Engineers Conduct Experiment on How Fault Boundaries Can Lead to Major Earthquakes

Caltech engineers have provided substantial experimental evidence of a kind of seismic dispersion currently believed to be responsible for the magnitude 9.0 earthquake that destroyed the Japanese coast in 2011.

Limits of faults leading to major earthquakes

(Photo: CHRISTIAN MIRANDA/AFP via Getty Images)


Fine-grained gravel occurs along fault lines as they rub against each other.

Caltech researchers have illustrated in a new report published in the journal Nature on June 1 that tiny gravels, known as rock gouges, initially stop the spread of earthquakes but later trigger seismic revival, resulting in severe breakups.

According to Vito Rubino, researcher and lead author of the study, the innovative experimental technique allowed them to look closely at the seismic process and identify the critical elements of fracture propagation and friction growth in the gouge. rocky, according to ScienceDaily.

Due to the activation of co-seismic processes of frictional attenuation, fault sections once thought to function as barriers against dynamic failure may in fact host earthquakes, according to their findings.

Rubino and his co-authors Nadia Lapusta, Lawrence A. Hanson, Jr., Professor of Mechanical Engineering and Geophysics, and Ares Rosakis, Theodore von Kármán Professor of Aeronautics and Mechanical Engineering, demonstrated in the article that what Called “stable” or “creeping” faults are not immune to major ruptures after all, as previously thought.

Such faults form when tectonic plates slowly slide past each other without causing large earthquakes, like the San Andreas Fault in central California, which is now creeping.

To create an earthquake simulation, the team first cut a meter-sized piece of translucent homalite in half.

Dynamic fracture nucleation can occur in samples as small as tens of centimeters in diameter, whereas rock samples would require tens of meters.

The scientists then applied massive pressure and shear to both sides of the Homalite, simulating tectonic pressure along a fault line.

Fine-grained quartz powder was used as a substitute for the fault gouge between the pieces.

The scientists then connected the two sections with a short-wire fuse, which served as the “epicenter” of the earthquake.

Read also : Experts study ‘largest earthquake in human history’

Plate boundaries

The majority of earthquakes are caused by movement in small areas along plate boundaries, according to California Academy.

The majority of seismic activity occurs along plate boundaries that are divergent, convergent, or transformed.

When the plates cross, they can get stuck and generate considerable pressure.

The energy is released in the form of seismic waves when the plates eventually give way and slide, due to excessive pressure, causing the earth to shake.

When two tectonic plates move away from each other, it is called spreading.

New crust forms when molten mantle rock bursts along the hole.

These expanding centers, or earthquakes, are usually mild. The Great Rift Valley in Africa, the Red Sea and the Gulf of Aden were formed by the movement of the divergence plates.

When the plates move towards each other and collide, it is called convergence.

Whenever a continental plate collides with an oceanic lithosphere, the thinner, denser, more flexible oceanic plate sinks beneath the thicker, stiffer continental plate.

Subduction is the term for it.

Subduction creates deep ocean trenches, like the one off the coast of South America, where rocks from the continent are torn away.

Related article: Earthquakes swarm in Florence, Italy, as people report tremors since early May

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