Much of the relief of the abyssal hills covering the ocean basins is believ
ed to originate from faulting of oceanic crust at mid-ocean ridges. The tim
escale over which faults grow is controversial, however, with some authors
arguing that faults continue to grow in places for 0.5 m.y. or more based o
n increasing relief of fault scarps with distance from ridge axes. We exami
ne Deep Tow profiler records of the Galapagos Spreading Centre, in which ba
sement reflections allow scarp relief to be measured beneath the sediment c
over, and find that relief does not increase but decreases systematically t
o 40 km off-axis (1.5 Ma seafloor). Since reversal of fault offsets is unli
kely in this tectonic setting, we interpret this result as indicating that
variations in fault statistics could reflect temporal variations in the tec
tonic or volcanic state of the ridge crest, not necessarily progressive fau
lt growth with age as previously assumed. Resolving the issue of fault long
evity will therefore require independent data on the timing of fault growth
and distribution of present growth activity. We suggest some possible alte
rnative indicators of fault longevity and discuss more generally the implic
ations of volcanic flows to studies of faulting at ridges.