Intraplate earthquakes are a particularly destructive type of seismic activity that can cause significant damage to buildings and infrastructure. They are also difficult to predict compared to other types of earthquake faults. It is important for civil engineers to consider the challenges of intraplate earthquakes to ensure that the structures we build are resilient to this type of seismic activity. In this blog, we look at the characteristics of intraplate earthquakes and the best methods civil engineers can use to mitigate their effects.
What is an earthquake
Earthquakes occur around the world every day. Most are harmless, but some can be very destructive. Earthquakes have been recorded for thousands of years. An earthquake is a sudden, rapid shaking of the ground caused by underground rock movements. These movements are called seismic waves and they propagate in all directions from the source or point of origin below the Earth's surface (the epicenter of the earthquake). Earthquakes occur when stresses in the Earth's crust force rocks to suddenly slide past each other without warning. When these rocks rub together, energy builds up and is suddenly released in the form of seismic waves as one large piece of rock pushes against another. The magnitude of an earthquake is measured on a scale of 1 to 10, with 7 being massive destruction and 10 being total destruction. Magnitude does not indicate the depth of the earthquake or the size of the affected area; it simply measures how much energy was released at the exact location in space and time.
There are essentially two types of earthquakes
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Intraplate earthquakes, which occur at tectonic plate boundaries but not at the plate boundaries themselves, are often the result of stresses caused by the subsidence of oceanic lithosphere into the underlying asthenosphere.
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Tectonic earthquake. This occurs at convergent boundaries between two or more tectonic plates. Plates can collide or one plate can slide past another, releasing energy.
What are intraplate earthquakes
An intraplate earthquake is a type of seismic activity that occurs within a tectonic plate, rather than at its edge, like an interplate earthquake.
Most large earthquakes are intraplate earthquakes. Intraplate earthquakes occur in association with faults that are not plate boundaries and involve the deformation and flow of lithospheric plates in response to forces such as mantle convection currents, back thrust, plate pull, subduction thrust loading, wedge loading of accretion or volcanic activity. Intraplate regions include mid-ocean ridges and deep ocean basins far from continents. They can also be found inland, in regions far from active plate boundaries.
How do intraplate earthquakes occur?
An intraplate earthquake is an earthquake that occurs within a tectonic plate rather than at its edges. Tectonic plates move very slowly (a few centimeters per year), and can accumulate enormous tensions over time, which are suddenly released during an earthquake. Intraplate earthquakes differ from other types in both their formation and their behavior. They occur several hundred kilometers within a tectonic plate and not near plate boundaries. They also do not appear to follow plate boundaries and often move in unusual trajectories, suggesting that they are not caused by movement along faults but by different processes than those occurring at plate boundaries.
Intraplate earthquakes can be caused by the slow deformation of an entire section of a tectonic plate, rather than just its edges, causing stresses to build up at depth until they form a tectonic plate. earthquake . The two Nankai earthquakes that devastated Japan in 1944 were intraplate events caused by such mechanisms: at least part of their epicenters were within 660 km of any boundary between two tectonic plates, since Japan is part of a single large oceanic plateau that is divided into several subplates without clear boundaries between them.
An intraplate earthquake also occurs when forces from the movement of the Earth's crust push one tectonic plate against another. The pressure created by this collision causes a sudden release of this tension, resulting in an earthquake. Intraplate earthquakes are not limited to a single geographic region and occur throughout the world, including on continental plates. They can be triggered by local or regional tectonic changes, as well as other natural mechanisms such as landslides or volcanic activity. Intraplate earthquakes have occurred throughout history, but scientists have only recently begun building models to predict where they will occur next.
Final considerations
Intraplate earthquakes are fundamentally different from earthquakes that occur at the tectonic plate boundary and occur far from the plate boundary. In general, about 5% can be attributed to this category.
Intraplate earthquakes are believed to be caused by the stresses developed by plate movement within the plate, as well as weak zones created by the movement.
