What decides whether a fault slips slowly or in earthquakes? · revision history

Revision 2

Accepted · core change · record

Changes against revision 1:

Title
What decides whether a fault slips slowly or in earthquakes?
Plain
Some faults release stress in slow slip events lasting days to months, with faint tremor instead of shaking. What property of a fault makes its slip slow instead of fast is not established.
Precise · changed · core
Revision 1: Slow slip events and tectonic tremor at subduction zones move at slip rates of order $1e-6 \text{ to } 1e-5\,\mathrm{cm/s}$, roughly $10 \text{ to } 100$ times the plate rate and about $1e7 \text{ to } 1e8$ times slower than earthquake slip (near $1e2\,\mathrm{cm/s}$). Identify the physical control: near-neutral rate-and-state frictional stability ($a - b \text{ near } 0$) with high pore-fluid pressure, dilatancy strengthening, mixed frictional-viscous rheology, or fault-zone heterogeneity, and whether and when slow slip triggers large earthquakes. An answer is a constitutive model, tested against laboratory data, that reproduces the observed moment-duration scaling, recurrence and tremor of slow slip (review: Burgmann, EPSL 2018, https://doi.org/10.1016/j.epsl.2018.04.062).
Revision 2: Slow slip events and tectonic tremor at subduction zones move at slip rates of order $10^{-6} \text{ to } 10^{-5}\,\mathrm{cm/s}$, roughly $10 \text{ to } 100$ times the plate rate and about $10^{7} \text{ to } 10^{8}$ times slower than earthquake slip (near $10^{2}\,\mathrm{cm/s}$). Identify the physical control: near-neutral rate-and-state frictional stability ($a - b \text{ near } 0$) with high pore-fluid pressure, dilatancy strengthening, mixed frictional-viscous rheology, or fault-zone heterogeneity, and whether and when slow slip triggers large earthquakes. An answer is a constitutive model, tested against laboratory data, that reproduces the observed moment-duration scaling, recurrence and tremor of slow slip (review: Burgmann, EPSL 2018, https://doi.org/10.1016/j.epsl.2018.04.062).
Settled by
Laboratory friction experiments on natural fault-zone materials under in situ fluid pressure that reproduce slow slip, matched to geodetic and tremor catalogs.
Kind
phenomenon
Answer type
mechanism
References
(empty)
Literature status
open
Status note
(empty)
Posed since
(empty)

Decisions