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The earth's crust is made up of many tectonic plates which are slowly moving. When two tectonic plates clash, rub, or separate, this can cause an earthquake. A volcano is caused by a build up of magma under the earth's crust.
As stated above the Earth's crust and solid brittle upper mantle together form the lithosphere. This behaves as a brittle solid. This means that when the strength of this layer is exceeded it fractures or breaks apart into separate or discrete blocks. These very large blocks are known as tectonic plates.
The tectonic plates are in motion due to mantle convection and processes known as slab pull and ridge push (controlled by gravity).
Earthquakes:Where these tectonic plates are moving towards each other (a convergent boundary) or sliding past each other (a transform boundary) the rocks forming either side of the boundary can become locked together or "squashed" against each other. The tectonic plates however carry on moving. This causes the rocks to become even more squashed (technically described as increasing strain). This stores energy in the rocks (known as elastic potential energy) and the more the rocks are squashed, the higher the level of energy becomes.At some point the rocks in the crust around the fault zone are no longer able to support the squashing load (more correctly known as compressive stress at convergent boundaries and shear stress at transform boundaries) and the fault slips or a new fracture or fault is formed. This allows all the stored energy to escape in one instant in the form of seismic waves causing an earthquake.
Volcanoes:Volcanoes are often (but not always) caused by the movement of tectonic plates.Volcanism at Convergent Boundaries:
At convergent boundaries where one plate is being pressed against another plate a process known as subduction occurs. This is a process where the more dense plate is forced underneath the less dense plate and down into the earth's mantle.
As the plate descends the temperature increases and "volatiles (mainly water) are forced out of the descending crust into the overlying ho mantle rocks. Water has a very important effect on the hot mantle material - it causes it's melting temperature to decrease. This in turn causes some of the mantle material to melt forming magma (this process is known as partial melting). The high confining pressures (due to the weight of the overlying material) and the lower density of the magma cause it to rise towards Earth's surface. When it reaches the surface it is erupted through fissures or holes known as volcanic vents and other time causes the creation of a volcanic cone. Examples of this sort of volcanism / volcanoes are the volcanoes of the Cascades range in the Western US (e.g. Mt. St. Helens) and the volcanoes of the Andes mountain range on the Western edge of South America.
Volcanism at Divergent Boundaries:
At divergent boundaries the process is a little different! Here two plates are moving away from each other. This causes the lithosphere to become thinner. This in turn reduces the confining pressure in the underlying mantle material but does not reduce it's temperature. The reduction in confining pressure reduces the melting temperature and so causes partial melting to occur creating magma. This in turn erupts at the surface. This sort of volcanism occurs at Mid-Ocean-Ridges (such as the Mid-Atlantic-Ridge) or continental rift zones (such as the East African Rift valley).
Intraplate Hotspot Volcanism:
A final type of volcanism is caused by "hotspots" in the upper mantle. These are zones where the mantle material is at a much higher temperature than normal which causes melting and the formation of magma. This high temperature zone is thought to be caused by upwelling plumes of hot material from deep within the mantle (some geophysicists think they form as far down as the core-mantle boundary). These are known as mantle plumes however there is some debate about their exact nature currently occurring within the geophysical community.
The volcanoes that are caused by mantle hotspots are unusual in that they can form within the centres of tectonic plates whereas the majority of volcanism described above occurs at or near tectonic plate boundaries. A very good example of volcanism caused by mantle hotspots are the volcanic islands that form the Hawaiian Island chain.
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What else can I help you with?
How many earthquakes and volcanoes occur along the Ring of Fire each year?
Approximately 90% of the world's earthquakes and 75% of active volcanoes occur along the Ring of Fire each year. This region encircles the Pacific Ocean and is known for its seismic and volcanic activity due to tectonic plate boundaries.
What type of earthquake occur in Hawaii?
Most earthquakes in Hawaii are caused by the movement of the Pacific Plate beneath the islands. These earthquakes are typically shallow and occur on fault lines in the Earth's crust. The seismic activity in Hawaii is predominantly due to volcanic activity and not tectonic plate movements.
Earthquakes and volcanoes occur at plate boundaries is true?
Yes, earthquakes and volcanoes commonly occur at plate boundaries due to the movement and interaction of tectonic plates. At convergent boundaries, one plate is forced below the other, leading to earthquakes and volcanic activity. At divergent boundaries, plates move apart, creating fissures where magma can rise to the surface. Transform boundaries, where plates slide past each other, can also produce earthquakes.
What are the two kinds of earthquake and be able to differentiate?
The two main types of earthquakes are tectonic and volcanic. Tectonic earthquakes occur along fault lines when tectonic plates move. Volcanic earthquakes occur near volcanoes due to the movement of magma beneath the surface. Tectonic earthquakes are more common and are caused by the Earth's tectonic plates shifting, while volcanic earthquakes are associated with volcanic activity.
What geological hazards are on the pacific plate?
On the Pacific Plate, geological hazards include earthquakes due to its boundary with other tectonic plates, volcanic activity along the Ring of Fire, and tsunamis generated by subduction zones and underwater landslides. These hazards make the Pacific Plate one of the most seismically active regions in the world.
Do volcanoes occur in oceans and earthquakes occur on land?
Earthquakes and volcanoes both occur in land and ocean. =)
Volcanoes and earthquakes are likely to occur?
Yes, they are likely to occur.
Earthquakes and occur at plate boundaries?
Volcanoes
Why do earthquakes occur at volcanoes?
To release pressure.
What are volcanoes and earthquakes likely to occur?
If you mean "where" earthquakes and volcanoes are most likely to occur it is in what's called the "ring of fire" which is the coastal ring around the Pacific Ocean.
Why do volcanoes and earthquakes occur on plate boundries?
earthquakes occur because plates move and they over lap causing an earthquake.
What energy transfers occur in volcanoes and earthquakes?
by killing people
Where do earthquakes and volcanoes commonly occur?
Along fault lines
Where are earthquakes or volcanoes likely to occur?
Earthquakes are likely to occur along tectonic plate boundaries where there is movement and stress in the Earth's crust. Volcanoes are likely to occur at convergent plate boundaries, divergent plate boundaries, and hotspots where magma from the Earth's mantle reaches the surface.
Where volcanoes and earthquakes occur?
Anywhere where the earths plates meet. Earthquakes occur only were there is an epicenter. Were ever the epicenter is the earthquake will happen.
Why are volcanoes and earthquakes found together?
The majority of earth's volcanoes and earthquakes occur near the boundaries of tectonic plates. Therefore, an area that has volcanoes is likely to be prone to earthquake as well.
Do volcanic eruptions and earthquakes occur ONLY at the boundaries?
No. Volcanoes can be found at hot spots away from plate boundaries. These volcanoes can produce earthquakes. Earthquakes can also occur at areas of ancient geologic activty such as failed rifts and can occur as a result fo glacier retreating.
