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.
Tension [pic] d. Compression 6. What is Earth's core composed of? [pic] a. hydrogen and iron b. magnesium and silicon [pic] c. iron and nickel d. nickel and silicon 7. A large ocean wave that is generated by vertical motions of the seafloor during an earthquake is called a(n) __________. a. upwelling current b. seiche [pic] c. tsunami d. tidal range 8.
There is a convergent boundary on the west side of the United States. At a convergent boundary, two plates collide, and the denser plate is subducted. Volcanoes and earthquakes are common as a result of pressure and friction. There is also a transform boundary forming the San Andreas Fault which is between an oceanic plate subducting under a continental plate. 3.
Discuss the view that the impact of the earthquake hazards depends primarily on human factors? An earthquake, a sudden violent shaking of the ground can be caused by a number of things from seismic activity and resulting in varying impacts. The cause of an earthquake are a result of built up pressure under the earth’s crust, the pressure comes from the movement of the tectonic plates, they can occur on any plate boundaries. Although the majority of the earthquake hazards come from the physical factors, human factors can determine the severity of the event. The impacts created from an earthquake can come from the physical factors of the size, the location of the epicentre and the surrounding areas such as a ground type and the lithology of the rocks.
Due to high temperatures in the mantle of around 3000 degrees centigrade, this oceanic crusts melts and then rises due to the convection currents in the aesthenosphere . As it joins with trapped seawater and sediment, it melts the overlying continental crust, and the magma plumes rise to the surface. They contain more silica so are more viscous, which plugs up the volcano, meaning pressure build up. This is why these volcanoes are so explosive. Another type of plate boundary are constructive, which is the margin between two diverging plates where new magma
'The extent to which volcanic processes represent hazards depends on where and when they occur.' Discuss this statement. Volcanic processes become a hazard when they impact upon the human and built environments, killing and injuring people, burying and collapsing buildings, destroying infrastructure and bringing agricultural activities to a halt. Volcanic hazards are influenced by several factors including location, time and frequency of eruptions, and the materials ejected. It is the viscosity of magma that largely determines the nature and power of an eruption and the resultant severity of the hazard.
G208: Volcanoes Chapter 7 : Kilauea, Hawaii 1. What is "volcanic tremor"? (page 94, para 2 to page 95) A volcanic tremor is a continuous, low-frequency vibration of the ground. 2. What do earthquake swarms indicate?
a. Volcano: include the type of lava, where magma is derived, and why this setting produces hazards b. Earthquake: magnitude and amount of displacement or offset 6. Describe the type of hazards in terms of cause, hazard definition, and location (example-tsunami inundation occurred within 1 mile of coastline in low lying areas). 7. Fatalities 8. Damage: 2-3 specific examples of structural damage (earthquakes); areas covered with volcanic debris (volcanic eruption); any other types of damage 9.
This knowledge of plate margins and their movement against one another can help us to understand the distribution of seismic and volcanic events and this is because the majority of events are associated at these plate margins. Wegener’s theory of plate tectonics suggests that all the continents were once joined together in a super continent called Pangea and have since drifted apart due to plate tectonics. To add to this, Sea floor spreading was discovered showing that rock is being created and destroyed, leading us to believe in the existence of plates and plate boundaries. Wegener gained evidence from paleo magnetism and suggested that there were numerous reasons and pieces of evidence for the continents drifting apart. Biologically, there was evidence that proved his theory for example, the Mesosaurus reptile fossils were only found in Africa and South America, proving his ‘jig-saw’ fit idea.
Earthquakes Sheila Fangmeier GEO101 – Earth Science Colorado State University – Global Campus Karen Stelly October 5, 2014 Earthquakes “An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves” (Earthquake, 2014). Seisometers measure earthquake magnitude and intensity based on two scales, the Richter and Mercalli. An earthquake’s magnitude can range from less than 2.0 to greater than 9.0 on the Richter scale and its intensity I to greater than VIII on Mercalli (Richter magnitude scale, 2014). The depth focus is important to how much damage can occur on the Earth’s surface. An earthquake’s depth can be considered shallow (less than 70km), intermediate (between 70km and 300km), or deep (300km to 700km) (Earthquake, 2014).