[DSRP Evidence](https://dsrpevidence.org/)

# Predictable seismic cycles result from structural rupture barriers on oceanic transform faults

## Details

**Authors** Jianhua Gong, Wenyuan Fan, Jeffrey J. McGuire, Mark D. Behn, Jessica M. Warren, Emily Roland, Margaret S. Boettcher, John A. Collins, Yajing Liu, Christopher R. German

**Year** 2026

**Publisher** Science

**Kind of work** article

**Discipline** Geology

**Secondary disciplines** Oceanography

**Applied** false

[Read it at the publisher](https://doi.org/10.1126/science.ady6190) 
10.1126/science.ady6190

## In authors' words

### Abstract

Earthquakes of magnitude (M) >5.5 on oceanic transform faults (OTFs) repeatedly rupture the same locked patches, sometimes quasiperiodically. These patches are separated by "barriers" that halt earthquake propagation and slip mostly aseismically. However, the physical processes governing this systematic behavior remain unclear. We analyzed two barriers along the Gofar transform fault that have arrested ~15 M 6 earthquakes over the past three decades. Ocean bottom seismometer data indicate that the barriers hosted intense microseismicity before the mainshocks and comprise multistrand faults and transtensional stepovers with 100- to 400-m lateral offset. These characteristics contradict earthquake rupture termination models invoking velocity-strengthening friction or large geometric steps and instead point to damage-enhanced porosity and dilatancy-strengthening mechanisms. By isolating rupture segments, the barriers regulate the quasiperiodic recurrence of OTF earthquakes.

### What they set out to do (purpose)

To determine the physical mechanism by which structural barriers on oceanic transform faults arrest earthquake rupture and produce quasiperiodic recurrence of similar-sized events.

### Who or what was studied (sample)

Two persistent rupture barriers along the Gofar transform fault, East Pacific Rise, which have arrested approximately 15 magnitude-6 earthquakes over three decades, studied using ocean bottom seismometer deployments.

### How they did it (methods)

Analysis of ocean-bottom seismometer records of microseismicity and fault structure around the barriers before and during mainshocks, compared against competing rupture-termination models (velocity-strengthening friction, geometric stepovers, dilatancy strengthening).

### What they found (results)

Ocean-bottom seismometer data showed the barriers hosted intense microseismicity and comprised multistrand, offset fault structures before mainshocks, indicating that damage-enhanced porosity and dilatancy strengthening—rather than velocity-strengthening friction or large geometric steps—regulate the quasiperiodic recurrence of Gofar transform-fault earthquakes by isolating rupture segments.

## Commentary

### In short

The findings identify structural barriers as parts of a fault system that causally regulate whether ruptures stay confined to, or propagate beyond, a given segment, with the barriers acting as boundaries separating distinct locked patches.

**Patterns it shows** D, S, R

**Added** 2026-09-19

**How to cite this** Jianhua Gong, Wenyuan Fan, Jeffrey J. McGuire, Mark D. Behn, Jessica M. Warren, Emily Roland, Margaret S. Boettcher, John A. Collins, Yajing Liu, Christopher R. German (2026). Predictable seismic cycles result from structural rupture barriers on oceanic transform faults. Science.