2. Lava Flows is the lava that slide down the side of the volcano. The dangers of hot lava meeting the surface are streams that resulted from the boiling of the salt water and the instantaneously change to a crystal. The water temperature where lava meets water is 30 -69. Volcanic Gases 1.
At destructive plate margins, the oceanic plate goes under the continental plate due to it’s more dense, which is a process known as subduction. The oceanic plate moves down into the mantle entre the benioff zone where it’s melted and destroyed because a pool of magma formed. The magma then rises through the cracks in the crust called vents and it erupts on the surface forming a volcano. There are also different types of volcano for examples composite volcanoes, shield volcanoes and dome volcanoes. For constructive plate margins, the magma rises up into the gap that created by the plate move apart to form a volcano.
As it traverses, due to convection currents, the tectonic plates are dragged along the entire length of the Californian coast. Both plates are moving in a north westerly direction, however, the Pacific Plate is moving faster than the North American Plate, so the relative movement of the North American Plate is to the south east. The Pacific Plate is being moved north west due to sea floor spreading from the East Pacific Rise (divergent margin) in the Gulf of California. The North American Plate is being pushed west and North West due to sea floor spreading from the Mid Atlantic Ridge (divergent margin). The difference in pace and movement of plates, triggers the up build friction.
This type of magma is dangerous because it has a tendency to plug the volcano, trapping gasses which build pressure and eventually erupting violently! This is evidenced in subduction volcano's like Mt. St. Helens and Krakatoa are common types of these volcano's. The magma plugs the volcano which creates and increase in pressure and latent heat which eventually creates a huge explosion. They release enormous amounts of energy and create eruption columns of gas and ash that can rise up to 50 km (35 miles) high at speeds of hundreds of meters per second.
Discuss the view that the impact of earthquake hazards depends primarily on human factors  An earthquake is a tremor or shockwave in the earth’s crust that is caused by the sudden movement of the crust, resulting in the earth shaking. Most earthquakes are a consequence of tectonic plate movement by tension causing a sudden release of energy or rubbing. These normally occur at plate margins or along fault lines and can cause hazards which need to be prevented where possible. Earthquakes can therefore occur at all plate boundaries, destructive, constructive and conservative but the most damaging tend to happen at destructive margins where the earthquakes have a high magnitude due to the rubbing of the oceanic and continental crusts. A hazard is a natural event that has the potential to effect both life and property.
Evidence of sea floor spreading can be found in the Atlantic, where it is believed that the North American and Eurasian plates are moving apart at a constructive plate margin. New land has been created due to the magma rising through a rift and cooling quickly on the surface, also creating a ridge of volcanoes called the Mid-Atlantic ridge. The
Seismicity (or earthquakes) is the shaking of the earth and it is strongly associated with the theory of plate tectonics. Most earthquakes are found on plate margins which are the boundaries between plates. Only 5% of earthquakes that happen every day are not located on plate margins. It has been suggested that human activity could be responsible for some minor earthquakes which do not occur on plate boundaries, for example, the building of large reservoirs puts pressure on the surface of rocks. However despite this, as 95% of earthquakes occur on plate boundaries there must be some kind of link between the two and plate tectonic theory can explain this.
GCSE Geography Explain the process which leads to the development of one landform at a destructive plate boundary (6 marks). A destructive plate margin is an area where two plates are moving towards each other. The point where the two plates meet is called the subduction zone, where one plate is forced down under the other into the mantle. The subducted plate is cooler and denser than the surrounding mantle and gravity pulls it down. Along the coast of south America, the Nazca plate is moving towards the south American plate.
If the redeposit particles are bound together by compaction or | |cementation (formation of new secondary minerals in the spaces between the loose particles), sedimentary rocks are formed. In | |regions where the Earth’s interior temperature and pressure are high enough to change the chemical composition and mineralogy of | |buried igneous or sedimentary rocks, without completely melting them, metamorphic rocks are formed. Distinct groups or assemblages | |of minerals are typically associated with the formation of each of the three major rock types—igneous, sedimentary, and metamorphic| |rocks. Plate tectonics play a major role in the processes of mineral and rock formation. In geologic terms, a plate is a large, | |“rigid” slab of solid rock.
There are three main stages to consider when managing a volcano: before the eruption, during its critical period and evacuation. By planning and being prepared it is possible to reduce the impact volcanic eruptions have on the lives of humans. However, it is very difficult to manage the impacts of volcanic eruptions directly because of the sheer force and unpredictability of volcanoes. Therefore, it is only to a small extent that preparedness and planning can mitigate the effects of volcanic hazards. Preparedness and planning is vital to aid the mitigation of volcanic hazards before an eruption.