Earthquakes result from the sudden movement along faults found within the earth. These movements release elastic strain energy stored up in the form of a seismic wave.
The waves move through the earth, causing the shaking of the ground surface.
More than a million earthquakes occur every year of different frequencies and magnitudes. They include some too small to be felt.
It is pretty easy to discover the relationship between plate boundaries and earthquakes. Most earthquakes occur near plate boundaries.
Numerous transform faults have happened to offset the shallow ocean divergent plate margins. Before we get any deeper, let’s first answer the question,
Do Earthquakes Occur at Divergent Plate Boundaries?
Earthquakes at divergent plate boundaries occur when a new crust forms and another gets pushed apart, causing the crust to crack.
Earthquakes along divergent plate margins are shallow, usually a depth of fewer than 30 km, because of the permanent deformation of rocks.
What Are Divergent Plate Boundaries?
Divergent plate boundaries are places on the earth’s surface where plates move away from each other.
This phenomenon happens above convection currents that are rising. The rising current pushes up the lithosphere, causing it to lift as it flows beneath it.
The lateral flow below it causes the material on the plate to get dragged. These follow the direction of the convection current flow. The plate at the top of the uplift crest gets stretched thin. It causes it to break and pull apart.
Earthquakes are pretty common along divergent boundaries. They frequently happen on the mid-Atlantic ridge and East Pacific rise.
These earthquakes are characteristically restricted. They happen close to the ridge and are consistently at a depth of fewer than 30 km.
Types Of Divergent Plate Boundaries
1. Divergent Plate Boundary – Oceanic
The oceanic divergent plate boundary gets formed when a divergent boundary occurs below an oceanic lithosphere.
A shallow ocean ridge forms when the divergent boundary occurs. The boundary causes a convectional current below the plate to lift the lithosphere.
A deep fissure gets subsequently produced due to the stretching of the lithosphere by extensional forces.
Pressure on the super-heated mantle material underneath reduces after the fissure opens. It melts, and the new magma fills the fissure.
The magma that flows into the fissure solidifies, and the process occurs repeatedly.
Examples of Oceanic Divergent Plate Boundaries
- Mid-Atlantic Ridge
- The East Pacific Ride
- The Juan de Fuca Ridge
- The Galapagos Rise
2. Divergent Plate Boundary – Continental
The divergent continental boundary form when a divergent boundary forms beneath a continental plate.
The pull-apart happens when a divergent boundary forms underneath a thick continental plate. It is not violent enough to create a clean break through the plate material.
Consequently, the convection currents lift causes the thick continental plate to arch upwards. At the same time, extensional forces pull the plate thin and cause it to fracture. They form a rift-shaped feature.
Normal faults are developed on the two sides of the rift as the two continental plates pull away. It happens while the block at the center slides downwards. Earthquakes usually happen due to fracturing and movement.
A long linear lake gets formed by rivers and streams flowing into the sinking rift valley. It happens at the onset of the rift formation.
Ocean waters may be allowed to flow in as the rift might drop below sea level as it grows deeper. It could produce a new ocean basin if the rift continues to grow.
Examples of Continental Divergent Plate Boundaries
- The East Africa Rift.
- The Red Sea Rift
- West Antarctic Rift
3. Earthquakes And Plate Tectonics
Plate tectonics and earthquakes are closely related. Most earthquakes result from a movement happening in narrow zones along plate boundaries.
Most Seismic activity happens at the following boundaries: transformed, convergent and divergent.
Individual plates on the earth’s surface of varying sizes usually move about at different speeds about the earth’s surface.
Plates sometimes get caught as they move past each other due to pressure hence building pressure. An earthquake forms when this stress is released.
There is tectonic activity manifested in earthquakes where plates slide by each other. They pull apart or collide. Most seismic activity on the earth’s surface occurs at the plate boundaries.
The seismic activity within the plate can also happen when there is a build-up in the plate. Earthquakes in the transform plate boundaries are mighty and shallow.
Earthquakes that occur in the convergent plate boundaries. At the place where a pair of continental plates collide.
They are also mighty and deep. The earthquakes that occur at divergent plate boundaries are usually weak and shallow.
Generally, the most powerful and deepest earthquakes occur at plate subdivisions. They occur at collision zones in convergent plate boundaries.
Earthquakes At Divergent Plate Boundaries
Earthquakes are common where plates diverge. As a new crust forms, the old crust gets displaced.
Very shallow and large subduction zone earthquakes occur from the contact of the two plates along the plate boundary.
Earthquakes that occur at divergent plate margins tend to be shallow. They usually have a depth of fewer than 30 km. This phenomenon results from the nature of the type of rock found below those depths.
The rock found below those depths is too weak and got and cannot avoid permanent deformation.
It is due to the stresses in those settings. Since the deformation is permanent, the rocks do not snap back to their original shape even after removing the stress.
The effect of the rocks not snapping back is no shaking. In shallow earthquakes, there is a slow increase in the stresses on the fault.
It is due to the slow movement of the tectonic plates. It happens where sliding begins when the stresses exceed static friction.
The extent of the rapidness of the spreading of the shallow oceanic ridges determines where the earthquakes happen. It is usually along shallow oceanic ridges.
The Pacific-Antarctic Ridge is diverging at about 42 to 94 mm per year, depending on the ridge’s location. This rapid spreading makes the rocks found near the spreading center’s axis weak and hot.
As a result of this, the majority of the earthquakes usually occur along transform faults. It happens when the rocks are more robust and cooler. New ocean crust is bent upward into high and wide ridges along the rapidly diverging ridges.
The bend is relaxed as the spreading continues, and the crust moves away from the ridge. It causes the crust to stretch and break. This phenomenon causes earthquakes that stretch many kilometers away from the ridge.
The Southwest Indian Ridge spreads very slowly. It moves 14mm annually.
Rock strength differs between the ridges.
The slow ridge has more substantial rocks, while the fast ridge has weak rocks.
In the gradually spreading surrounding, earthquakes form when the rocks found along the axis of the ridge stretch and break.
Earthquakes get more fairly distributed between transform and divergent boundary segments than fast-spreading ridges.
Earthquakes generated in continental rift zones tend to be shallow. They get more broadly scattered than those generated along shallow ocean ridges.
Lake Baikal is the world’s deepest, oldest, and a largest freshwater lake. It was formed 25 million years ago due to continental drifting.
The earthquakes in the Lake Baikal region get relatively more widely spread when compared to those along the shallow ocean ridges.
Faulting within the continental crust occurs in a disorganized manner.
In contrast to shallow ocean ridges, continental rift zones do not have well established spreading center.
Another reason for this is that preexisting geological structures within the continental crust. They affect the location of faults in the continental rift zones and thus affect the earthquakes.
The rock found below those depths is too weak and got and cannot avoid permanent deformation.
It is due to the stresses in those settings. Since the deformation is permanent, the rocks do not snap back to their original shape even after removing the stress.
Earthquakes get more fairly distributed between transform and divergent boundary segments than fast-spreading ridges.
Continental rift zones experience mild tremors but are more broadly scattered. They differ from those generated along shallow ocean ridges.
The phenomenon results from the nature of the type of rock found below those depths.
Conclusion
It is pretty easy to discover the relationship between plate boundaries and earthquakes.
It is because most earthquakes occur near plate boundaries. Earthquakes are pretty common along divergent boundaries.
They get recorded on the East Pacific rise and mid-Atlantic ridge.
Divergent plate boundaries are places on the earth’s surface where plates move away from each other. Earthquakes at divergent plate boundaries occur when a new crust forms and another gets pushed apart. It causes the crust to crack.
Earthquakes along divergent plate margins are shallow. They are usually at a depth of fewer than 30 km because of the permanent deformation of rocks.
![Best Cybersecurity Companies & Services [Top Rated 2022]](https://technewsdaily.com/wp-content/uploads/2022/04/Best-Cybersecurity-Companies-Services-Top-Rated-2022_1-75x75.jpg)
