Title:<\/p>\n
Anatomy of a predictable seismic cycle at the Gofar oceanic transform fault<\/p>\n
<\/p>\n
Abstract:<\/p>\n
Oceanic transform faults host some of the most regular earthquake
\ncycles observed on Earth. At the Gofar transform fault on the East Pacific
\nRise, characteristic Mw 6 earthquakes repeatedly rupture the same fault
\npatches every 5 to 6 years, and adjacent barrier zones consistently arrest
\nthese ruptures. The short recurrence interval makes Gofar a natural
\nlaboratory for observing the full seismic cycle within a human
\nobservational timescale. In this talk, I will synthesize results from two
\nocean-bottom seismometer experiments in 2008 and 2019\u20132022 to examine the
\ncontrols of fault architecture, damage, healing, and fluids on the seismic
\ncycle. High-resolution seismicity catalogs show that the eastern (G1) and
\nwestern (G3) segments share a structured architecture, in which locked
\nrupture patches are separated by persistent barrier zones that host
\nelevated background seismicity and foreshocks before mainshocks and become
\nquiescent afterward. Within the G3 barrier, episodic seismicity bursts
\nfrequently migrate along diffusion-like fronts, consistent with coupled
\nfluid-pressure transients and aseismic creep regulated by dilatancy in a
\nfluid-saturated, damaged fault zone. Elevated pore-fluid pressure
\nmechanically weakens such barriers relative to the locked rupture patches,
\nas indicated by microearthquake focal mechanisms whose faulting types vary
\nsystematically along strike within a nearly uniform stress field, and this
\ncontrast explains the distinct slip modes of the two fault elements. The
\ncharacteristic Mw 5\u20136 earthquakes consistently produce abrupt seismic
\nvelocity reductions, but the fault zones heal within 1 to 3 months, much
\nfaster than stress reaccumulates over the recurrence interval. Because the
\nbarriers isolate the rupture patches and the fault zones heal rapidly, each
\ncycle begins from a similar fault-zone state. These patterns repeat across
\nsegments and seismic cycles, rendering a predictable earthquake cycle.<\/p>\n","protected":false},"excerpt":{"rendered":"