Preparatory Slip in Laboratory Faults: Effects of Roughness and Loading Rate

Guerin-Marthe, S.; Kwiatek, Grzegorz; Wang, Lei; Bonnelye, Audrey; Martínez‐Garzón, Patricia; Dresen, Georg

doi:10.1002/essoar.10511105.1

Cited by 2 publications

(2 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Existing work suggests that fault zone properties evolve during the seismic cycle in response to stress changes and microcracking prior to rupture with subsequent post-seismic healing 1,2 . Such changes are observed commonly in lab experiments [3][4][5][6][7][8][9][10][11][12][13][14][15] and őeld data conőrm these expectations in some cases, showing changes in elastic wave speed prior to earthquake fault slip, volcanic activity and landslides [16][17][18][19][20][21][22] . However, distinguishing subtle changes in seismic behavior or fault properties prior to and after earthquakes, even in locations with dense seismic networks, is challenging [23][24][25][26][27][28][29][30][31] .…”

Section: Introductionmentioning

confidence: 74%

Probing the Evolution of Fault Properties During the Seismic Cycle with Deep Learning

Laurenti,

Paoletti,

Tinti

et al. 2024

Preprint

View full text Add to dashboard Cite

We use seismic waves that pass through the hypocentral region of the 2016 M6.5 Norcia earthquake together with Deep Learning (DL) to distinguish between foreshocks, aftershocks and time-to-failure (TTF). Binary and N-class models defined by TTF correctly identify seismograms in test with >90% accuracy. We use raw seismic records as input to a 7 layer CNN model to perform the classification. The DL models successfully distinguish seismic waves pre/post mainshock in accord with lab and theoretical expectations of progressive changes in crack density prior to abrupt change at failure and gradual postseismic recovery. Performance is lower for band-pass filtered seismograms (below 10 Hz) suggesting that DL models learn from the evolution of subtle changes in elastic wave attenuation. Tests to verify that our results indeed provide a proxy for fault properties included DL models trained with the wrong mainshock time and those using seismic waves far from the Norcia mainshock; both show degraded performance. Our results demonstrate that DL models can track the evolution of fault zone properties during the seismic cycle, which could improve earthquake early warning and seismic hazard analysis.

show abstract

Section: Introductionmentioning

confidence: 74%

Probing the Evolution of Fault Properties During the Seismic Cycle with Deep Learning

Laurenti,

Paoletti,

Tinti

et al. 2024

Preprint

View full text Add to dashboard Cite

show abstract

“…In the triaxial shear configuration used here (Figure 1a), the stiffness of loading system k s may be calculated from the combined contribution of the apparatus and the rock matrix (Guérin‐Marthe et al., 2023; He et al., 1998), as given by

{k}_{\mathrm{s}}=\frac{{\cos }^{2}\hspace*{.5em}\beta \hspace*{.5em}\sin \hspace*{.5em}\beta }{1/{k}_{\mathrm{m}}+1/{k}_{\text{app}}}

where k app is the apparatus axial stiffness and k m represents the axial stiffness of the rock matrix. The apparatus stiffness is ∼83 kN/mm, equivalent to k app ≈ 1,060 MPa/mm for a sample diameter of 10 mm.…”

Section: Discussionmentioning

confidence: 99%

Experimental Insights Into Fault Reactivation and Stability of Carrara Marble Across the Brittle–Ductile Transition

Niu,

Zhou,

Shao

et al. 2024

JGR Solid Earth

View full text Add to dashboard Cite

Little is known about the impact of pressure (P) and temperature (T) on faulting behavior and the transition to fault locking under high P–T conditions. Using a Paterson gas‐medium apparatus, triaxial compression experiments were conducted on Carrara marble (CM) samples containing a saw‐cut interface at ∼40° to the vertical axis at a constant axial strain rate of ∼1 × 10−5 s−1, P = 30–150 MPa and T = 20–600°C. Depending on the P–T conditions, we observed the complete spectrum of deformation behavior, including macroscopic (shear) failure, stable sliding, unstable stick‐slip, and bulk deformation with locked faults. Macroscopic failure and stable sliding were limited to P < 100 MPa and T = 20°C. In contrast, at P ≥ 100 MPa or T ≥ 500°C, faults were locked, and samples with bulk deformation experienced strain hardening at strains ≤8.8%. At T = 100–400°C and P ≤ 100 MPa, we observed unstable stick‐slip behavior, where both fault reactivation stress and subsequent stress drop increased with increasing pressure and temperature, associated with increasing matrix deformation and less fault slip. Microstructures indicate a mixture of microcracking, twinning and dislocation activity (e.g., kinking and undulatory extinction) that depends on P–T conditions and peak stress. The transition from slip to lock‐up with increasing pressure and temperature is induced by an enhanced contribution of crystal plastic deformation. Our results show that fault reactivation and stability in CM are significantly influenced by P–T conditions, probably limiting the nucleation of earthquakes to a depth of a few kilometers in calcite‐dominated faults.

show abstract

Preparatory Slip in Laboratory Faults: Effects of Roughness and Loading Rate

Cited by 2 publications

References 0 publications

Probing the Evolution of Fault Properties During the Seismic Cycle with Deep Learning

Probing the Evolution of Fault Properties During the Seismic Cycle with Deep Learning

Experimental Insights Into Fault Reactivation and Stability of Carrara Marble Across the Brittle–Ductile Transition

Contact Info

Product

Resources

About