Predictable seismic cycles result from structural rupture barriers on oceanic transform faults
Summary
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 M6 earthquakes over the past three decades. Ocean bottom seismometer data indicate t
Content
# Predictable seismic cycles result from structural rupture barriers on oceanic transform faults
*Published: 2026 May 14*
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 M6 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.
DOI: 10.1126/science.ady6190