Study Finds underwater "Brake Zones" Could Act As Natural Barriers To Halt Earthquakes

A new study has explained how certain hidden zones beneath the ocean can stop earthquakes from spreading further. Researchers say these underwater "brake zones" act like natural barriers that halt seismic activity, reported NYPost.

The findings were published in the journal Science and help explain a long-standing mystery about how some earthquakes stop in specific areas again and again.

Lead author Jianhua Gong, Assistant Professor of Earth and Atmospheric Sciences at Indiana University Bloomington, said that scientists have known about these barriers for a long time but did not understand their nature.

He explained that the question had always been what these barriers are made of and why they consistently stop earthquakes in every cycle.

The research focused on the Gofar fault, a fracture on the seafloor located about 1,000 miles off Ecuador in the Pacific Ocean. This fault has been producing nearly identical earthquakes over the past 30 years.

During this period, magnitude six earthquakes have occurred in the same locations every five to six years, showing a consistent pattern.

Researchers discovered that these brake zones are formed by a combination of seawater and rock. These elements work together to stop earthquakes from spreading further.

To understand this, scientists analysed data from two major ocean-floor experiments conducted in 2008 and between 2019 and 2022. Seismometers placed on the seafloor recorded thousands of small earthquakes before and after two major tremors.

How The Brake Zones Work

The study found that these zones show intense tremor activity before a major earthquake but become quiet immediately after it.

Scientists explained that these zones are not solid rock barriers but complex regions where the fault splits into multiple branches, creating openings. These cracks fill with seawater, and during a large earthquake, the porous rocks lock up and stop the movement, acting like a built-in mechanism to halt the tremor.

Jianhua Gong said that these brake zones are not passive features but active and dynamic parts of the fault system. He added that understanding how they work changes how scientists view the limits of earthquakes on such faults.

Researchers believe that similar brake zones may exist across oceans worldwide. Studying them could help improve predictions about when and where earthquakes may occur.

This research is particularly important as some major fault lines, such as the Hayward Fault in the United States, are considered overdue for a significant earthquake. This fault is capable of producing magnitude 7 earthquakes, which are stronger than the 1989 Loma Prieta earthquake that caused deaths and injuries in California.