Dynamic models of earthquakes on the North Anatolian fault zone under the Sea of Marmara: Effect of hypocenter location

Oglesby, D. D.; Martin, Paul Marius; Atakan, Kuvvet; Pucci, Stefano

doi:10.1029/2008gl035037

Cited by 48 publications

(53 citation statements)

References 30 publications

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“…Once the rupture reaches supershear speed, it can remain supershear even outside the area of favorable stress. Other numerical studies have indicated supershear transition mechanisms along strike‐slip faults, including zones of high frictional resistance [ Dunham et al ., ] and zones of favorable prestress [ Fukuyama and Olsen , ; Liu and Lapusta , ] and changes in fault strike [ Oglesby et al ., ; Oglesby and Mai , ]. Laboratory experiments on homalite with a frictional interface [ Xia et al ., ] show the sub‐Rayleigh to supershear transition.…”

Section: Discussionmentioning

confidence: 99%

Dynamically modeling fault step overs using various friction laws

Ryan

Oglesby

2014

JGR Solid Earth

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It is well known that fault step overs can under some circumstances allow through-going rupture and under other circumstances cause rupture to terminate. However, the effects of different friction law formulations on jumping rupture have not been extensively explored. In this study we use the 2-D dynamic finite element method to investigate how different frictional parameterizations affect the ability of rupture to jump a step over, in both extensional and compressional settings. We compare linear slip-weakening friction and three forms of rate-and state-dependent friction: the aging law, slip law, and slip law with strong rate weakening. We have found that for friction parameterizations with the same effective slip-weakening distance, the functional forms of such friction laws can have a significant effect on maximum jump distance. With friction laws scaled to have equivalent fracture energies, we find that the functional forms of such friction laws have a second-order effect on jumping rupture. Finally, with our specific parameterizations we find that delays in rupture across the step over systems can lead to a previously unseen mode of supershear transition once the rupture renucleates on the secondary fault segment, even if the initial stress field precludes such a transition. Studies using multiple friction laws in complex geometries such as fault step overs can lead to better understanding of the dependence of rupture properties on the type of friction law utilized in models and statistical analysis.

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Section: Discussionmentioning

confidence: 99%

Dynamically modeling fault step overs using various friction laws

Ryan

Oglesby

2014

JGR Solid Earth

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“…In natural fault settings the S parameter may vary with the ratio of differential stress to the confining pressure, the values of the static and dynamic friction coefficients, and changing strike of fault segments in an approximately uniform regional stress field (e.g. Lockner & Beeler 2002; Oglesby et al 2008; Shi et al 2008). As in Paper I, we consider the range of values S > 1.77 known to generate ruptures with subshear speed, which is typical for most earthquakes.…”

Section: Detailed Parameter‐space Studymentioning

confidence: 99%

Properties of inelastic yielding zones generated by in-plane dynamic ruptures—II. Detailed parameter-space study

Ben‐Zion

Ampuero

2012

Geophysical Journal International

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SUMMARY We perform a detailed parameter‐space study on properties of yielding zones generated by 2‐D in‐plane dynamic ruptures on a planar fault with different friction laws and parameters, different initial stress conditions, different rock cohesion values, and different contrasts of elasticity and mass density across the fault. The focus is on cases corresponding to large strike‐slip faults having high angle () to the maximum compressive background stress. The simulations and analytical scaling results show that for crack‐like ruptures (1) the maximum yielding zone thickness Tmax linearly increases with rupture distance L and the ratio Tmax/L is inversely proportional to (1 +S)2 with S being the relative strength parameter; (2) the potency density decays logarithmically with fault normal distance at a rate depending on the stress state and S; (3) increasing rock cohesion reduces Tmax/L, resulting in faster rupture speed and higher inclination angle of expected microfractures on the extensional side of the fault. For slip pulses in quasi‐steady state, T is approximately constant along strike with local values correlating with the maximum slip velocity (or final slip) at a location. For a bimaterial interface with , the energy dissipation to yielding contributes to developing macroscopically asymmetric rupture (at the scale of rupture length) with the same preferred propagation direction predicted for purely elastic cases with Coulomb friction. When , representative for thrust faulting, the energy dissipation to yielding leads to opposite preferred rupture propagation. In all cases, is higher on average on the compliant side. For both crack and pulse ruptures with , T decreases and increases for conditions representing greater depth. Significant damage asymmetry of the type observed across several large strike‐slip faults likely implies persistent macroscopic rupture asymmetry (unilateral cracks, unilateral pulses or asymmetric bilateral pulses). The results on various features of yielding zones expected from this and other studies are summarized in a table along with observations from the field and laboratory experiments.

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“…Oglesby et al . [] first noticed the supershear transition on a complex fault system with strike variations. Using an array of broadband stations deployed in Nepal, Vallée et al .…”

Section: Introductionmentioning

confidence: 99%

Supershear transition mechanism induced by step over geometry

Zhang

et al. 2016

JGR Solid Earth

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Few studies have focused on the supershear transition mechanism induced by fault step overs, although seismic observations suggest that rupture speed transitions occur at geometrical complexities on faults. Based on dynamic rupture simulations on fault systems with step overs in a 3‐D full space where the initial stresses preclude a supershear transition on a single buried fault according to the Burridge‐Andrews mechanism, we show that rupture speeds can transit from subshear on the primary fault to supershear on the secondary fault. The low normal stress zone and the high shear stress zone beyond the fault step, which radiate from the end of the primary fault if its rupture arrest is sudden, determine the supershear rupture occurrence on the secondary fault. However, a low shear stress zone traveling at the shear wave speed is also radiated, making the rupture speed return to subshear in most cases. Sustained supershear ruptures are also possible on compressional step overs under certain conditions. Self‐arresting ruptures are observed in the overlap area on the secondary fault. In a half‐space model where supershear rupture is induced by the free surface on the primary fault, the rupture speed on the secondary fault rapidly transits to subshear near the fault step if its width exceeds a critical value.

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Dynamic models of earthquakes on the North Anatolian fault zone under the Sea of Marmara: Effect of hypocenter location

Cited by 48 publications

References 30 publications

Dynamically modeling fault step overs using various friction laws

Dynamically modeling fault step overs using various friction laws

Properties of inelastic yielding zones generated by in-plane dynamic ruptures—II. Detailed parameter-space study

Supershear transition mechanism induced by step over geometry

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