A New Technology That Smells Earthquakes!

Researchers at Caltech can now detect even the smallest vibrations in the Earth by sending light pulses deep into the ground.

As reported by IE, beneath our feet, deep within the Earth, lies a mysterious boundary that separates the Earth's crust from its mantle. This boundary, known as the Mohorovičić Discontinuity (Moho), has long captivated scientists.

Now, a new method has provided fresh insights into this hidden boundary, leading researchers at Caltech to introduce a new seismic technology called Distributed Acoustic Sensing (DAS).

Using DAS, the Moho is explored by analyzing reflected seismic waves, and researchers can detect even the smallest vibrations deep within the Earth by sending light pulses through a cable.

James Atterholt, a postdoctoral researcher at the United States Geological Survey, says: "The Moho is a truly interesting boundary for seismologists because it tells us what is happening inside and between tectonic plates at depth."

Study of Moho Structure

The Moho is located at a depth of 12 to 43 miles beneath the continents.

Traditional methods of imaging the Moho either have low resolution or are very expensive. Now, this DAS method turns fiber optic cables into seismometers.

When an earthquake occurs, seismic waves radiate outward, some of which are reflected by the Moho.

Laser pulses sent through these cables can provide data about ground vibrations caused by earthquakes or other disturbances, allowing researchers to study the Earth's subsurface.

Interestingly, the method was originally developed for analyzing reflected laser light along the entire length of the fiber optic cable. This allows them to understand the internal movements of the Earth, making the cable act like a network of many small seismometers.

Distributed Acoustic Sensing (DAS) allows researchers to map the Moho's structure with high resolution over large areas, providing precise insights into this critical geological boundary.

Atterholt explained in a press release: "This method can tell us whether major faults penetrate the mantle, how ancient and contemporary processes have left their mark on the continents, and how strong the deep crust is in certain places."

New Insights from Moho

The team used the DAS method to gain new insights into the Moho by studying earthquakes with a fiber optic cable in the Mojave Desert, mapping the Moho over two years.

They discovered that the Garlock Fault extends deeper into the mantle than previously thought in this region. The Garlock Fault is a major player in seismic activity in Southern California.

However, data also shows that the Moho is significantly tilted beneath the Coso volcanic field, a dormant volcanic region north of Mojave.

This research highlighted the connection between the mantle's heat source and the magma chamber in the Coso volcanic field, emphasizing the geothermal potential of the region.

Atterholt says: "Everything happening deep within the lithosphere, the outermost part of the Earth, including the crust and upper mantle, is what you can explore with DAS—only your creativity limits what you can do."

This study was published in Science Advances.