Plate Tectonics, Fault Causing Earthquake Explained by Earth Scientists in Groundbreaking Study

Researchers have reportedly made progress in pinpointing the critical conditions that can lead to catastrophic earthquakes. A recent study published in the peer-reviewed journal Science suggests that the difference between regions that are prone to mild earthquakes and those that may experience devastating tremors could be attributed to the principle of friction. Friction refers to the resistance force that occurs when two materials slide against each other. According to the study, a particular frictional phenomenon that governs the speed at which faults recover after an earthquake could be crucial in determining the risk of a more severe earthquake occurring in the future.

Faults that undergo rapid healing following an earthquake may lead to the formation of stiffer foundations that are at a higher risk of sudden rupture in the future, whereas faults that heal gradually may allow for smooth and continuous movement along the fault without causing any significant damage. These findings could potentially assist scientists in identifying areas that pose a greater risk of seismic activity.

According to Demian Saffer, co-lead author of the study and director of the University of Texas Institute for Geophysics at the Jackson School of Geosciences, the same principles of physics and logic should be relevant for all types of faults across the globe. By utilizing appropriate samples and conducting field observations, it is now possible to make verifiable forecasts about the frequency and magnitude of major seismic slip events that may occur on other major faults, such as the Cascadia in the Pacific Northwest.

Plate Tectonics and Fault

The fact that the earth's crust is not one solid, unmoving piece is the reason why earthquakes occur at all. Instead, it is made up of many tectonic plates that move slowly while the earth's molten core moves. Throughout the planet's existence, continents have moved in this way. Splits in the earth's crust and the rock layers above it are called geological faults. There are faults where one tectonic plate meets another, as well as faults that do not exactly line up with the boundaries of the plates. The earth's layers of rock move slowly concerning each other, creating the right frictional conditions for an earthquake on occasion.

During an earthquake, sudden movement along the fault disrupts the regular movement that humans can't see in their daily lives. Additionally, this movement generates shockwaves that can be felt by all individuals within the earthquake's immediate vicinity. The worst earthquakes have the potential to upend buildings, demolish entire cities, and take the lives of thousands in a single moment. Earthquakes can be extremely large and powerful.

According to recent counts, the magnitude 7.8 earthquake that struck Turkiye and Syria at the beginning of February has so far killed nearly 45,000 people. As another 6.4-magnitude earthquake struck the region on Monday, there were reports of even more buildings falling in the Hatay province of Turkiye. The destructive potential of earthquakes emphasizes the significance of attempting to decipher the mechanisms that cause large quakes. In pursuit of this objective, a test based on rocks from a well-known fault off the New Zealand coast was developed for this new study.

(Photo : (AP Photo/Bernat Armangue))
View of a building destroyed during the earthquakes in Antakya, southeastern Turkiye, Wednesday, Feb. 15, 2023.

ALSO READ: Largest Earthquake in History Caused Enormous Tsunami and Moved Massive Boulders from Chile to New Zealand

Earthquakes in 'Slow Motion'

This particular fault is made up of clay-rich rocks and occasionally experiences "slow motion" earthquakes. The rocks, which had been taken from about a half-mile below the seafloor, were squeezed in a hydraulic press to see how quickly they recovered from the pressure and whether or not they slipped more easily or had more friction. They discovered that the rocks moved easily against each other and healed slowly. This data predicted, when put into a computer model, that rocks of this kind would be associated with a small, slow-motion earthquake about every two years. This prediction is almost the same as the data from this fault in New Zealand.

This suggests, according to researchers, that these clay-rich rocks, which can be found at many earthquake sites around the world, actually slow down and calm earthquakes by making it easier for plates to slowly move in opposite directions. The resulting earthquakes are smaller and more frequent as a result of allowing for more movement within the plates rather than the rocks healing back together quickly and resisting movement for a longer time, as per CTV News.

According to researchers, the same frictional phenomenon explains why moving a stationary box initially requires more effort than keeping it moving. So, does this imply that mankind possesses the key to predicting the time and location of the subsequent major earthquake? Not yet, according to the researchers, there is still a great deal of work to be done before it is that simple to predict earthquakes. However, this study may reveal which faults can cause significant tremors.

Unpredictable Tremors

Srisharan Shreedharan, an assistant professor at Utah State University and study co-lead, stated in the release that although this does not bring them any closer to predicting earthquakes, it does tell them whether a fault is likely to slip silently with no earthquakes or have large ground-shaking earthquakes. Scientists already know that not all large faults have experienced the smaller tremors this study believes are indicators of safer, slower-healing rock structures.

For instance, there is no such history associated with the Cascadia fault, a tectonic plate boundary that runs from Vancouver Island down to northern California in the United States. The Pacific Northwest Seismic Network plans to install sensors in important parts of this fault to see if it conceals the possibility of a devastating earthquake in the future. The findings of the new study, according to Director Harold Tobin, who was not a part of it, give them a good reason to continue.

Tobin stated in the release that they want to focus on the processes in the shallow part of the fault because they control the size of the tsunami. Although fault healing does not provide an exhaustive explanation, it does provide the team with a previously unavailable window into the operation of subduction zone faults.