belt.
Hawaiian Islands
were formed by such a hot spot occurring in the middle of the Pacific Plate. While the hot spot itself is fixed, the plate is moving. So, as the plate moved over the hot spot, the string of islands that make up the Hawaiian Island chain were formed
Measuring Plate Motion
• By using hot spot "tracks" like those of the Hawaiian Islands - Emperor Seamount chain • Using space-age technology to directly measure the relative motion of plates - Very Long Baseline Interferometry (VLBI) - Global Positioning System (GPS)
Testing the Plate Tectonics Model 3
• Evidence for the plate tectonics model - Paleomagnetism • Probably the most persuasive evidence • Ancient magnetism preserved in rocks • Paleomagnetic records show - Polar wandering (evidence that continents moved) - Earth's magnetic field reversals • Recorded in rocks as they form at oceanic ridges
Testing the Plate Tectonics Model 1
• Evidence from ocean drilling - Some of the most convincing evidence confirming seafloor spreading has come from drilling directly into ocean-floor sediment • Age of deepest sediments • Thickness of ocean-floor sediments verifies seafloor spreading
What Drives Plate Motions
• No one model explains all facets of plate tectonics • Earth's heat is the key driving force • Several models have been proposed - Slab-pull and ridge-push model • Descending oceanic crust pulls the plate • Elevated ridge system pushes the plate
convergent, divergent, transform
▪ This is because the boundaries push further away, move closer together, and slide against each other _____________ thus creating either mountains, volcanoes, or earthquakes.
