Detailed analysis of spatiotemporal variations of the stress field orientation along the Izmit-Düzce rupture in NW Turkey from inversion of first-motion polarity data

Ickrath, Michèle; Bohnhoff, Marco; Dresen, Georg; Martínez‐Garzón, Patricia; Bulut, Fatih; Kwiatek, Grzegorz; Germer, Oliver

doi:10.1093/gji/ggv273

Cited by 20 publications

(25 citation statements)

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“…Aftershock recordings provided information for detailed studies of the seismotectonic setting after the Izmit and Düzce mainshocks [ Bohnhoff et al , ; Bulut et al , ; Bohnhoff et al , Crustal response to spatiotemporal variations of coseismic slip along the combined 1999 Izmit‐Düzce rupture, submitted to Tectonophysics , 2015]. The results in part also documented a significant rotation of the local stress tensor [ Ickrath et al , , ] and substantial nondouble components [ Stierle et al , , ] below the Akyazi Basin within weeks following the mainshock. The Karadere Segment is located between the Akyazi and Düzce releasing bends and is a steeply (~67°) north dipping strike‐slip fault [ Bulut et al , ], reflecting mostly right‐lateral strike‐slip aftershocks in general correspondence with the regional stress field [ Bohnhoff et al , ; Görgün et al , ].…”

Section: Study Area and Datamentioning

confidence: 99%

Bimaterial interfaces at the Karadere segment of the North Anatolian Fault, northwestern Turkey

2016

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We image velocity contrast (bimaterial) interfaces along the Karadere Fault of the North Anatolian Fault Zone, toward the eastern part of the 1999 Izmit Mw 7.4 rupture in NW Turkey, using waveforms recorded by a local seismic network. Applying an automatic procedure for identification and picking of fault zone head waves (FZHW) and direct P arrivals, and manually revising the picks through particle motion analysis, we identify two different groups of FZHW as well as fault zone reflected waves (FZRW). The first group of FZHW has a moveout with respect to the direct P arrivals with distance traveled along the fault, indicating a deep bimaterial interface down to the base of the seismogenic crust with an average velocity contrast of ~3.4%. The second group of FZHW has a constant time difference from the direct P arrivals and is associated with a shallow local interface bounding a low‐velocity damage zone or basin structure that extends to a depth of 4–5 km. While the first group of FZHW exists on the slower crustal block, the second group of FZHW and the FZRW are present generally on both sides of the fault. These phases add to the richness and complexity of the early P waveforms observed at stations close to a large fault. The relatively low velocity contrast across the Karadere Fault compared to values to the west may have helped stopping the Izmit rupture.

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Section: Study Area and Datamentioning

confidence: 99%

Bimaterial interfaces at the Karadere segment of the North Anatolian Fault, northwestern Turkey

2016

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“…If a sufficiently high number of seismic events with focal mechanisms is available in a spatially confined area over a certain time period, advanced stress inversion techniques even allow for determining temporal variations of the stress state [ Hardebeck and Michael , ; Martínez‐Garzón et al , ] or the 3‐D spatial distribution [ Martínez‐Garzón et al , ]. Thereby, temporal local rotations of the stress tensor have been observed as a physical response of the rock formation to large tectonic earthquakes [ Hardebeck and Hauksson , ; Bohnhoff et al , ; Ickrath et al , ]. Typically, these coseismically introduced stress rotations decrease within weeks or months back to pre–main shock orientations to a large extent [ Hardebeck , ].…”

Section: Introductionmentioning

confidence: 99%

Estimation of the differential stress from the stress rotation angle in low permeable rock

Ziegler

Heidbach

Zang

et al. 2017

Geophysical Research Letters

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Rotations of the principal stress axes are observed as a result of fluid injection into reservoirs. We use a generic, fully coupled 3‐D thermo‐hydro‐mechanical model to investigate systematically the dependence of this stress rotation on different reservoir properties and injection scenarios. We find that permeability, injection rate, and initial differential stress are the key factors, while other reservoir properties only play a negligible role. In particular, we find that thermal effects do not significantly contribute to stress rotations. For reservoir types with usual differential stress and reservoir treatment the occurrence of significant stress rotations is limited to reservoirs with a permeability of less than approximately 10−12 m2. Higher permeability effectively prevents stress rotations to occur. Thus, according to these general findings, the observed principal stress axes rotation can be used as a proxy of the initial differential stress provided that rock permeability and fluid injection rate are known a priori.

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“…However, the crustal stress field controlling fault growth may change locally and in time. For example, studies from major faults as the San Andreas Fault, USA, [ Hardebeck and Hauksson , ] or the North Anatolian Fault Zone, Turkey, [ Örgülü , ; Ickrath et al ., ] presented spatiotemporal transients of regional stresses using focal mechanisms and stress inversion. Also, large angles (>50°) between fault planes and maximum horizontal stress orientation S HMAX have been found at major fault zones [e.g., Hardebeck and Hauksson , ; Townend et al ., ; Martínez‐Garzón et al ., ] suggesting low‐frictional fault strength [ Zoback et al ., ].…”

Section: Introductionmentioning

confidence: 99%

Impact of fluid injection on fracture reactivation at The Geysers geothermal field

et al. 2016

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We analyze the spatiotemporal distribution of fault geometries from seismicity induced by fluid injection at The Geysers geothermal field. The consistency of these faults with the local stress field is investigated using (1) the fault instability coefficient I comparing the orientation of a fault with the optimal orientation for failure in the assumed stress field and (2) the misfit angle β between slip vectors observed from focal mechanisms and predicted from stress tensor. A statistical approach is applied to calculate the most likely fault instabilities considering the uncertainties from focal mechanisms and stress inversion. We find that faults activated by fluid injection may display a broad range in orientations. About 72% of the analyzed seismicity occurs on faults with favorable orientation for failure with respect to the stress field. However, a number of events are observed either to occur on severely misoriented faults or to slip in a different orientation than predicted from stress field. These events mostly occur during periods of high injection rates and are located in proximity to the injection wells. From the stress inversion, the friction coefficient providing the largest overall instability is μ = 0.5. About 91% of the events are activated with an estimated excess pore pressure <10 MPa, in agreement with previous models considering the combined effect of thermal and poroelastic stress changes from fluid injection. Furthermore, high seismic activity and largest magnitudes occur on favorably oriented faults with large instability coefficients and low slip misfit angles.

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Detailed analysis of spatiotemporal variations of the stress field orientation along the Izmit-Düzce rupture in NW Turkey from inversion of first-motion polarity data

Abstract: (2015): Detailed analysis of spatiotemporal variations of the stress field orientation along the Izmit-Düzce rupture in NW Turkey from inversion of first-motion polarity data.

Cited by 20 publications

References 49 publications

Bimaterial interfaces at the Karadere segment of the North Anatolian Fault, northwestern Turkey

Bimaterial interfaces at the Karadere segment of the North Anatolian Fault, northwestern Turkey

Estimation of the differential stress from the stress rotation angle in low permeable rock

Impact of fluid injection on fracture reactivation at The Geysers geothermal field

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