scholarly journals Three Types of Flower Structures in a Divergent-Wrench Fault Zone

2017 ◽  
Vol 122 (12) ◽  
pp. 10,478-10,497 ◽  
Author(s):  
Lei Huang ◽  
Chi-yang Liu
Keyword(s):  
Fault Zone ◽  
Wrench Fault ◽  
Flower Structures

Apache Wrench Fault Zone of West Texas: ABSTRACT

AAPG Bulletin ◽  
1996 ◽  
Vol 80 ◽  
Author(s):  
G. Pat Bolden
Keyword(s):  
Fault Zone ◽  
West Texas ◽  
Wrench Fault

The Maradi Fault Zone: 3-D Imagery of a Classic Wrench Fault in Oman

AAPG Bulletin ◽  
1993 ◽  
Vol 77 ◽  
Author(s):  
NEUHAUS, DIETMAR, Petroleum Develop
Keyword(s):  
Fault Zone ◽  
Wrench Fault

Geologic hazards of an embankment dam constructed across a major, active plate boundary fault

2000 ◽  
Vol 6 (4) ◽  
pp. 353-382
Author(s):  
Azm S. Al-Homoud
Keyword(s):  
Fault Zone ◽  
Plate Boundary ◽  
Large Earthquake ◽  
Normal Faults ◽  
Jordan Valley ◽  
Embankment Dam ◽  
Ground Acceleration ◽  
Dam Foundation ◽  
The Core ◽  
Wrench Fault

Abstract The geological structures associated with the site of the 55 million m 3 Karameh embankment dam constructed in the Jordan Valley and the tectonic effects on dam foundation and reservoir margins were reviewed. The dam crosses the strike-slip fault of the Jordan Valley Rift Zone. Trace evidence of the fault indicates a displacement of 8 to 15 m over a rupture length of some 130 km, which probably took place several centuries ago. Earthquakes with Richter magnitudes as great as 7.8 have occurred along the Jordan Valley Fault. Deterministic studies by Tapponnier (1992) indicated that the dam design should incorporate the possibility of a 7.8 event, a maximum horizontal rupture displacement on the fault of 10 m and a design peak ground acceleration (PGA) of 0.74 g at the site of the dam. These values are consistent with those which would be used in the USA for a similar case. However, the dam was actually designed by a consultant and constructed for a PGA of about a quarter of this value, based on seismic hazard analysis following guidelines of the International Committee on Large Dams (ICOLD) (1989). Moreover, the dam was designed for displacements of 6 m horizontal and 2 m vertically. Liquefiable sand layers were found in the dam foundation. A PGA of 0.50 g will trigger liquefaction of the sand layers in the dam foundation which would be expected to result in a crest settlement of 4.4 m. Slope stability analysis indicated deep failure planes in the foundation zone. The excavation of loose materials from under the dam foundation has not precluded the possibility of liquefaction occurring under the expected earthquake. Field mapping of geological features during the dam foundation excavation and construction revealed that: a) the most likely location of the Jordan Valley fault is in the area where the Wadi Mallaha stream crosses the dam axis, b) zones of en echelon type open fissures have been defined in the laminates sub-parallel to the Jordan Valley Fault Zone, c) at the Wadi Mallaha stream bed a parallel zone of faulting and warping of the Lisan Formation was identified, and d) the alignment is clearly confirmed by the exposure immediately upstream of the core at Ch 1375. The main wrench fault zone crosses the embankment footprint (upstream to downstream approximately) and reaches the surface around Ch 1375. The critical safety elements of the embankment are the core, the downstream fine filter, the chimney drain and the drainage blanket. To resist large earthquake events safely, the following safety measures should be implemented: 1. A freeboard of 7.0 m instead of the 5.0 m constructed. 2. The foundation of the dam should be stabilized against liquefaction. 3. The embankment internal zoning should be designed to accommodate damage resulting from earthquake events with a magnitude of 7.8. 4. The foundation needs relief measures downstream to lower the pore pressure. This paper describes the measures taken during construction as overall defense against future fault movements through a wide plastic core, an extensive upstream blanket, a 5.0-m thick downstream chimney filter and drain zones, a 5-m freeboard and an upstream crack stopper zone which may be critical for normal faults with a lateral extension component. The geological determination of the main wrench fault alignment resulted in the addition of an extra 2-m width to each of the already wide chimney filter and drain zones. In order to reduce potential seepage, local cut-off trenches or slush grouting were used for treatment of any open fissures at the upstream edge of the external blanket and the right bank ridge. The scale and scope of this dam and inherent engineering geological hazards are unprecedented. The design is considered deficient. This paper documents serious safety issues with the dam. The constructed dam presents serious safety risks and represents a case history of a disaster waiting to happen.

Pulse-Like Rupture Induced by Three-Dimensional Fault Zone Flower Structures

2014 ◽  
Vol 172 (5) ◽  
pp. 1229-1241 ◽  
Author(s):  
Christian Pelties ◽  
Yihe Huang ◽  
Jean-Paul Ampuero
Keyword(s):  
Fault Zone ◽  
Three Dimensional ◽  
Flower Structures

Deformation character and palaeo-fluid flow across a wrench fault within a Palaeozoic subduction–accretion system: Waratah Fault Zone, southeastern Australia

1999 ◽  
Vol 21 (2) ◽  
pp. 191-214 ◽  
Author(s):  
David R Gray ◽  
Christoph Janssen ◽  
Yevgeny Vapnik
Keyword(s):  
Fluid Flow ◽  
Fault Zone ◽  
Southeastern Australia ◽  
Wrench Fault

scholarly journals Wrench-fault structures superimposed by glaciotectonic complexes, interpreted from high-resolution reflection-seismic sections and boreholes along the western bank of Esrum Sø, north-east Sjælland, Denmark

2020 ◽  
Vol 68 ◽  
pp. 171-193
Author(s):  
Line Bayer Winslow ◽  
Stig A. Schack pedersen ◽  
Lars Ole Boldreel ◽  
Egon Nørmark
Keyword(s):  
Seismic Profile ◽  
Seismic Section ◽  
Reflection Seismic ◽  
North East ◽  
Structural Framework ◽  
Scandinavian Ice Sheet ◽  
Fault Structures ◽  
Seismic Sections ◽  
Wrench Fault ◽  
Flower Structures

Wrench-fault structures below Danian limestone and Palaeogene marl, and an overlying structural framework of Quaternary glacial deposits in north-east Sjælland, Denmark, are interpreted from two vibro-seismic sections recorded to 600 msec TWT depth. The main seismic section is 6.3 km long, N–S oriented, and intersected by a 0.7 km long, E–W oriented satellite seismic section. In addition, boreholes in the vicinity of the seismic profile are used for the interpretation. The sections were acquired in 2014 along the western shoreline of the lake Esrum Sø in the Gribskov area. In the lower part of the seismic section (the interval 100–300 msec TWT), parallel-bedded geological layers occur along most of the profile apart from six locations, where six wrench-fault structures displace the upper part of the Chalk Group and lower Palaeogene marl. The northernmost of the six wrench-fault locations correlates to the eastern slope of the buried Esrum–Alnarp valley, which suggests that the valley is an inherited tectonic feature. The location of the wrench- fault structures supports the outline of faults related to the Sorgenfrei-Tornquist Zone on previous geological maps, which had almost no seismic data from the area. Above the stratigraphic level presented by the Danian limestone and lower Palaeogene marl, a composite glaciotectonic complex comprising two glaciodynamic sequences is recognized by e.g. thrust-fault structures and the lithostratigraphy of glacial successions recorded in the wells. In parts of the seismic sections, the lowermost level of the glaciotectonic complex inherited the wrench-tectonic fault structures, most significantly seen in the northern segment. The advance of the Scandinavian ice sheet caused the glaciotectonic structures displayed in the seismic section. The two sequences represent events related to the Norwegian and the Swedish glacial advances. From the interpretation of the seismic section it is found that the glaciotectonic complex conceals the wrench-tectonic flower structures.

ABSTRACT: Flower Structures and Wrench Fault Tectonics

AAPG Bulletin ◽  
2001 ◽  
Vol 85 ◽  
Author(s):  
BOLDEN, G. PAT, Bolden Exploration,
Keyword(s):  
Fault Tectonics ◽  
Wrench Fault ◽  
Flower Structures

Possible Oil and Gas Traps Related to a Wrench-Fault Zone in Hungary

AAPG Bulletin ◽  
1991 ◽  
Vol 75 ◽  
Author(s):  
KILENYI, EVA, KATALIN LORINCZ, and
Keyword(s):  
Fault Zone ◽  
Oil And Gas ◽  
Wrench Fault
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