Study on Small Diameter and Low Steel Grade Pipeline Crossing Strike-Slip and Thrust Fault

2021 ◽  
Vol 43 (03) ◽  
pp. 167-175
Author(s):  
晨 许
Keyword(s):  
Small Diameter ◽  
Thrust Fault ◽  
Strike Slip ◽  
Steel Grade ◽  
Pipeline Crossing

Time evolution of stress under an artificial lake and its implication for induced seismicity

1978 ◽  
Vol 15 (9) ◽  
pp. 1526-1534 ◽  
Author(s):  
R. J. Withers ◽  
E. Nyland
Keyword(s):  
Induced Seismicity ◽  
Time History ◽  
Normal Fault ◽  
Thrust Fault ◽  
Strike Slip ◽  
Loading History ◽  
Failure Envelope ◽  
Artificial Lake ◽  
Coulomb Failure ◽  
History Of

The time history of stress beneath a realistic artificial lake with a realistic loading history on a permeable lithosphere can be calculated by solving the consolidation equations for a uniform permeable medium. The evolution of stress conditions towards or away from a Mohr–Coulomb failure envelope illustrates that highest risk of induced seismicity exists at initial loading and in some cases after a down-draw of the lake. The calculated histories depend crucially on hydrologic and geologic conditions which are very poorly known at many artificial lakes. If the formation strengths are constant in the area of the lake, consolidation theory indicates that failure is most likely under the lake in strike-slip or normal fault regimes. If failure occurs due to loading on a thrust fault regime it will occur at an offset from the lake.

Effect of block rotation on the pitch of slickenlines

2011 ◽  
Vol 3 (1) ◽  
Author(s):  
Shunshan Xu ◽  
Ángel Nieto-Samaniego ◽  
Susana Alaniz-Álvarez ◽  
Luis Velasquillo-Martínez
Keyword(s):  
Stress Tensor ◽  
Normal Fault ◽  
Thrust Fault ◽  
Strike Slip ◽  
Far Field ◽  
Block Rotation ◽  
Calculated Stress ◽  
Stress States ◽  
Far Field Stress ◽  
Rotation Stress

AbstractRotation of faults or pre-existing weakness planes produce two effects on the slickenlines of fault planes. First, the rotation leads to changes in the pitch of slickenlines. As a result, the aspect of the pre-existing fault may change. For example, after rotation, a normal fault may show features of an oblique fault, a strike-slip fault, or a thrust fault. Second, due to rotation, stress states on the fault planes are different from those before the rotation. As a consequence some previous planes may be reactivated. For an isolated plane, the reactivation due to rotation can produce new sets of slickenlines. With block rotation, superimposed slickenlines can be generated in the same tectonic phase. Thus, it is not appropriate to use fault-slip data from slickenlines to analyze the stress tensor in a region where there is evidence of block rotation. As an example, we present the data of slickenlines from core samples in the Tunich area of the Gulf of Mexico. The results wrongly indicate that the calculated stress tensor deviates from the far-field stress tensor.

Hydrocarbon Play of Ordovician Carbonate Dominated by Faulting and Karstification—A Case Study of Yingshan Formation on Northern Slope of Tazhong Area in Tarim Basin, NW China

2011 ◽  
Vol 29 (6) ◽  
pp. 743-758 ◽  
Author(s):  
Xiuxiang Lü ◽  
Xiang Wang ◽  
Jianfa Han ◽  
Weiwei Jiao ◽  
Hongfeng Yu ◽  
...  
Keyword(s):  
Tarim Basin ◽  
Thrust Fault ◽  
Strike Slip ◽  
Strike Slip Fault ◽  
Weathering Crust ◽  
Northern Slope ◽  
Nw China ◽  
Yingshan Formation ◽  
Lower Ordovician ◽  
Tazhong Area

Large-scale weathering crust karsted carbonate reservoir beds were developed in the Lower Ordovician Yingshan Formation on the northern slope of the Tazhong area in the Tarim Basin, NW China. The research on weathering crust karsted reservoir beds and faulting showed strongly heterogeneous karsted reservoir beds characterized by horizontal contiguous distribution and vertical superimposition, with fracture-hole as the main reservoir space. High quality reservoir beds were developed in the vertical seepage zone and horizontal phreatic zone, 0–200 meters below the unconformity. Reservoir bed quality of karsted carbonate rock was greatly improved by faulting, which increased the depth and size of karstification. A strike-slip fault developed over a long period in the NE direction and a thrust fault in the NW direction crossed each other, and caused distinct segmentation of the Tazhong No.1 Fault and dissection of the Yingshan Formation into multiple structural units. The strike-slip fault was the significant hydrocarbon migration pathway. Multiple hydrocarbon charging points were formed by the thrust fault and strike-slip fault, as the important fill-in of late-stage gas accumulation. Under the dual control of faulting and karstification, accumulation of hydrocarbons in the Lower Ordovician Yingshan Formation showed distinct segment-wise and block-wise features. Oil distribution is “high in the west and interior, low in the east and exterior”, while gas distribution is the opposite. The hydrocarbon play extends within 0.8–4.5 kilometers from the strike-slip fault and appeared layered vertically at 10–220 meters below the unconformity.

The Darfield (Canterbury) earthquake

2010 ◽  
Vol 43 (4) ◽  
pp. 228-235 ◽  
Author(s):  
J. Beavan ◽  
S. Samsonov ◽  
M. Motagh ◽  
L. Wallace ◽  
S. Ellis ◽  
...  
Keyword(s):  
Ground Deformation ◽  
Thrust Fault ◽  
Source Model ◽  
Strike Slip ◽  
High Quality ◽  
Preliminary Results

High quality GPS and differential InSAR data have been collected for determining the ground deformation associated with the September 2010 Darfield (Canterbury) earthquake. We report preliminary results from a subset of these data and derive a preliminary source model for the earthquake. While the majority of moment release in the earthquake occurred on the strike-slip Greendale Fault a number of other fault segments were active during the earthquake including a steeply southeast-dipping thrust fault coincident with the earthquake hypocentre.

Acadian deformation in the shallow crust: an example from the Siluro-Devonian Arisaig Group, Avalon terrane, mainland Nova Scotia

2006 ◽  
Vol 43 (1) ◽  
pp. 71-81 ◽  
Author(s):  
James A Braid ◽  
J Brendan Murphy
Keyword(s):  
Nova Scotia ◽  
Shear Zones ◽  
Thrust Fault ◽  
Structural Features ◽  
Strike Slip ◽  
Normal Faults ◽  
Progressive Deformation ◽  
Acadian Orogeny ◽  
Shallow Crust ◽  
Dextral Strike Slip

The Silurian – Early Devonian Arisaig Group of the Avalon terrane in northern mainland Nova Scotia consists mainly of thinly bedded sandstones, siltstones, and shales deposited in a near shore environment. These strata were deformed in the middle Devonian to form regional northeast- to NNE-trending folds and record deformation processes in the shallow crust during the Acadian orogeny, one of the most regionally extensive orogenic events in the Canadian Appalachians. Structural features in the Arisaig Group are consistent with fold propagation associated with thrust fault geometry and coeval local extension recorded by a set of conjugate normal faults. Many outcrop-scale folds have sheared limbs and show evidence of a complex progressive deformation. Folding was predominantly accomplished by bulk rotation and flattening above thrust fault tips. Early structures (D1–D2) produced regional cylindrical folds, whereas later (D3a, D3b, D3c) structures produced conical folds. D1–D3 fold orientations show high variability, but are consistent with progressive deformation related to reactivation and coeval dextral strike-slip movement along the Hollow Fault. The style of deformation is compatible with models in which strain is partitioned into preexisting shear zones in the basement, with folds in the overlying Arisaig Group initiated above the tips of upward-propagating thrusts as second-order structures related to movement along those shear zones. Taken together, these data indicate that fold mechanisms and geometry in the shallow crust during the Acadian orogeny in mainland Nova Scotia may be related to dextral strike-slip along major faults in the basement and co-genetic upward-propagating thrusts that rotated and flattened overlying strata.

scholarly journals Geology and characteristics of Pb-Zn-Cu-Ag skarn deposit at Ruwai, Lamandau Regency, Central Kalimantan

2015 ◽  
Vol 3 (1) ◽  
Author(s):  
Arifudin Idrus ◽  
Lucas Donny Setijadji ◽  
Fenny Tamba ◽  
Ferian Anggara
Keyword(s):  
Low Temperature ◽  
Hydrothermal Fluid ◽  
Meteoric Water ◽  
Volcanic Rocks ◽  
Thrust Fault ◽  
Strike Slip ◽  
Skarn Deposit ◽  
Central Kalimantan ◽  
Low Salinity ◽  
Ore Mineralization

This study is dealing with geology and characteristics of mineralogy, geochemistry and physicochemical conditions of hydrothermal fluid responsible for the formation of skarn Pb-Zn-Cu-Ag deposit at Ruwai, Lamandau Regency, Central Kalimantan. The formation of Ruwai skarn is genetically associated with calcareous rocks consisting of limestone and siltstone (derived from marl?) and controlled by NNE-SSW-trending strike slip faults and localized along N 70° E-trending thrust fault, which also acts as contact zone between sedimentary and volcanic rocks in the area. Ruwai skarn is mineralogically characterized by prograde alteration (garnet and clino-pyroxene) and retrograde alteration (epidote, chlorite, calcite and sericite). Ore mineralization is characterized by sphalerite, galena, chalcopyrite and Ag-sulphides (particularly acanthite and argentite), which formed at early retrograde stage. Geochemically, SiO2 is enriched and CaO is depleted in limestone, consistent with silicic alteration (quartz and calc-silicate) and decarbonatization of the wallrock. The measured reserves of the deposit are 2,297,185 tonnes at average grades of 14.98 % Zn, 6.44 % Pb, 2.49 % Cu and 370.87 g/t Ag. Ruwai skarn orebody originated at moderate temperature of 250-266 °C and low salinity of 0.3-0.5 wt.% NaCl eq. The late retrograde stage formed at low temperature of 190-220 °C and low salinity of ~0.35 wt.% NaCl eq., which was influenced by meteoric water incursion at the late stage of the Ruwai Pb-Zn-Cu-Ag skarn formation. Keywords: Geology, skarn, mineralogy, geochemistry, Ruwai, Central Kalimantan

scholarly journals STUDI AWAL POLA STRUKTUR BUSUR MUKA ACEH, SUMATRA BAGIAN UTARA (INDONESIA): Penafsiran dan Analisis Peta Batimetri

2016 ◽  
Vol 8 (3) ◽  
pp. 105
Author(s):  
Haryadi Permana ◽  
L. Handayani
Keyword(s):  
Subduction Zone ◽  
Deformation Zone ◽  
Thrust Fault ◽  
Middle Part ◽  
Strike Slip ◽  
Strike Slip Fault ◽  
Zone Structure ◽  
Structural Pattern ◽  
Active Deformation ◽  
Plate Subduction

Analisis morfostruktur daerah penelitian menunjukan tiga unit struktur geologi yang berbeda, antara lain zona penunjaman, zona deformasi aktif dan busur muka termasuk didalamnya tinggian busur muka dan cekungan busur muka. Struktur geologi zona penunjaman lempeng teramati sepanjang Palung Sunda paralel dengan zona deformasi aktif. Struktur geologi pada Tinggian Busur Muka membentuk sistim prisma akresi yang disusun oleh sesar anjak, sesar geser, perlipatan dan perlipatan naik. Pola kelurusan struktur umumnya berarah berarah utara baratlaut-selatan tenggara di sebelah utara lintang 5°U, arah baratlaut-tenggara pada posisi 3°-5°U, kelurusan kemudian berbelok hampir barat-timur di sekitar 2°-3°U. Perubahan arah pola kelurusan struktur tersebut ditafsirkan sebagai jawaban terhadap naiknya tingkat kemiringan penunjaman lempeng dari daerah Simeulue ke arah Lintang 5°U -7°U atau secara umum dari selatan Sumatra ke arah utara Sumatra. Di bagian tengah daerah telitian berkembang kelurusan patahan berarah utara-selatan yang memotong kelurusan berarah baratlaut-tenggara. Kelurusan tersebut ditafsirkan sebagai patahan geser dekstral dan kemungkinan masih aktif. Kata Kunci: Analisis morfostruktur, zona penunjaman, zona deformasi aktif, busur muka, kelurusan, sesar anjak, sesar geser, perlipatan, perlipatan naik, kemiringan penunjaman lempeng Morphostructure analyses of study area demonstrate three different units of geological structures: subduction zone, active deformation zone and fore-arc region, which include Fore Arc High and Fore Arc Basin. The plate subduction zone observes along Sunda Trench parallel with active deformation zone. Structure geology in Fore Arc High builds an accretionary prism system. It was composed by thrust fault, strike slip fault, folding and thrust fold. General trend of structural pattern is NNE-SSE at the north of 5°N, NW-SE direction at around 3°-5°N and changed in direction relative to E-W at about 2°-3°N. This direction variation of structural pattern trend was interpreted as a response to increase of obliquity degree of subducted plate from Simeulue area to 5° -7°N, or in general, from southern of Sumatra to north of Sumatra. NS trend lineament has developed in the middle part of study area that also sliced the NW-SE main structural direction. These structural lineaments interpreted as dextral strike slip fault and it is possibly still active. Keywords: morphostructure analyses, subduction zone, active deformation zone, fore-arc lineament, thrust fault, strike slip, folding, thrust fold, plat, plate subduction obliquity

scholarly journals Characterization of Near-Source Ground Motions with Earthquake Simulations

2001 ◽  
Vol 17 (2) ◽  
pp. 177-207 ◽  
Author(s):  
Brad T. Aagaard ◽  
John F. Hall ◽  
Thomas H. Heaton
Keyword(s):  
Ground Motions ◽  
Source Parameters ◽  
Slip Rate ◽  
Forward Direction ◽  
Thrust Fault ◽  
Sensitivity Study ◽  
Strike Slip ◽  
Earthquake Source Parameters ◽  
Moderate Sensitivity ◽  
Earthquake Simulations

We examine the characteristics of long-period near-source ground motions by conducting a sensitivity study with variations in six earthquake source parameters for both a strike-slip fault ( M 7.0-7.1) and a thrust fault ( M 6.6-7.0). The directivity of the ruptures creates large displacement and velocity pulses in the forward direction. The dynamic displacements close to the fault are comparable to the average slip. The ground motions exhibit the greatest sensitivity to the fault depth with moderate sensitivity to the rupture speed, peak slip rate, and average slip. For strike-slip faults and thrust faults with surface rupture, the maximum ground displacements and velocities occur in the region where the near-source factor from the 1997 Uniform Building Code is the largest. However, for a buried thrust fault the peak ground motions can occur up-dip from this region.

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