STRESS EVOLUTION ONTO MAJOR FAULTS IN MYGDONIA BASIN

Stress transfer due to the coseismic slip of strong earthquakes, along with fault population characteristics, constitutes one of the most determinative factors for evaluating the occurrence of future events. The stress Coulomb (ΔCFF) evolutionary model in Mygdonia basin (N.Greece) is based on the coseismic changes of strong earthquakes (M≥6.0) from 1677 until 1978 and the tectonic loading expressed with slip rates along major faults. In the view of stress transfer mechanisms, ΔCFF is also calculated onto fault planes, along with the segmented fault zone from Thessaloniki to Gerakarou and N.Apollonia (TG-NAp FZ). Normal fault segments bound the basin from the south and currently compose the most active neotectonic zone. The association of the spatial distribution of seismicity (2000-2014) with the stress enhanced areas is also investigated. Results demonstrate that the earthquake locations are strongly influenced by the stress transfer from past strong earthquakes and their focal properties. Since the stress build-up occurs fast, results are discussed in terms of hazard assessment by defining potential locations for future events.

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Complex Slip Distribution of the 2021 Mw 7.4 Maduo, China, Earthquake: An Event Occurring on the Slowly Slipping Fault

Seismological Research Letters ◽

10.1785/0220210226 ◽

2021 ◽

Author(s):

Rumeng Guo ◽

Hongfeng Yang ◽

Yu Li ◽

Yong Zheng ◽

Lupeng Zhang

Keyword(s):

Slip Rate ◽

Slip Distribution ◽

Seismic Gap ◽

Seismogenic Fault ◽

Coseismic Slip ◽

Slip Rates ◽

Kunlun Mountain ◽

Coulomb Failure ◽

Main Fault ◽

Large Earthquakes

Abstract The 21 May 2021 Maduo earthquake occurred on the Kunlun Mountain Pass–Jiangcuo fault (KMPJF), a seismogenic fault with no documented large earthquakes. To probe its kinematics, we first estimate the slip rates of the KMPJF and Tuosuo Lake segment (TLS, ∼75 km north of the KMPJF) of the East Kunlun fault (EKLF) based on the secular Global Positioning System (GPS) data using the Markov chain Monte Carlo method. Our model reveals that the slip rates of the KMPJF and TLS are 1.7 ± 0.8 and 7.1 ± 0.3 mm/yr, respectively. Then, we invert high-resolution GPS and Interferometric Synthetic Aperture Radar observations to decipher the fault geometry and detailed coseismic slip distribution associated with the Maduo earthquake. The geometry of the KMPFJ significantly varies along strike, composed of five fault subsegments. The most slip is accommodated by two steeply dipping fault segments, with the patch of large sinistral slip concentrated in the shallow depth on a simple straight structure. The released seismic moment is ∼1.5×1020 N·m, equivalent to an Mw 7.39 event, with a peak slip of ∼9.3 m. Combining the average coseismic slip and slip rate of the main fault, an earthquake recurrence period of ∼1250−400+1120 yr is estimated. The Maduo earthquake reminds us to reevaluate the potential of seismic gaps where slip rates are low. Based on our calculated Coulomb failure stress, the Maduo earthquake imposes positive stress on the Maqin–Maqu segment of the EKLF, a long-recognized seismic gap, implying that it may accelerate the occurrence of the next major event in this region.

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Seismic Activity of the Manisa Fault Zone in Western Turkey Constrained by Cosmogenic 36Cl Dating

Geosciences ◽

10.3390/geosciences11110451 ◽

2021 ◽

Vol 11 (11) ◽

pp. 451

Author(s):

Nasim Mozafari ◽

Çağlar Özkaymak ◽

Dmitry Tikhomirov ◽

Susan Ivy-Ochs ◽

Vasily Alfimov ◽

...

Keyword(s):

Fault Zone ◽

Normal Fault ◽

Vertical Displacement ◽

Historical Records ◽

Western Turkey ◽

Slip Rates ◽

Vertical Displacements ◽

Surface Ruptures ◽

Fault Scarps ◽

Calculated Average

This study reports on the cosmogenic 36Cl dating of two normal fault scarps in western Turkey, that of the Manastır and Mugırtepe faults, beyond existing historical records. These faults are elements of the western Manisa Fault Zone (MFZ) in the seismically active Gediz Graben. Our modeling revealed that the Manastır fault underwent at least two surface ruptures at 3.5 ± 0.9 ka and 2.0 ± 0.5 ka, with vertical displacements of 3.3 ± 0.5 m and 3.6 ± 0.5 m, respectively. An event at 6.5 ± 1.6 ka with a vertical displacement of 2.7 ± 0.4 m was reconstructed on the Mugırtepe fault. We attribute these earthquakes to the recurring MFZ ruptures, when also the investigated faults slipped. We calculated average slip rates of 1.9 and 0.3 mm yr−1 for the Manastır and Mugırtepe faults, respectively.

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Tectonic Geomorphology and Paleoseismology of the Sharkhai fault: a new source of seismic hazard for Ulaanbaatar (Mongolia)

10.5194/se-2021-91 ◽

2021 ◽

Author(s):

Abeer Al-Ashkar ◽

Antoine Schlupp ◽

Matthieu Ferry ◽

Ulziibat Munkhuu

Keyword(s):

Seismic Hazard ◽

Scaling Laws ◽

Active Faults ◽

Seismic Hazard Assessment ◽

Capital City ◽

Tectonic Geomorphology ◽

Time Interval ◽

Coseismic Slip ◽

Slip Rates ◽

Large Earthquakes

Abstract. We present new constraints from tectonic geomorphology and paleoseismology along the newly discovered Sharkhai fault near the capital city of Mongolia. Detailed observations from high resolution Pleiades satellite images and field investigations allowed us to map the fault in detail, describe its geometry and segmentation, characterize its kinematics, and document its recent activity and seismic behavior (cumulative displacements and paleoseismicity). The Sharkhai fault displays a surface length of ~40 km with a slightly arcuate geometry, and a strike ranging from N42° E to N72° E. It affects numerous drainages that show left-lateral cumulative displacements reaching 57 m. Paleoseismic investigations document the faulting and deposition record for the last ~3000 yr and reveal that the penultimate earthquake (PE) occurred between 1515 ± 90 BC and 945 ± 110 BC and the most recent event (MRE) occurred after 860 ± 85 AD. The resulting time interval of 2080 ± 470 years is the first constraint on the Sharkhai fault for large earthquakes. On the basis of our mapping of the surface rupture and the resulting segmentation analysis, we propose two possible scenarios for large earthquakes with likely magnitudes between 6.4 ± 0.2 and 7.1 ± 0.2. Furthermore, we apply scaling laws to infer coseismic slip values and derive preliminary estimates of long-term slip rates between 0.2 ± 0.2 and 1.0 ± 0.5 mm/y. Finally, we propose that these original observations and results from a newly discovered fault should be taken into account for the seismic hazard assessment for the city of Ulaanbaatar and help build a comprehensive model of active faults in that region.

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Identification of Paleoearthquakes and Coseismic Slips on a Normal Fault Using High-Precision Quantitative Morphology: Application to the Jiaocheng Fault in the Shanxi Rift, China

Lithosphere ◽

10.2113/2021/2550879 ◽

2021 ◽

Vol 2021 (Special 2) ◽

Author(s):

Junjie Zou ◽

Honglin He ◽

Yusuke Yokoyama ◽

Adam D. Sproson ◽

Yoshiki Shirahama ◽

...

Keyword(s):

Active Faults ◽

Normal Fault ◽

Seismic Events ◽

Quantitative Morphology ◽

Coseismic Slip ◽

Slip History ◽

Absolute Dating ◽

Future Work ◽

Shanxi Rift

Abstract The quantitative morphology of bedrock fault surfaces combined with aerial surveys and field identification is a useful approach to identify paleoearthquakes, obtain coseismic slips, and evaluate the seismogenic capacity of active faults in bedrock areas where traditional trenching methods are not applicable. Here, we report a case study of the Jiaocheng Fault (JCF) in the Shanxi Rift, China. Although several studies have been conducted on the JCF, its coseismic slip history and seismogenic capacity are still unclear. To address these problems, we investigated two bedrock fault surfaces, Sixicun (SXC) and Shanglanzhen (SLZ), on the JCF’s northern segment using quantitative morphological analysis together with aerial and field surveys. Quantitative fractal analysis based on the isotropic empirical variogram and moving window shows that both bedrock fault surfaces have the characteristics of vertical segmentation, which is likely due to periodic earthquakes, the coseismic slip of which can be determined by the height of the segments. Three seismic events at SXC, with a coseismic vertical slip of 1.74, 1.65, and 1.99 m, and three seismic events at SLZ, with a coseismic vertical slip of 1.32, 2.35, and 1.88 m, are identified. Compared with the previous studies, these three seismic events may occur in the Holocene, but it requires absolute dating ages to support, which is also the focus of our future work. Considering the seismologic capability (M>7.5) and the relationship between the recurrence interval of ~2.6 kyr and elapsed time of more than 3 kyr, the seismic hazard of the northern and middle segments of the JCF requires immediate attention.

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Lower Portion Rupture of a Thrust Fault during the 2017 Mw 6.3 Jinghe Earthquake: Implications to Seismic Hazards in the Tian Shan Region

Seismological Research Letters ◽

10.1785/0220200295 ◽

2021 ◽

Author(s):

Zongkai Hu ◽

Tao Li ◽

Jessica Thompson Jobe ◽

Xiaoping Yang

Keyword(s):

Land Surface ◽

Geometric Model ◽

Interferometric Synthetic Aperture Radar ◽

Coseismic Slip ◽

Surface Mapping ◽

Strong Earthquakes ◽

Fault Bend ◽

Large Earthquakes ◽

Rupture Pattern ◽

Tian Shan

Abstract The 2017 Mw 6.3 Jinghe earthquake represents one of the few large earthquakes that are well recorded by seismic instruments and Interferometric Synthetic Aperture Radar (InSAR) observations in the seismically active Tian Shan region. In this study, we use the rupture fault solution (dip, dip direction, and slip sense) from seismologic and InSAR results, along with analysis of our collected surface mapping data, to determine the subsurface fault-plane geometry of the seismogenic Jinghenan fault. This geometric model, integrated with the coseismic slip distribution from seismologic and InSAR data, reveals that: (1) the Jinghenan fault extends downward from the land surface at a dip of ∼46° S (upper ramp), then bends to ∼42° S (lower ramp) at the depth of 9–13 km; (2) the coseismic rupture is confined within the Jinghenan lower ramp, and its upper limitation is approximately coincident with the fault-bend location. This coseismic rupture pattern and seismic behavior can be broadened to other active thrust faults within the Tian Shan, suggesting that, during moderate-strong earthquakes, such faults may only rupture partially in the down-dip extension, and the unruptured fault portion remains to pose high-seismic risk in the future.

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A Framework for Stress Transfer Mechanisms in Connective Tissues

IFMBE Proceedings - 4th Kuala Lumpur International Conference on Biomedical Engineering 2008 ◽

10.1007/978-3-540-69139-6_94 ◽

2008 ◽

pp. 370-373

Author(s):

K. L. Goh ◽

C. Yang ◽

H. J. Wang

Keyword(s):

Stress Transfer ◽

Connective Tissues ◽

Transfer Mechanisms

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Evolution of Stress Transfer Mechanisms During Mechanical Interaction Between Hydraulic Fractures and Natural Fractures

Hydraulic Fracturing and Well Stimulation ◽

10.1002/9781119555711.ch2 ◽

2019 ◽

pp. 35-51

Author(s):

Birendra Jha

Keyword(s):

Stress Transfer ◽

Hydraulic Fractures ◽

Natural Fractures ◽

Mechanical Interaction ◽

Transfer Mechanisms

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Coulomb stress transfer and fault interaction over millennia on non-planar active normal faults: the Mw 6.5–5.0 seismic sequence of 2016–2017, central Italy

Geophysical Journal International ◽

10.1093/gji/ggx213 ◽

2017 ◽

Vol 210 (2) ◽

pp. 1206-1218 ◽

Cited By ~ 32

Author(s):

Zoe K. Mildon ◽

Gerald P. Roberts ◽

Joanna P. Faure Walker ◽

Francesco Iezzi

Keyword(s):

Main Shock ◽

Central Italy ◽

Stress Transfer ◽

Historical Record ◽

Normal Faults ◽

Coulomb Stress ◽

Seismic Sequence ◽

Fault Interaction ◽

Slip Rates ◽

Stress Changes

Abstract In order to investigate the importance of including strike-variable geometry and the knowledge of historical and palaeoseismic earthquakes when modelling static Coulomb stress transfer and rupture propagation, we have examined the August–October 2016 A.D. and January 2017 A.D. central Apennines seismic sequence (Mw 6.0, 5.9, 6.5 in 2016 A.D. (INGV) and Mw 5.1, 5.5, 5.4, 5.0 in 2017 A.D. (INGV)). We model both the coseismic loading (from historical and palaeoseismic earthquakes) and interseismic loading (derived from Holocene fault slip-rates) using strike-variable fault geometries constrained by fieldwork. The inclusion of the elapsed times from available historical and palaeoseismological earthquakes and on faults enables us to calculate the stress on the faults prior to the beginning of the seismic sequence. We take account the 1316–4155 yr elapsed time on the Mt. Vettore fault (that ruptured during the 2016 A.D. seismic sequence) implied by palaeoseismology, and the 377 and 313 yr elapsed times on the neighbouring Laga and Norcia faults respectively, indicated by the historical record. The stress changes through time are summed to show the state of stress on the Mt. Vettore, Laga and surrounding faults prior to and during the 2016–2017 A.D. sequence. We show that the build up of stress prior to 2016 A.D. on strike-variable fault geometries generated stress heterogeneities that correlate with the limits of the main-shock ruptures. Hence, we suggest that stress barriers appear to have control on the propagation and therefore the magnitudes of the main-shock ruptures.

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