Investigation of Dynamic and Static Effects on Earthquake Triggering Using Different Rate and State Friction Laws and Marmara Simulation

2020 ◽  
Author(s):  
Eyup Sopaci ◽  
Atilla Arda Özacar
Keyword(s):  
Onset Time ◽  
Static Stress ◽  
Fault System ◽  
Dynamic Effects ◽  
Earthquake Triggering ◽  
Dynamic Changes ◽  
System Parameters ◽  
Fault Segment ◽  
Stress Changes ◽  
Rate And State Friction

<p>The clock of an earthquake can be advanced due to dynamic and static changes when a triggering signal is applied to a stress-loading fault. While static effects decrease rapidly with distance, dynamic effects can reach thousands of kilometers away. Therefore, earthquake triggering is traditionally associated to static stress changes at local distances and to dynamic effects at greater scales. However, static and dynamic effects near the triggering signal are often nested, thus identifying which effect dominates, becomes unclear. So far, earthquake triggering has been tested using different rate-and-state friction (RSF) laws utilizing alternative views of friction without much comparison. In this study, the analogy of an earthquake is simulated using single degree of freedom spring-block systems governed with three different RSF laws, namely “Dieterich”, “Ruina” and “Perrin”. First, the fault systems are evolved until they reach a stable limit cycle and then static, dynamic and their combination are applied as triggering signals. During synthetic simulations, effects of the triggering signal parameters (onset time, size, duration and frequency) and the fault system parameters (fault stiffness, characteristic slip distance, direct velocity and time dependent state effects) are tested separately. Our results indicate that earthquake triggering is controlled mainly by the onset time, size and duration of the triggering signal but not much sensitive to the signal frequency. In terms of fault system parameters, the fault stiffness and the direct velocity effect are the critical parameters in triggering processes. Among the tested RSF laws, “Ruina” law is more sensitive than “Dieterich” law to both static and dynamic changes and “Perrin” is apparently the most sensitive law to dynamic changes. Especially, when the triggering onset time is close to an unperturbed failure time (future earthquake), dynamic changes result the largest clock advancement, otherwise, static stress changes are substantially more effective. In the next step, realistic models will be established to simulate the effect of the recent (26 September 2019) Marmara earthquake with Mw=5.7 on the locked Kumburgaz fault segment of the North Anatolian Fault Zone. The triggering earthquake will be simulated by combining the static stress change computed via Coulomb law and the dynamic effects using ground motions recorded at broadband seismic stations within similar distances. Outcomes will help us to better understand the effects of static and dynamic changes on the seismic cycle of the Kumburgaz fault segment, which is expected to break soon with a possibly big earthquake causing damage at the metropolitan area of Istanbul in Turkey.</p>

A New Technique to Calculate Earthquake Stress Transfer and to Probe the Physics of Aftershocks

2020 ◽  
Vol 110 (2) ◽  
pp. 863-873 ◽  
Author(s):  
Margarita Segou ◽  
Tom Parsons
Keyword(s):  
Stress Reduction ◽  
Regional Scale ◽  
Stress Transfer ◽  
The United States ◽  
Physical Principle ◽  
Static Stress ◽  
Stress Change ◽  
Earthquake Triggering ◽  
Triggered Earthquakes ◽  
Stress Changes

ABSTRACT Coseismic stress changes have been the primary physical principle used to explain aftershocks and triggered earthquakes. However, this method does not adequately forecast earthquake rates and diverse rupture populations when subjected to formal testing. We show that earthquake forecasts can be impaired by assumptions made in physics-based models such as the existence of hypothetical optimal faults and regional scale invariability of the stress field. We compare calculations made under these assumptions along with different realizations of a new conceptual triggering model that features a complete assay of all possible ruptures. In this concept, there always exists a set of theoretical planes that has positive failure stress conditions under a combination of background and coseismic static stress change. In the Earth, all of these theoretical planes may not exist, and if they do, they may not be ready to fail. Thus, the actual aftershock plane may not correspond to the plane with the maximum stress change value. This is consistent with observations that mainshocks commonly activate faults with exotic orientations and rakes. Our testing ground is the M 7.2, 2010 El Mayor–Cucapah earthquake sequence that activated multiple diverse fault populations across the United States–Mexico border in California and Baja California. We carry out a retrospective test involving 748 M≥3.0 triggered earthquakes that occurred during a 3 yr period after the mainshock. We find that a probabilistic expression of possible aftershock planes constrained by premainshock rupture patterns is strongly favored (89% of aftershocks consistent with static stress triggering) versus an optimal fault implementation (35% consistent). Results show that coseismic stress change magnitudes do not necessarily control earthquake triggering, instead we find that the summed background stress and coseismic stress change promotes diverse ruptures. Our model can thus explain earthquake triggering in regions where optimal plane mapping shows coseismic stress reduction.

Static stress changes and earthquake triggering during the 1954 Fairview Peak and Dixie Valley earthquakes, central Nevada

1997 ◽  
Vol 87 (3) ◽  
pp. 521-527
Author(s):  
S. J. Caskey ◽  
S. G. Wesnousky
Keyword(s):  
Three Dimensional ◽  
Field Studies ◽  
Static Stress ◽  
Earthquake Triggering ◽  
Three Dimensional Model ◽  
Surface Displacements ◽  
Stress Changes ◽  
Northward Propagation ◽  
Dixie Valley ◽  
Element Approach

Abstract The 16 December 1954 Dixie Valley (MS 6.8) earthquake followed the Fairview Peak (MS 7.2) earthquake by only 4 min and 20 sec. A three-dimensional model of the two dip-slip fault systems based on recent detailed field studies shows the ruptures were separated by a 6-km step in surface trace. A boundary-element approach shows that the static stress changes imposed by rupture of the Fairview Peak earthquake are in the correct sense to explain the northward propagation of faulting along four distinct faults that comprise the Fairview Peak earthquake and the subsequent triggering of the Dixie Valley earthquake. The location of rupture end points at sites where static stresses change sign is also used to suggest that static stress changes may play a role in controlling the extent of fault ruptures. We also observe that the largest coseismic surface displacements tend to correlate with those sections of the faults showing the largest positive stress change from preceding ruptures.

scholarly journals EARTHQUAKE TRIGGERING EFFECT SCENARIOS DURING THE 2014 SEQUENCE IN CEPHALONIA AND 2015 EARTHQUAKE IN LEFKADA BROADER AREAS, IONIAN SEA, GREECE

2017 ◽  
Vol 50 (1) ◽  
pp. 540
Author(s):  
S. Sboras ◽  
A. Chatzipetros ◽  
S. Pavlides ◽  
V. Karastathis ◽  
G. Papadopoulos
Keyword(s):  
Cumulative Effects ◽  
Fault System ◽  
Ionian Sea ◽  
Coulomb Stress Change ◽  
Earthquake Triggering ◽  
Fault Interaction ◽  
Local Complex ◽  
Complex Fault ◽  
Stress Changes ◽  
Complex Distribution

In this paper we defined the local complex fault system of the Cephalonia three strongest earthquakes (Mw6.1, Mw5.3 and Mw6.0) of the January-February 2014 sequence and the Lefkada mainshock (Mw6.4) on November 17, 2015, in order to investigate the fault interaction i) within the 2014 sequence, ii) between the 2014 sequence and the fault that produced the 2015 Lefkada event, and iii) the cumulative effects of all Cephalonia and Lefkada strong events on other neighbouring faults, by calculating the static stress changes. The Coulomb stress change calculations suggest a complex distribution pattern on most of the cases, with only exceptions the F4 fault (Lefkada earthquake), which seems to be barely loaded with stress after the Cephalonia 2014 events, and the “Assos-Skala” fault, which seems to be stress relieved after all Caphalonia 2014 and Lefkada 2015 events.

scholarly journals Earthquake triggering model based on normal-stress-dependent Nagata law: application to the 2016 Mie offshore earthquake

2020 ◽  
Vol 72 (1) ◽  
Author(s):  
Shingo Yoshida ◽  
Takuto Maeda ◽  
Naoyuki Kato
Keyword(s):  
Shear Stress ◽  
Normal Stress ◽  
Static Stress ◽  
Stress Dependence ◽  
Slow Slip ◽  
Earthquake Triggering ◽  
Slow Slip Events ◽  
Stress Changes ◽  
Stress Dependent ◽  
Offshore Earthquake

Abstract We propose a normal-stress-dependent Nagata law. Nagata et al. (J Geophys Res 117:B02314, 2012) revised the rate- and state-dependent friction law by introducing the shear stress dependence. We further extended the Nagata law by incorporating the normal stress dependence obtained by Linker and Dieterich (J Geophys Res 97:4923–4940, 1992). We performed numerical simulations of earthquake triggering by assuming the extended Nagata law. In the case of repeated earthquakes, we applied dynamic Coulomb failure function (CFF) perturbation due to normal or shear stress changes. CFF perturbation increased the slip velocity after the cessation of perturbation, relative to that of the repeated events without triggering. This leads to dynamic earthquake triggering for certain perturbation amplitudes with time to instability of 0 to several tens of days. In addition, triggering potential of the static CFF jump (ΔCFFs) was investigated. Static stress perturbation has a higher triggering potential than dynamic stress perturbation for the same magnitude of CFF. The equivalent ΔCFFeq is evaluated for dynamic perturbation that results in a triggering potential approximately the same as in the case of static stress perturbation if ΔCFFs = ΔCFFeq. We calculated ΔCFFeq on the interface of the Philippine Sea plate for the Mie offshore earthquake, which occurred around the Nankai Trough on April 1, 2016, using OpenSWPC. The results shows that ΔCFFeq is large around the trough, where slow slip events followed the Mie earthquake, suggesting that a large ΔCFFeq may have triggered slow slip events.

scholarly journals Earthquake static stress transfer in the 2013 Gulf of Valencia (Spain) seismic sequence

Solid Earth ◽  
2017 ◽  
Vol 8 (5) ◽  
pp. 857-882 ◽  
Author(s):  
Lluís Saló ◽  
Tànit Frontera ◽  
Xavier Goula ◽  
Luis G. Pujades ◽  
Alberto Ledesma
Keyword(s):  
Stress Transfer ◽  
Mediterranean Coast ◽  
Static Stress ◽  
Earthquake Triggering ◽  
Underground Gas Storage ◽  
Focal Mechanism Solutions ◽  
Stress Changes ◽  
Coulomb Failure ◽  
As Stress

Abstract. On 24 September 2013, an Ml 3.6 earthquake struck in the Gulf of Valencia (Spain) near the Mediterranean coast of Castelló, roughly 1 week after gas injections conducted in the area to develop underground gas storage had been halted. The event, felt by the nearby population, led to a sequence build-up of felt events which reached a maximum of Ml 4.3 on 2 October.Here, we study the role of static stress transfer as an earthquake-triggering mechanism during the main phase of the sequence, as expressed by the eight felt events. By means of the Coulomb failure function, cumulative static stress changes are quantified on fault planes derived from focal mechanism solutions (which act as both source and receiver faults) and on the previously mapped structures in the area (acting only as stress receivers in our modeling). Results suggest that static stress transfer played a destabilizing role and point towards an SE-dipping structure underlying the reservoir (or various with analogous geometry) that was most likely activated during the sequence. One of the previously mapped faults could be geometrically compatible, yet our study supports deeper sources. Based on this approach, the influence of the main events in the occurrence of future and potentially damaging earthquakes in the area would not be significant.

Static stress changes associated with normal faulting earthquakes in South Balkan area

2006 ◽  
Vol 96 (5) ◽  
pp. 911-924 ◽  
Author(s):  
E. Papadimitriou ◽  
V. Karakostas ◽  
M. Tranos ◽  
B. Ranguelov ◽  
D. Gospodinov
Keyword(s):  
Static Stress ◽  
Normal Faulting ◽  
Stress Changes ◽  
Balkan Area

Study on the Dynamic Changes in Chest CT Findings of COVID-19 Rehabilitated Patients

2020 ◽  
pp. 1-7
Keyword(s):  
Disease Progression ◽  
Onset Time ◽  
Ground Glass Opacity ◽  
Chest Ct ◽  
Ground Glass ◽  
Dynamic Changes ◽  
Course Of Disease ◽  
Pleural Thickening ◽  
Ct Findings ◽  
Interlobular Septal Thickening

Objective: To study the dynamic changes in CT findings in COVID-19 (coronavirus disease-19, COVID-19) rehabilitated patients. Methods: A total of 148 chest CT images of 37 patients with COVID-19 were collected. In the first 21 days of the course of disease, 7 stages were performed every 3 days, and the eighth stage was performed after 21 days. Results: In the first chest CT examination, 19 cases were ground glass opacity, and 18 cases were high-density shadows with consolidation. The lesion shape was flaky and patchy in 33 cases. The percentage of consolidation, air bronchogram, fiber cord, interlobular septal thickening, subpleural line and pleural thickening were the highest on days 4-6, 7-9, 7-9, 10-12, 19-21 and 19-21, respectively. The highest percentage of disease progression was 80.00% on days 4-6, and then the percentage of disease progression gradually decreased with the extension of the onset time. The percentage of patients with improvement gradually increased from days 4-6, reaching 83.33% on days 16-18 and 100.00% on day 21. The percentage of lesion range enlargement and density increase was the highest on days 4-6, both of which were 60.00%，Then the percentage of both decreased gradually. The percentage of patients with lesion range reduction and density absorption dilution increased gradually with the onset time. There was no obvious regularity in the number of lesions. Conclusion: Patients with COVID-19 have regular changes in their lung conditions.

Fluid-induced aseismic fault slip outpaces pore-fluid migration

Science ◽  
2019 ◽  
Vol 364 (6439) ◽  
pp. 464-468 ◽  
Author(s):  
Pathikrit Bhattacharya ◽  
Robert C. Viesca
Keyword(s):  
Pore Fluid ◽  
Fluid Injection ◽  
Fluid Migration ◽  
Aseismic Slip ◽  
Earthquake Triggering ◽  
Effective Normal Stress ◽  
Shear Rupture ◽  
Stress Changes ◽  
Slip History ◽  
Rupture Model

Earthquake swarms attributed to subsurface fluid injection are usually assumed to occur on faults destabilized by increased pore-fluid pressures. However, fluid injection could also activate aseismic slip, which might outpace pore-fluid migration and transmit earthquake-triggering stress changes beyond the fluid-pressurized region. We tested this theoretical prediction against data derived from fluid-injection experiments that activated and measured slow, aseismic slip on preexisting, shallow faults. We found that the pore pressure and slip history imply a fault whose strength is the product of a slip-weakening friction coefficient and the local effective normal stress. Using a coupled shear-rupture model, we derived constraints on the hydromechanical parameters of the actively deforming fault. The inferred aseismic rupture front propagates faster and to larger distances than the diffusion of pressurized pore fluid.

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