Slow Earthquakes, Preseismic Velocity Changes, and the Origin of Slow Frictional Stick-Slip

Kaproth, B. M.; Marone, Chris

doi:10.1126/science.1239577

Cited by 151 publications

(171 citation statements)

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“…Similar features were observed in a study that imaged the fine-scale seismic structures in the Tokai district, Japan (e.g., Kato et al 2010b). These observations suggest that serpentinite layers in the mantle wedge corner may be important for generating LFEs in subduction zones (Kaproth and Marone 2013), along with high fluid pressures within the oceanic crust.…”

Section: Dehydration Processes Within Subducting Oceanic Crustmentioning

confidence: 92%

Non-volcanic seismic swarm and fluid transportation driven by subduction of the Philippine Sea slab beneath the Kii Peninsula, Japan

et al. 2014

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To understand the mechanism of an intensive non-volcanic seismic swarm in the Kii Peninsula, Japan, we used a dense seismic linear array to measure fine-scale variations of seismic velocities and converted teleseismic waves. A low-velocity anomaly confined to just beneath the seismic swarm area is clearly imaged, which correlates spatially with an uplifted surface area and a highly conductive and strong attenuative body. These results suggest that fluids such as partial melt or water are present beneath this non-volcanic seismic swarm area. It is notable that the island arc Moho below the seismic swarm area is at a depth of approximately 32 km in the northern part of the seismic swarm area and shallows to approximately 20 km towards the south, due to the raised structure of the serpentinized mantle wedge. In addition, we show that the hydrated oceanic crust of the subducting Philippine Sea slab is characterized by low velocities with a high Poisson's ratio at depths of less than 40 km. In contrast, dehydration conversion from oceanic basalt to eclogite takes place at depths greater than 50 km. Water released from the subducting oceanic crust could cause serpentinization of the mantle wedge and infiltration into the forearc base of the overlying plate. The interaction between dehydration of the subducting oceanic crust and hydration of the mantle wedge and overlying plate exerts an important role in driving the non-volcanic seismic swarm activity in the Kii Peninsula.

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Section: Dehydration Processes Within Subducting Oceanic Crustmentioning

confidence: 92%

Non-volcanic seismic swarm and fluid transportation driven by subduction of the Philippine Sea slab beneath the Kii Peninsula, Japan

et al. 2014

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“…If K < K c , then perturbations from steady-state are unstable and the system's oscillations grow without bound in phase space. One can observe a continuum of behaviors between slow-slip events 21 and large elastodynamic ruptures indexed by the stiffness ratio K/K c , as also observed in laboratory experiments [58][59][60] . A larger ratio implies more stable and slower slip events, whereas a smaller ratio implies instability and fast slip.…”

Section: Stability Of Semi-brittle Fault Zonesmentioning

confidence: 75%

“…In particular, we observe small stress drops in the range 10-200 kPa, short recurrence times of a few months to a few years, and sometimes more regular periodicity than for earthquakes 14 . Some characteristics of slow-slip events can be explained within the context of rate-and-state friction 15,16 with conditionally stable behavior [17][18][19][20][21] . Runaway frictional instabilities require a critical size for nucleation that depends on the frictional parameters and the effective confining pressure.…”

mentioning

confidence: 99%

Slow-slip events in semi-brittle serpentinite fault zones

Goswami¹,

Barbot²

2018

Preprint

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Slow-slip events are earthquake-like events only with much lower slip rates. While peak coseismic velocities can reach tens of meters per second, slow-slip is on the order of 10 −7±2 m/s and may last for days to weeks. Under the rate-and-state model of fault friction, slow-slip is produced only when the asperity size is commensurate with the critical nucleation size, a function of frictional properties. However, it is unlikely that all subduction zones embody the same frictional properties. In addition to friction, plastic flow of antigorite-rich serpentinite may significantly influence the dynamics of fault slip near the mantle wedge corner. Here, we show that the range of frictional parameters that generate slow slip is widened in the presence of a serpentinized layer along the subduction plate interface. We observe increased stability and damping of fast ruptures in a semi-brittle fault zone governed by both brittle and viscoelastic constitutive response. The rate of viscous serpentinite flow, governed by dislocation creep, is enhanced by high ambient temperatures. When effective viscosity is taken to be dynamic, long-term slow slip events spontaneously emerge. Integration of rheology, thermal effects, and other microphysical processes with rate-and-state friction may yield further insight into the phenomenology of slow slip.The dynamics of fault slip at subduction zones can assume a wide range of behaviors. A continuum of slip modes that includes fast earthquakes, slow-slip events, and stable creep determines seismic hazards 1,2 . Along the megathrust, earthquakes, very low frequency earthquakes, and tsunami earthquakes are typically found updip of the continental Mohorovicic (Moho) discontinuity. In contrast, slow-slip events are often found close to or below the continental Moho depth at many subduction zones around the circum-Pacific seismic belt 3 , even though some happen at shallow depth, notably in New Zealand 4-6 and Costa Rica 7,8 . Slow-slip events at subduction zones worldwide often embody similar, characteristic features [9][10][11][12][13] . In particular, we observe small stress drops in the range 10-200 kPa, short recurrence times of a few months to a few years, and sometimes more regular periodicity than for earthquakes 14 . Some characteristics of slow-slip events can be explained within the context of rate-and-state friction 15,16 with conditionally stable behavior [17][18][19][20][21] . Runaway frictional instabilities require a critical size for nucleation that depends on the frictional parameters and the effective confining pressure. For sufficiently small velocity-weakening asperities, only creep spontaneously occurs. Slow-slip events emerge spontaneously when the asperity size is commensurate to critical nucleation size 22 . As slow-slip events are now found close to universally at subduction zones [23][24][25][26][27][28] , it is unrealistic to expect the same combination of parameters across widely distant regions (Fig. 1A). Several authors developed and investigated other friction l...

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“…Furthermore, the measurements of local strain at P c = 60 MPa show that a rupture seems to have nucleated at a location close to the lower edge of the saw-cut (orange gauge) just before the onset of the long approximately 1-s drop in shear stress ( Figure 3F), and that it then propagated upward (toward the purple gauge) at speeds ranging from 0.07 to 0.22 m/s. Slow stick-slip behavior has been reported in recent friction experiments on lizardite-rich gouge conducted at room temperature (Kaproth and Marone 2013).…”

Section: Mechanical Datamentioning

confidence: 97%

Effect of stress state on slow rupture propagation in synthetic fault gouges

Hirauchi

Muto

2015

Earth, Planets and Space

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Slow slip events (SSEs) in subduction zones are known to proceed so sluggishly that the associated slow ruptures do not generate any detectable radiating seismic waves. Moreover, they propagate at speeds at least four orders of magnitude slower than regular earthquakes. However, the underlying physics of slow slip generation has yet to be understood. Here, we carry out laboratory studies of unstable slip along simulated fault zones of lizardite/chrysotile (liz/ctl) and antigorite (i.e., low-and high-temperature serpentine phases, respectively) and olivine, under varying conditions of normal stress, with the aim of better understanding the influence of stress state on the process of slow rupture along the plate interface. During a single unstable slip, we clearly observe a slow rupture phase that is often followed by an unstable, high-speed rupture. We find that lower fault-zone friction coefficients (μ values from 0.7 down to 0.5) lead to increasing degree of the slow rupture mode, and also that the slow rupture velocities (V r = 0.07 to 5.43 m/s) are largely consistent with those of short-term SSEs observed in nature. Our findings suggest that the generation of SSEs is facilitated by conditions of low normal stress and low fault-zone strength along the plate interface, which may be weakened by metamorphic reactions that result in the production of hydrous phases (e.g., serpentine) and/or the direct involvement of fluid itself, leading to a reduction in effective normal stress.

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Slow Earthquakes, Preseismic Velocity Changes, and the Origin of Slow Frictional Stick-Slip

Cited by 151 publications

References 30 publications

Non-volcanic seismic swarm and fluid transportation driven by subduction of the Philippine Sea slab beneath the Kii Peninsula, Japan

Non-volcanic seismic swarm and fluid transportation driven by subduction of the Philippine Sea slab beneath the Kii Peninsula, Japan

Slow-slip events in semi-brittle serpentinite fault zones

Effect of stress state on slow rupture propagation in synthetic fault gouges

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