scholarly journals Variable normal-fault rupture behavior, northern Lost River fault zone, Idaho, USA

Geosphere ◽  
2019 ◽  
Vol 15 (6) ◽  
pp. 1869-1892 ◽  
Author(s):  
Christopher B. DuRoss ◽  
Michael P. Bunds ◽  
Ryan D. Gold ◽  
Richard W. Briggs ◽  
Nadine G. Reitman ◽  
...  
Keyword(s):  
Fault Zone ◽  
Structural Complexity ◽  
Normal Fault ◽  
Vertical Displacement ◽  
Fault Rupture ◽  
Surface Displacements ◽  
Surface Models ◽  
History Of ◽  
Warm Springs ◽  
The Moment

Abstract The 1983 Mw 6.9 Borah Peak earthquake generated ∼36 km of surface rupture along the Thousand Springs and Warm Springs sections of the Lost River fault zone (LRFZ, Idaho, USA). Although the rupture is a well-studied example of multisegment surface faulting, ambiguity remains regarding the degree to which a bedrock ridge and branch fault at the Willow Creek Hills influenced rupture progress. To explore the 1983 rupture in the context of the structural complexity, we reconstruct the spatial distribution of surface displacements for the northern 16 km of the 1983 rupture and prehistoric ruptures in the same reach of the LRFZ using 252 vertical-separation measurements made from high-resolution (5–10-cm-pixel) digital surface models. Our results suggest the 1983 Warm Springs rupture had an average vertical displacement of ∼0.3–0.4 m and released ∼6% of the seismic moment estimated for the Borah Peak earthquake and <12% of the moment accumulated on the Warm Springs section since its last prehistoric earthquake. The 1983 Warm Springs rupture is best described as the moderate-displacement continuation of primary rupture from the Thousand Springs section into and through a zone of structural complexity. Historical and prehistoric displacements show that the Willow Creek Hills have impeded some, but not all ruptures. We speculate that rupture termination or penetration is controlled by the history of LRFZ moment release, displacement, and rupture direction. Our results inform the interpretation of paleoseismic data from near zones of normal-fault structural complexity and demonstrate that these zones may modulate rather than impede rupture displacement.

Holocene Paleoseismology of the Steamboat Mountain Site: Evidence for Full-Length Rupture of the Teton Fault, Wyoming

2020 ◽  
Author(s):  
Christopher B. DuRoss ◽  
Mark S. Zellman ◽  
Glenn D. Thackray ◽  
Richard W. Briggs ◽  
Ryan D. Gold ◽  
...  
Keyword(s):  
Normal Fault ◽  
Vertical Displacement ◽  
Alluvial Fan ◽  
Full Length ◽  
Fault Rupture ◽  
Partial Length ◽  
Mountain Site ◽  
Vertical Displacements ◽  
History Of ◽  
Lateral Extent

ABSTRACT The 72-km-long Teton fault in northwestern Wyoming is an ideal candidate for reconstructing the lateral extent of surface-rupturing earthquakes and testing models of normal-fault segmentation. To explore the history of earthquakes on the northern Teton fault, we hand-excavated two trenches at the Steamboat Mountain site, where the east-dipping Teton fault has vertically displaced west-sloping alluvial-fan surfaces. The trenches exposed glaciofluvial, alluvial-fan, and scarp-derived colluvial sediments and stratigraphic and structural evidence of two surface-rupturing earthquakes (SM1 and SM2). A Bayesian geochronologic model for the site includes three optically stimulated luminescence ages (∼12–17  ka) for the glaciofluvial units and 16 radiocarbon ages (∼1.2–8.6  ka) for the alluvial-fan and colluvial units and constrains SM1 and SM2 to 5.5±0.2  ka, 1σ (5.2–5.9 ka, 95%) and 9.7±0.9  ka, 1σ (8.5–11.5 ka, 95%), respectively. Structural, stratigraphic, and geomorphic relations yield vertical displacements for SM1 (2.0±0.6  m, 1σ) and SM2 (2.0±1.0  m, 1σ). The Steamboat Mountain paleoseismic chronology overlaps temporally with earthquakes interpreted from previous terrestrial and lacustrine paleoseismic data along the fault. Integrating these data, we infer that the youngest Teton fault rupture occurred at ∼5.3  ka, generated 1.7±1.0  m, 1σ of vertical displacement along 51–70 km of the fault, and had a moment magnitude (Mw) of ∼7.0–7.2. This rupture was apparently unimpeded by structural complexities along the Teton fault. The integrated chronology permits a previous full-length rupture at ∼10  ka and possible partial ruptures of the fault at ∼8–9  ka. To reconcile conflicting terrestrial and lacustrine paleoseismic data, we propose a hypothesis of alternating full- and partial-length ruptures of the Teton fault, including Mw∼6.5–7.2 earthquakes every ∼1.2  ky. Additional paleoseismic data for the northern and central sections of the fault would serve to test this bimodal rupture hypothesis.

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

Geosciences ◽  
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.

Hayward fault slippage in the Irvington-Niles districts of Fremont, California

1966 ◽  
Vol 56 (2) ◽  
pp. 257-279 ◽  
Author(s):  
Lloyd S. Cluff ◽  
Karl V. Steinbrugge
Keyword(s):  
Fault Zone ◽  
Time History ◽  
Wide Band ◽  
Strong Earthquakes ◽  
The Past ◽  
Parallel Lines ◽  
History Of ◽  
Surface Ruptures ◽  
Warm Springs

abstract Right lateral slippage on the Hayward fault has faken place in the Irvington and Niles districts of Fremont since the well known 1868 Hayward earthquake which produced surface ruptures from San Leandro to Warm Springs. This post-1868 movement has been occurring without being identified with strong earthquakes. Structures and railroads crossing the Hayward fault in the area under study date back to 1866. Fault slippage can be observed at ten separate locations along the strike of the Hayward fault in the Irvington-Niles districts of Fremont, California. One location predates the 1868 earthquake. There is no evidence for parallel lines of fault slippage within the approximately 200-foot wide fault zone. The slippage appears to have occurred within a 10-foot wide band parallel to the strike of the fault. Structures and railroads built at different times during the past 100 years give a time-history of the slippage. The slippage, if any, between 1868 and 1909 is unknown. From 1909 until as late as 1949 or early 1950, there was no observed fault slippage. Approximately one-half foot of slippage occurred between about 1949 or early 1950 and about 1957, and no measurable slippage since 1957.

scholarly journals Structural characterization of fault damage zones in carbonates (Central Apennines, Italy)

2021 ◽  
Author(s):  
Miriana Chinello ◽  
Michele Fondriest ◽  
Giulio Di Toro
Keyword(s):  
Fault Zone ◽  
Hanging Wall ◽  
Damage Zone ◽  
Normal Fault ◽  
Vertical Displacement ◽  
Fault System ◽  
Normal Faults ◽  
Central Apennines ◽  
Fault Surface ◽  
Fracture Intensity

&lt;p&gt;The Italian Central Apennines are one of the most seismically active areas in the Mediterranean (e.g., L&amp;#8217;Aquila 2009, Mw 6.3 earthquake). The mainshocks and the aftershocks of these earthquake sequences propagate and often nucleate in fault zones cutting km-thick limestones and dolostones formations. An impressive feature of these faults is the presence, at their footwall, of few meters to hundreds of meters thick damage zones. However, the mechanism of formation of these damage zones and their role during (1) individual seismic ruptures (e.g., rupture arrest), (2) seismic sequences (e.g., aftershock evolution) and (3) seismic cycle (e.g., long term fault zone healing) are unknown. This limitation is also due to the lack of knowledge regarding the distribution, along strike and with depth, of damage with wall rock lithology, geometrical characteristics (fault length, inherited structures, etc.) and kinematic properties (cumulative displacement, strain rate, etc.) of the associated main faults.&lt;/p&gt;&lt;p&gt;Previous high-resolution field structural surveys were performed on the Vado di Corno Fault Zone, a segment of the ca. 20 km long Campo Imperatore normal fault system, which accommodated ~ 1500 m of vertical displacement (Fondriest et al., 2020). The damage zone was up to 400 m thick and dominated by intensely fractured (1-2 cm spaced joints) dolomitized limestones with the thickest volumes at fault oversteps and where the fault cuts through an older thrust zone. Here we describe two minor faults located in the same area (Central Apennines), but with shorter length along strike. They both strike NNW-SSE and accommodated a vertical displacement of ~300 m.&lt;/p&gt;&lt;p&gt;The Subequana Valley Fault is about 9 km long and consists of multiple segments disposed in an en-echelon array. The fault juxtaposes pelagic limestones at the footwall and quaternary deposits at the hanging wall. The damage zone is &lt; 25 m &amp;#160;thick &amp;#160;and comprises fractured (1-2 cm spaced joints) limestones beds with decreasing fracture intensity moving away from the master fault. However, the damage zone thickness increases up to &amp;#8764;100 m in proximity of subsidiary faults striking NNE-SSW. The latter could be reactivated inherited structures.&lt;/p&gt;&lt;p&gt;The Monte Capo di Serre Fault is about 8 km long and characterized by a sharp ultra-polished master fault surface which cuts locally dolomitized Jurassic platform limestones. The damage zone is up to 120 m thick and cut by 10-20 cm spaced joints, but it reaches an higher fracture intensity where is cut by subsidiary, possibly inherited, faults striking NNE-SSW.&lt;/p&gt;&lt;p&gt;Based on these preliminary observations, faults with similar displacement show comparable damage zone thicknesses. The most relevant damage zone thickness variations are related to geometrical complexities rather than changes in lithology (platform vs pelagic carbonates). &amp;#160;In particular, the largest values of damage zone thickness and fracture intensity occur at fault overstep or are associated to inherited structures. The latter, by acting as strong or weak barriers (sensu Das and Aki, 1977) during the propagation of seismic ruptures, have a key role in the formation of damage zones and the growth of normal faults.&lt;/p&gt;

Modelling the effects of normal faulting on alluvial river morphodynamics.

2021 ◽  
Author(s):  
Hessel Woolderink ◽  
Steven Weisscher ◽  
Maarten Kleinhans ◽  
Cornelis Kasse ◽  
Ronald Van Balen
Keyword(s):  
Fault Zone ◽  
Dynamic Equilibrium ◽  
Normal Fault ◽  
Vertical Displacement ◽  
Normal Faulting ◽  
Alluvial Rivers ◽  
Alluvial River ◽  
River Bed ◽  
Chute Cutoff ◽  
Meander Bends

&lt;p&gt;Normal faulting acts as a forcing on the morphodynamics of alluvial rivers by changing the topographic gradient of the river valley and channel around the fault zone. Normal faulting affects river morphodynamics either instantaneously by surface rupturing earthquakes, or gradually by continuous vertical displacement. The morphodynamic responses to normal faulting range from longitudinal bed profile adjustments to channel pattern changes. However, the effect of faulting on river morphodynamics and morphology is complex, as they also depend on numerous local, non-tectonic characteristics of flow, river bed/bank composition and vegetation cover. Moreover, river response to faulting is often transient. Such time-dependent river response is important to consider when deriving relationships between faulting and river dynamics from a morphological and sedimentological record. To enhance our understanding of river response to tectonic faulting, we used the physics-based, two-dimensional morphodynamic model Nays2D to simulate the responses of a laboratory-scale alluvial river to various faulting and offset scenarios. Our model focusses on the morphodynamic responses at the scale of multiple meander bends around a normal fault zone. Channel sinuosity increases as the downstream meander bend expands as a result of the faulting-enhanced valley gradient, after which a chute cutoff reduces channel sinuosity to a new dynamic equilibrium that is generally higher than the pre-faulting sinuosity. Relative uplift of the downstream part of the river due to a fault leads to reduced fluvial activity upstream, caused by a backwater effect. The position along a meander bend at which faulting occurs has a profound influence on channel sinuosity; fault locations that enhance flow velocities over the point bar result in a faster sinuosity increase and subsequent chute cutoff than locations that cause increased flow velocity directed towards the outer floodplain. Our study shows that inclusion of process-based reasoning in the interpretation of geomorphological and sedimentological observations of fluvial response to faulting improves our understanding of the natural processes involved and, therefore, contributes to better prediction of faulting effects on river morphodynamics.&lt;/p&gt;

Postglacial Mw 7.0–7.5 Earthquakes on the North Olympic Fault Zone, Washington

2020 ◽  
Author(s):  
Elizabeth R. Schermer ◽  
Colin B. Amos ◽  
William Cody Duckworth ◽  
Alan R. Nelson ◽  
Stephen Angster ◽  
...  
Keyword(s):  
Fault Zone ◽  
Single Event ◽  
Fault Rupture ◽  
Time Intervals ◽  
Slip Rates ◽  
Permanent Strain ◽  
Rupture Length ◽  
The North ◽  
Slip History ◽  
History Of

ABSTRACT Holocene crustal faulting in the northern Olympic Peninsula of Washington State manifests in a zone of west-northwest-striking crustal faults herein named the North Olympic fault zone, which extends for ∼80  km along strike and includes the Lake Creek–Boundary Creek fault to the east and the Sadie Creek fault and newly discovered scarps to the west. This study focuses on the Sadie Creek fault, which extends for &gt;14  km west-northwest from Lake Crescent. Airborne light detection and ranging (lidar) imagery reveals the trace of the Sadie Creek fault and offset postglacial landforms showing a history of Holocene surface-rupturing earthquakes dominated by dextral displacement along a steeply dipping fault zone. Paleoseismic trenches at two sites on the Sadie Creek fault reveal till and outwash overlain by progressively buried forest and wetland soils developed on scarp-derived colluvial wedges. Trench exposures of complex faulting with subhorizontal slickenlines indicate dextral displacement with lesser dip slip. Correlation of broadly constrained time intervals for earthquakes at the Sadie Creek sites and those to the east along the Lake Creek–Boundary Creek fault is consistent with rupture of much of the length of the North Olympic fault zone three to four times: at about 11, 7, 3, and 1 ka, with a shorter rupture at about 8.5 ka. Dated ruptures from trenches only partially coincide with coseismic landslides and megaturbidites in Lake Crescent, indicating that some earthquakes did not trigger megaturbidites, and some turbidites were unrelated to local fault rupture. Landform mapping suggests single-event dextral displacement of 4±1  m on the Sadie Creek fault. Inferred maximum rupture length and single-event slip imply earthquake magnitudes Mw 7.0–7.5. Dextral slip rates of 1.3–2.3  mm/yr and the ∼11,000  yr slip history suggest that the North Olympic fault zone is a prominent contributor to permanent strain in the northern Cascadia fore-arc.

scholarly journals Centrifuge modeling of normal faulting and underground tunnel in sandy soil deposit

2021 ◽  
Vol 44 (2) ◽  
pp. 1-13
Author(s):  
Ali Nabizadeh ◽  
Alireza Seghateh Mojtahedi
Keyword(s):  
Free Field ◽  
Soil Layer ◽  
Ground Surface ◽  
Normal Fault ◽  
Vertical Displacement ◽  
Centrifuge Modeling ◽  
Fault Rupture ◽  
Normal Faulting ◽  
Axis Parallel ◽  
Propagation Pattern

Earthquakes of large magnitudes cause fault ruptures propagation in soil layers and lead to interactions with subsurface and surface structures. The emergence of fault ruptures on or adjacent to the position of existing tunnels cause significant damage to the tunnels. The objective of this paper is to study the interaction of an embedded tunnel within a soil layer and the soil deformations imposed upon by normal faulting. A centrifuge modeling under 80-g acceleration was conducted to investigate the rupture propagation pattern for different relative tunnel positions. Compared with the free field condition, due to tunnel and normal fault rupture interactions, focused on soil relative density and tunnel rigidity in this research, found that they can dramatically modify the rupture path depending on the tunnel position relative to the fault tip. The tunnel diverts the rupture path to its sides. This study presents the normal fault-tunnel interaction with the tunnel axis parallel to the normal fault line, to examine the changes that take place in fault rupture plane locations, the vertical displacement of the ground surface with tunnel presence and the effect of tunnel rigidity and soil density on fault tunnel interaction.

Evaluation of concomitant gynecological pathology in group of patients of reproductive age with tumors and tumor formations

2020 ◽  
pp. 10-14
Author(s):  
N. V. Spiridonova ◽  
A. A. Demura ◽  
V. Yu. Schukin
Keyword(s):  
Diagnostic Errors ◽  
Ovarian Tumors ◽  
Reproductive Age ◽  
Women Of Reproductive Age ◽  
Predisposing Factor ◽  
Ovarian Tumours ◽  
Preoperative Diagnostic ◽  
Neoplastic Process ◽  
History Of ◽  
The Moment

According to modern literature, the frequency of preoperative diagnostic errors for tumour-like formations is 30.9–45.6%, for malignant ovarian tumors is 25.0–51.0%. The complexity of this situation is asymptomatic tumor in the ovaries and failure to identify a neoplastic process, which is especially important for young women, as well as ease the transition of tumors from one category to another (evolution of the tumor) and the source of the aggressive behavior of the tumor. The purpose of our study was to evaluate the history of concomitant gynecological pathology in a group of patients of reproductive age with ovarian tumors and tumoroid formations, as a predisposing factor for the development of neoplastic process in the ovaries. In our work, we collected and processed complaints and data of obstetric and gynecological anamnesis of 168 patients of reproductive age (18–40 years), operated on the basis of the Department of oncogynecology for tumors and ovarian tumours in the Samara Regional Clinical Oncology Dispensary from 2012 to 2015. We can conclude that since the prognosis of neoplastic process in the ovaries is generally good with timely detection and this disease occurs mainly in women of reproductive age, doctors need to know that when assessing the parity and the presence of gynecological pathology at the moment or in anamnesis, it is not possible to identify alarming risk factors for the development of cancer in the ovaries.

The Goal of the Moment (Summary of the Lecture Delivered by Ivan Ilyin in May 1917)

2019 ◽  
Vol 60 ◽  
pp. 424-428
Author(s):  
Alexandra I. Vakulinskaya
Keyword(s):  
The State ◽  
October Revolution ◽  
Legal Consciousness ◽  
New Order ◽  
History Of ◽  
The Moment

This publication is devoted to one of the episodes of I. A. Ilyin’s activity in the period “between two revolutions”. Before the October revolution, the young philosopher was inspired by the events of February 1917 and devoted a lot of time to speeches and publications on the possibility of building a new order in the state. The published archive text indicates that the development of Ilyin’s doctrine “on legal consciousness” falls precisely at this tragic moment in the history of Russia.

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