Earthquakes That Follow a Clockwork Pattern: New Insights Into Predictable Faults

For more than three decades, scientists have struggled to understand why some underwater fault lines produce earthquakes that seem to arrive at regular intervals and with consistent magnitudes. A recent study of the Gofar transform fault, located between the Pacific and Nazca plates off the coast of Ecuador, offers a scientific explanation.

The fault is surrounded by barrier zones—networks of small fractures that act as natural brakes. When seawater seeps into these zones, a process called dilatancy strengthening builds resistance against the fault’s movement. The fluid‑filled rock temporarily locks up, absorbing the energy from minor tremors and preventing larger, more destructive quakes.

Observations from ocean‑bottom seismometers deployed in 2008 and again from 2019 to 2022 recorded thousands of micro‑earthquakes around the barrier zones. The data showed a striking pattern: the faults released energy in a rhythmic cycle, producing magnitude‑six earthquakes roughly every five to six years.

“The barrier zones are not passive; they actively regulate the fault’s behavior,” said lead researcher Jianhua Gong. “Understanding how these structures work changes how we model earthquake risk on similar faults worldwide.”

While the Gofar fault lies in a low‑risk area for human populations, the mechanism uncovered could apply to other oceanic transform faults and even some onshore systems. If similar barrier‑zone networks exist elsewhere, they might help geologists predict when and where future quakes could occur.

“Our findings give fresh insight into earthquake physics and provide robust constraints for numerical models,” the researchers added. By integrating barrier‑zone dynamics, future hazard assessments could become more accurate, potentially giving communities more time to prepare for seismic events.