Volcanoes:) Flashcards
Name all the plates?
Pacific Plate
Euroasian plate
North American plate
South American plate
Nasca plate
Indo-Australia plate
African plate
Antarctic plate
Indian plate
Two impacts of Volcanic activity
Loss of life 57 people were killed in the mount Saint Helen’s eruption.
Destruction is property. Hawaii 2023 people lost their lives due to volcanic eruptions
Life cycle of a volcano
Active
Dormant
Extinct
Where do Volcanoes happen
Volcanoes happen and Constructive, Destructive plate boundries and hotspots
How do Volcanic eruptions happen?
A volcano is a mountain formes due to the eruption of magma through a hole or vent in the earths surface
Sometimes magma erupts through a long fissure in the earths crust making a flat topped Plateau
Describe a case that you have studied on Volcanoes
A case that I have studied on Volcanos is Mt. St. Helen’s.
Mount St Helens erupted in 1980 its was a lateral eruption and 57 people were killed.
Volcanologists expected it to be a vertical eruption. Mount St Helen’s was 10,000 feet high before the eruption.
What is used to measure the Strenught of Volcanic activity
A VEI used to measure the strength of Volcanic Activity.
How do volcanoes happen
The most violent volcanoes happen at destructive plate boundaries & at hot spots. Before an eruption, magma and gases build up in the magma chamber. When the pressure becomes too great, the volcano erupts through a pipe called a vent, ejecting hot lava, gases, ash and rock fragments. These materials are known as pyroclasts. The top of the volcano can be blown off, the hole left is called a crater. E.g. Mount St. Helens 1980 eruption, Washington State, USA.
Describe how an earthquake takes place
Most major earthquakes happen at destructive plate boundaries. These two plates collide, and over decades pressure builds up at a point call a fault line. When the pressure becomes too great, one plate slips releasing energy known as an earthquake. The point where the energy is released is called the focus. Energy radiates out in all directions, these waves are called shockwaves. Most damage is caused at the epicentre, which is the point on the earth’s surface directly above the focus. When an earthquake occurs under the ocean it can cause a huge wave called a tsunami. E.g. Japan 2011 earthquake and tsunami
Explain how fold mountains occur
Folding occurs at destructive plates boundaries. Great pressure leads to extreme heat. This softens the layers of rock, making them more bendable. Over millions of years in a very slow process the rocks are pushed upwards and folded, creating fold mountains. The upward folds of rock are called anticlines, and downward folds called synclines. An example of fold mountains are the Himalayans where the Indian and Eurasia plates collide.
Explain how tectonic plates move
The core heats the magma in the mantle. The hot magma rises, coming in contact with the crust [plates]. This creates friction which moves the plates. The magma is cooler now as it is farthest from the core. It sinks back to the core where the cycle is repeated. This cycle is called convection currents which results in the plates moving. E.g. the Eurasia and North American plates are moving away from each other due to convection currents.
