Strain estimation from flattened parallel folds: application of the Wellman method and Mohr circle

Parallel folds exhibit a characteristic orthogonal relationship between the tangent and the corresponding isogon drawn at any point on folded surface. Modification of parallel fold to flattened parallel fold by superimposition of homogeneous strain introduces an angular shear along the tangents at different points. The angular shears in different directions, obtained by measuring angles between the tangents and the corresponding isogons, can be used for estimation of flattening strain by a variety of geometrical and numerical methods. We show that several simple geometrical techniques, such as the Wellman method and the Mohr circle method, can rapidly decipher the strain from flattened parallel folds. These methods, in contrast to most of the existing methods of strain estimation, are independent of the assumption that one of the principal strain directions parallels the axial trace on the profile plane of fold.

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A Mohr circle method for 3D strain measurement using the geometry of no finite longitudinal strain and the RXZ strain ratio

Journal of Structural Geology ◽

10.1016/j.jsg.2010.12.002 ◽

2011 ◽

Vol 33 (4) ◽

pp. 424-432 ◽

Cited By ~ 1

Author(s):

Khalil Sarkarinejad ◽

Babak Samani ◽

Ali Faghih

Keyword(s):

Strain Measurement ◽

Longitudinal Strain ◽

Circle Method ◽

Strain Ratio ◽

Mohr Circle

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Strain estimation from distorted vertebrate fossils: application of the Wellman method

Geological Magazine ◽

10.1017/s0016756806002962 ◽

2006 ◽

Vol 144 (1) ◽

pp. 211-216 ◽

Cited By ~ 4

Author(s):

JYOTI SHAH ◽

DEEPAK C. SRIVASTAVA

Keyword(s):

Vertebral Column ◽

Finite Strain ◽

Computer Graphic ◽

Principal Strain ◽

Graphic Method ◽

Two Dimensional ◽

Independent Evidence ◽

Small Segment ◽

Strain Estimation

Distortion of the vertebral column in fossils can be used for the estimation of two-dimensional finite strain by a simple geometrical technique, namely the Wellman method. We demonstrate application of the Wellman method to the distorted vertebral columns of a reptile and a stem-chordate, and use the results to restore the undistorted fossil shapes by a computer graphic method. The Wellman method is particularly efficient in situations where independent evidence for the principal strain directions, or undistorted forms, are lacking. The method is purely geometrical, easy to use, and rapid. It involves relatively low error, and works even when only a small segment of the distorted vertebral column is preserved.

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Coseismic and postseismic deformation from the 2007 Bengkulu earthquake based on GPS Data

RISET Geologi dan Pertambangan ◽

10.14203/risetgeotam2021.v31.1182 ◽

2021 ◽

Vol 31 (2) ◽

pp. 98

Author(s):

Irwan Meilano ◽

Susilo Susilo ◽

Endra Gunawan ◽

Suchi Rahmadani

Keyword(s):

Principal Strain ◽

Postseismic Deformation ◽

Gps Data ◽

Logarithmic Function ◽

Megathrust Earthquake ◽

Strain Estimation ◽

West Sumatra ◽

Extensional Strain

On September 12, 2007, a M8.5 megathrust earthquake occurred along the Sunda trench near Bengkulu, West Sumatra. GPS data in Sumatra have indicated the coseismic and postseismic deformations resulting from this earthquake. Our estimate of coseismic displacements suggests that the earthquake displaced up to ~1.8m at GPS stations located north of the epicenter. Moreover, our principal strain estimation in the region suggests that the maximum coseismic extensional strain is ~40 ppm. Our analysis of GPS data in the region suggests that the postseismic decay of the 2007 Bengkulu earthquake was 46 days, estimated using a logarithmic function.

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Ultrastructural autoradiography of L6 skeletal-muscle cells exposed to a tritiated macrolide antibiotic (LY237216) in vitro

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100123465 ◽

1992 ◽

Vol 50 (1) ◽

pp. 612-613

Author(s):

S.L. White ◽

C.B. Jensen ◽

D.D. Giera ◽

D.A. Laska ◽

M.N. Novilla ◽

...

Keyword(s):

Skeletal Muscle ◽

Quantitative Analysis ◽

Macrolide Antibiotic ◽

Circle Method ◽

Apical Surface ◽

Polycarbonate Membrane ◽

L6 Cells ◽

Low Viscosity ◽

Erythromycin A

In vitro exposure to LY237216 (9-Deoxo-11-deoxy-9,11-{imino[2-(2-methoxyethoxy)ethylidene]-oxy}-(9S)-erythromycin), a macrolide antibiotic, was found to induce cytoplasmic vacuolation in L6 skeletal muscle myoblast cultures (White, S.L., unpubl). The present study was done to determine, by autoradiographic quantitative analysis, the subcellular distribution of 3H-LY237216 in L6 cells.L6 cells (ATCC, CRL 1458) were cultured to confluency on polycarbonate membrane filters (Millipore Corp., Bedford, MA) in M-199 medium (GIBCO® Labs) with 10% fetal bovine serum. The cells were exposed from the apical surface for 1-hour to unlabelled-compound (0 μCi/ml) or 50 (μCi/ml of 3H-LY237216 at a compound concentration of 0.25 mg/ml. Following a rapid rinse in compound-free growth medium, the cells were slam-frozen against a liquid nitrogen cooled, polished copper block in a CF-100 cryofixation unit (LifeCell Corp., The Woodlands, TX). Specimens were dried in the MDD-C Molecular Distillation Drier (LifeCell Corp.), vapor osmicated and embedded in Spurrs low viscosity resin. Ultrathin sections collected on formvar coated stainless steel grids were counter-stained, then individually mounted on corks. A monolayer of Ilford L4 nuclear emulsion (Polysciences, Inc., Warrington, PA) was placed on the sections, utilizing a modified “loop method”. The emulsions were exposed for 7-weeks in a light-tight box at 4°C. Autoradiographs were developed in Microdol-X developer and examined on a Philips EM410LS transmission electron microscope. Quantitative analysis of compound localization employed the point and circle approach of Williams; incorporating the probability circle method of Salpeter and McHenry.

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