Dynamic triggering: Stress modeling and a case study

Gonzalez-Huizar, Hector; Velasco, A. A.

doi:10.1029/2009jb007000

Cited by 46 publications

(51 citation statements)

References 32 publications

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“…The main shock dynamic stress changes are also shown to influence both the local focal mechanism distribution and the spatial distribution of aftershocks, although more weakly than the static stress change. Gonzalez‐Huizar and Velasco [] obtained a comparable result for long‐range dynamic triggering, demonstrating that triggering occurs when the dynamic Coulomb stress change is maximized. The present study considers only the shear stress direction, and so unambiguously shows that the correlation is with shear stress loading in the slip direction, rather than with normal stress change.…”

Section: Discussionmentioning

confidence: 88%

“…The static Coulomb stress change‐triggering model is well established in the literature [e.g., Freed , , and references therein]. Dynamic Coulomb stress has also been related to the spatial distribution of aftershocks [e.g., Kilb et al ., ], and to long‐range triggering [e.g., Gonzalez‐Huizar and Velasco , ], although other work posits that dynamic stress triggering operates primarily through fault weakening [e.g., Brodsky et al ., ; Parsons , ; Johnson and Jia , ; Felzer , ]. The ΔCS is often computed using the simplifying assumption that triggered events occur on the optimally oriented planes (OOPs), those planes with the largest Coulomb stress in the total stress field: σ total = σ back + Δ σ , where σ back is the background stress tensor existing prior to the main shock, and Δ σ is the stress change tensor due to the main shock.…”

Section: Introductionmentioning

confidence: 99%

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The impact of static stress change, dynamic stress change, and the background stress on aftershock focal mechanisms

Hardebeck

2014

JGR Solid Earth

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The focal mechanisms of earthquakes in Southern California before and after four M ≥ 6.7 main shocks provide insight into how fault systems respond to stress and changes in stress. The main shock static stress changes have two observed impacts on the seismicity: changing the focal mechanisms in a given location to favor those aligned with the static stress change and changing the spatial distribution of seismicity to favor locations where the static stress change aligns with the background stress. The aftershock focal mechanisms are significantly aligned with the static stress changes for absolute stress changes of ≥ 0.02 MPa, for up to~20 years following the main shock. The dynamic stress changes have similar, although smaller, effects on the local focal mechanisms and the spatial seismicity distribution. Dynamic stress effects are best observed at long periods (30-60 s) and for metrics based on repeated stress cycling in the same direction. This implies that dynamic triggering operates, at least in part, through cyclic shear stress loading in the direction of fault slip. The background stress also strongly controls both the preshock and aftershock mechanisms. While most aftershock mechanisms are well oriented in the background stress field, 10% of aftershocks are identified as poorly oriented outliers, which may indicate limited heterogeneity in the postmain shock stress field. The fault plane orientations of the outliers are well oriented in the background stress, while their slip directions are not, implying that the background stress restricts the distribution of available fault planes.

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Section: Discussionmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

The impact of static stress change, dynamic stress change, and the background stress on aftershock focal mechanisms

Hardebeck

2014

JGR Solid Earth

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“…The immediate triggering we observe supports this argument with fault patches failing during the second period of transient loading. The transient stresses associated with the passage of surface waves from the IOE are variable in each fault zone (Table ) and are dependent on the source faulting mechanism with respect to the receiver fault orientation and distance from the source [ Gomberg and Bodin , ; Gonzalez‐Huizar and Velasco , ; Hill , ]. At these remote distances, the transient Coulomb stress changes we estimate from the modeled IOE surface wave displacements are on the order of ±1–10 kPa (Table ), with the greatest in the TFZ.…”

Section: Discussionmentioning

confidence: 99%

Delayed dynamic triggering: Local seismicity leading up to three remote M ≥ 6 aftershocks of the 11 April 2012 M8.6 Indian Ocean earthquake

Johnson

Bürgmann

2016

JGR Solid Earth

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The 11 April 2012 M8.6 strike‐slip Indian Ocean earthquake (IOE) was followed by an increase in global seismic activity, with three remote M ≥ 6.0 earthquakes within 24 h. We investigate delayed dynamic triggering by systematically examining three offshore regions hosting these events for changes in microseismic activity preceding the IOE, and during the hours between the IOE surface‐wave arrival and the triggered‐event candidate. The Blanco Fault Zone, USA, and the Tiburón Fault Zone, Mexico, each host a strike‐slip event, and the Michoacán Subduction Zone, Mexico, hosts a reverse event. At these locations we estimate transient Coulomb stresses of ±1–10 kPa during the IOE. Each study area contains a regional seismic network allowing us to examine continuous waveforms at one or more nearby stations. We implement a short‐/long‐term‐average algorithm and template matching to detect events and assess the seismicity with the β‐statistic. Our results indicate low‐magnitude seismicity in the days prior to the IOE and the occurrence of earthquakes during the surface‐wave passage after more than 2 h of transient loading. We find both transtensional tectonic environments respond to the transient stresses with a substantial increase observed in the seismicity rates during the hours after the passage of surface waves. In contrast, seismicity rates remain constant in the subduction zone we investigate during the 14 h delay between the IOE and the large‐magnitude earthquake. The seismicity rate increases we observe occur after many hours of dynamic stresses and suggest the long duration of transient loading initiated failure processes leading up to these M ≥ 6.0 events.

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“…δCFF depends on the fault plane depth d , on its orientation ( α , θ ), on the waves characteristics (amplitude, frequency, and velocity), and on the elastic properties of the medium. More details about the protocol, which is built upon the results of Hill (), can be found in Gonzalez‐Huizar and Velasco (). For stress modeling, we use the seismic data recorded by broadband station YULB operated by Institute of Earth Sciences (Broadband Array in Taiwan for Seismology) and located about 10 km SW of SSNB (Figure ).…”

Section: Stress Perturbations From the 02 June 2013 Mw 62 Nantou Earmentioning

confidence: 99%

Testing the Influence of Static and Dynamic Stress Perturbations On the Occurrence of a Shallow, Slow Slip Event in Eastern Taiwan

et al. 2019

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We report the first evidence for the detection of a slow slip event in the Longitudinal Valley, in eastern Taiwan. The slow event, which lasted about 3.5 days, has been detected by borehole strainmeters. It occurred at shallow depths (about 2 to 4 km), either on the Longitudinal Valley Fault or on the Central Range Fault. Here we investigate whether the event occurrence was influenced by transient and periodic stress perturbations, in particular by the June 2013 Mw 6.2 Nantou earthquake, which occurred about 60 km away and 6 days prior to the event. Modeled changes in Coulomb stress in the direction parallel to the geologic slip vector on the fault planes show negative static stress changes (approximately −1.5 to −1 kPa), while maximum dynamic stress changes generated by the surface waves are ranging from 5.5 to 14.5 kPa. We also observe that the slow event initiated during a maximum of Earth and ocean tidal Coulomb stress changes (about 0.8 to 1.5 kPa). Dynamic and static stress perturbations represent a few percents to tens of percents of the stress buildup through the slow rupture cycle. However, the absence of recurrent events during the 12 years of strain monitoring (2006 to 2018) prevents to estimate the recurrence interval of the slow event, which limits our ability to further interpret the link between the rupture and the perturbations. Finally, there is no large and unique load transient at the time of the initiation, therefore this single event may have likely occurred spontaneously.

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Dynamic triggering: Stress modeling and a case study

Cited by 46 publications

References 32 publications

The impact of static stress change, dynamic stress change, and the background stress on aftershock focal mechanisms

The impact of static stress change, dynamic stress change, and the background stress on aftershock focal mechanisms

Delayed dynamic triggering: Local seismicity leading up to three remote M ≥ 6 aftershocks of the 11 April 2012 M8.6 Indian Ocean earthquake

Testing the Influence of Static and Dynamic Stress Perturbations On the Occurrence of a Shallow, Slow Slip Event in Eastern Taiwan

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