Continental Drift
What are convection currents?
Molten rock (magma) in the lower part of the mantle is heated by the close proximity to the core. As the magma is heated it rises towards the crust. As the molten rock reaches the upper part of the mantle, it cools down due to distance from the core. As the rock cools it begins to sink back towards the core. This creates a circular current, or a convection cell.
Name the three different directions plates move in
Transform, divergent, convergent
What are the three different modes volcanoes can be in?
Active, dormant, extinct
Active volcanoes have erupted at least once within the last 10,000 years. Dormant volcanoes have not erupted in the last 10,000 years but are expected to erupt again. Extinct volcanoes have not showed any activity since the last ice age and are unlikely to erupt again.
Name 3 volcanic Hazards
Volcanic bomb, Ash cloud, Tephra fall, Acid Rain, Lava Dome, Pyroclastic flow, Lava flow, Lahar, Fumaroles, Volcanic Earthquakes.
What kind of Volcano is Kilaeua in Hawaii?
Shield volcano
List the layers of the earth from outermost to inner most
basic: crust, mantle, outer core, inner core
advanced : Lithosphere, Asthenosphere, Mantle, outer Core and Inner Core.
What are the 4 different ways that plates interact with each other to create landforms
Transform, Constructive, Destructive, Collision
What are the two main eruption types?
Explosive, Effusive
Explosive (loud and big) or Effusive (quiet and gentle).
Describe what a Volcanic bomb is?
a mass of partially molten rock (tephra) larger than 64 mm (2.5 inches) in diameter, formed when a volcano ejects viscous fragments of lava during an eruption
What are the three main stages of a super volcano (caldera) eruption?
Surge of magma, Super eruption, resurgence
Surge of magma: they form DEPRESSIONS within the Earth’s crust. They begin with a column of magma rising through a vent into the Earth’s crust. The magma gets stuck and pools, melting the rock around for thousands of years
Super Eruption: Over thousands of years the pressure builds up and when the eruption eventually happens it drains the magma lake and the land above collapse down over, creating a caldera.
Resurgence: lakes form, plants and wildlife return completely changes the landscape
Name the seven continents
North America, South America, Oceania, Asia, Europe, Africa, Antarctica
What is the most likely natural disaster to happen at a transform plate boundary?
Earthquakes as the plates slide past each other it causes friction and cause earthquakes
What are the three elements that affect what type of eruption will occur?
Gas, Magma type, Water
What is the most deadly Volcanic Hazard? Give an example from a volcano.
Pyroclastic flow: Mt Vesuvius Pompeii entombed the city
Lahar: Pinatubo, 1991-1992 killed 143 people
List 3 economic threats and 3 economic opportunities that can result from an eruption
Threats: Personal property, Commercial property, livestock, transport facilities, recreation facilities, forestry, tourist attractions
Opportunities: Land, geothermal, tourism, Infrastructure, employment, volcanic rock
What evidence is there to back up the theory of continental drift? Give 2 examples
Scientists have found fossils of similar types of plants and animals in rocks of similar age.
How well the continents fit together like jigsaw pieces
Mountain ranges with the same rock types, structures, and ages are now on different sides of oceans
What area of the world is the most volatile? Why is it so volatile?
The ring of fire (it goes through the coasts of South and North America, Asia, and New Zealand) has the most volcanoes in the world. Lots of collision and subduction (destructive zones)
Name 5 features of a Volcano as written in your diagram
Crater. Lava flow. Layers of ash and lava. Steam, gas and dust. Volcanic bomb. Falling ash. Main vent. Secondary vent. Magma chamber
Based on the fact sheet and the hazard map of Mt Ruapehu on the GNS. What is the most likely hazards you would see on Mt Ruapehu when it erupts?
Tephra ranging in size from dust (ashfall) to bombs and blocks, is produced in every eruption. Lava flows occur from the vent (though none in historical times), lava domes in the vent (1945) and fire fountaining (sprays of liquid lava) have been witnessed. Pyroclastic flows are uncommon in Ruapehu’s history with none in historic times. Usually the crater lake causes magma to cool and fragment (explode) quickly and violently leading to fine ash eruptions.
How did the kilauea volcano affect people and property in the short term?
700 homes damaged, highway covered with lava and debris, fissure opened up in the earth
How many plates are there total? Name 5 of the major plates and 3 of the minor plates
15 plates total
7 major
Pacific Plate,North American Plate, Eurasian Plate. African Plate, Antarctic Plate, Indo-Australian Plate, South American Plate.
8 minor:
Juan de Fuca Plate, Cocos Plate, Caribbean Plate, Nazca Plate, Scotia Plate, Arabian Plate, Indian Plate, Philippine Sea Plate.
There are two different ways that you can have a destructive plate boundary. What is the difference between the two? What different landforms are created?
Destructive Oceanic to oceanic plate - creates Oceanic Trench - a depression in the sea floor marking where one plate is forced under the other. Benioff zone - area where plates slide past each other. Volcanic Island Arc - land that has been pushed up by rising magma plumes from the melting subducted plate. Volcanoes follow the ‘arc’ of the trench.
Destructive Oceanic and continental - Volcanic Fold Mountains - The compression of plate due to the collision combined with the rising magma plumes uplifting and forcing their way through vents.
Name all 6 types of volcanoes
Stratovolcano, Lava Dome, Scoria cone, Caldera, Tuff ring, Shield volcano
Based on the fact sheet for lake Taupo on the GNS website what kind of damage will the Volcano do? and what kind of hazards will occur?
Is considered the most powerful eruption known of the last 5000 years globally - it was unusually large compared to most Taupō eruptions. The plume reached a height of 35 - 40 km. Covered parts of the North Island in at least 1 cmof ash. Lakeside areas were covered in tens of metres of pumice and ash pyroclastic deposits. The flow spread up to 90 km from the vent, spreading over all barriers except the upper slopes of Ruapehu.
Describe in detail how a volcano can affect a natural environment use an example from an actual eruption
Kilaeua: The rivers of molten rock left canyon-sized scars on the land. Huge portions of once-green land remain a sea of black. Along the coast, tide pools are now filled with solid rock, part of the nearly 900-acres of new land formed as lava hit the ocean.