Earthquakes occur along fault lines , cracks in Earth’s crust where tectonic plates meet. They occur where plates are subducting, spreading, slipping, or colliding. As the plates grind together, they get stuck and pressure builds up. Finally, the pressure between the plates is so great that they break loose.
How does the theory of plate tectonics help to explain the locations of earthquakes volcanoes and mountain ranges?
The theory of plate tectonics describes the motion of Earth’s plates and their role in geological processes, such as mountain building, earthquakes, and volcanoes. ... When two continental plates converge, neither is subducted. Rather, the crust is uplifted to form towering mountain ranges , such as the Himalayas.
How does the theory of plate tectonics explain volcanoes?
On land, volcanoes form when one tectonic plate moves under another . Usually a thin, heavy oceanic plate subducts, or moves under, a thicker continental plate. ... When enough magma builds up in the magma chamber, it forces its way up to the surface and erupts, often causing volcanic eruptions.
Why does the plate tectonics theory explain volcanoes and earthquakes?
The Earth’s surface is active according to tectonic theory, moving as much as 1-2 inches a year. The many tectonic plates shift and interact all the time. This motion reshapes the Earth’s outer layer. Earthquakes, volcanoes and mountains are the result of this process.
How do earthquake patterns support the theory of plate tectonics?
When scientist mapped out earthquake patterns around the world, they discovered that the location of earthquakes were associated with the locations of the subduction zones . This further provided evidence for plate tectonics.
What are the three theories of plate tectonics?
Plates interact at three types of plate boundaries: divergent, convergent and transform . Most of the Earth’s geologic activity takes place at plate boundaries. At a divergent boundary, volcanic activity produces a mid ocean ridge and small earthquakes.
What new information led to the theory of plate tectonics?
During the war, the latest radar technology was used to map the seafloor . Rapidly, evidence pointing to the process of seafloor spreading and effective plate motion was accumulated. After the war, marine geology was developed, which led to the discovery of the subduction process under the continental margins.
Why do tectonic plates move?
The plates can be thought of like pieces of a cracked shell that rest on the hot, molten rock of Earth’s mantle and fit snugly against one another. The heat from radioactive processes within the planet’s interior causes the plates to move, sometimes toward and sometimes away from each other.
What is the theory of plate tectonics?
The theory of plate tectonics states that the Earth’s solid outer crust, the lithosphere, is separated into plates that move over the asthenosphere, the molten upper portion of the mantle. ... Each type of plate boundary generates distinct geologic processes and landforms.
How fast do tectonic plates move?
They can move at rates of up to four inches (10 centimeters) per year , but most move much slower than that. Different parts of a plate move at different speeds. The plates move in different directions, colliding, moving away from, and sliding past one another. Most plates are made of both oceanic and continental crust.
How many tectonic plates are there in total?
Such boundaries are highly susceptible to earthquakes and volcanic eruptions. Orogeny also takes place at such boundaries. Tectonic plates are defined as major and minor plates depending on their size. There are a total of seven major tectonic plates which cover nearly 95% of the Earth’s surface.
What evidence supports the theory of plate tectonics?
There is variety of evidence that supports the claims that plate tectonics accounts for (1) the distribution of fossils on different continents , (2) the occurrence of earthquakes, and (3) continental and ocean floor features including mountains, volcanoes, faults, and trenches.
Who gave plate tectonic theory?
German meteorologist Alfred Wegener is often credited as the first to develop a theory of plate tectonics, in the form of continental drift.
What is the focus of origin of an earthquake?
The focus is the place inside Earth’s crust where an earthquake originates . The point on the Earth’s surface directly above the focus is the epicenter. When energy is released at the focus, seismic waves travel outward from that point in all directions.
What plates are involved in earthquake?
An earthquake is a sudden motion or trembling in the crust caused by the abrupt release of accumulated stress along a fault, a break in the Earth’s crust. Earthquakes in New Zealand occur because we are located on the boundary of two of the world’s major tectonic plates – the Pacific Plate and the Australian Plate .
What are the basic assumption of the plate tectonic theory?
Plate tectonic theory is based on several assumptions about tectonic processes: 1) that new material is generated by sea-floor spreading at the mid-ocean ridges, which once formed become part of a plate, 2) that surface area is conserved, therefore plate material must be destroyed through another process , and 3) motion ...
