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Bimodal or quadrimodal? Statistical tests for the shape of fault patterns

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Bimodal or quadrimodal? Statistical tests for the shape of fault patterns. / Healy, David; Jupp, Peter.

In: Solid Earth, Vol. 9, No. 4, 22.08.2018, p. 1051-1060.

Research output: Contribution to journalArticle

Harvard

Healy, D & Jupp, P 2018, 'Bimodal or quadrimodal? Statistical tests for the shape of fault patterns', Solid Earth, vol. 9, no. 4, pp. 1051-1060. https://doi.org/10.5194/se-9-1051-2018

APA

Healy, D., & Jupp, P. (2018). Bimodal or quadrimodal? Statistical tests for the shape of fault patterns. Solid Earth, 9(4), 1051-1060. https://doi.org/10.5194/se-9-1051-2018

Vancouver

Healy D, Jupp P. Bimodal or quadrimodal? Statistical tests for the shape of fault patterns. Solid Earth. 2018 Aug 22;9(4):1051-1060. https://doi.org/10.5194/se-9-1051-2018

Author

Healy, David ; Jupp, Peter. / Bimodal or quadrimodal? Statistical tests for the shape of fault patterns. In: Solid Earth. 2018 ; Vol. 9, No. 4. pp. 1051-1060.

Bibtex - Download

@article{65566ce3b9c146eebe8ff08bec113bf9,
title = "Bimodal or quadrimodal? Statistical tests for the shape of fault patterns",
abstract = "Natural fault patterns formed in response to a single tectonic event often display significant variation in their orientation distribution. The cause of this variation is the subject of some debate: it could be {"}noise{"} on underlying conjugate (or bimodal) fault patterns or it could be intrinsic {"}signal{"} from an underlying polymodal (e.g. quadrimodal) pattern. In this contribution, we present new statistical tests to assess the probability of a fault pattern having two (bimodal, or conjugate) or four (quadrimodal) underlying modes and orthorhombic symmetry. We use the eigenvalues of the second- and fourth-rank orientation tensors, derived from the direction cosines of the poles to the fault planes, as the basis for our tests. Using a combination of the existing fabric eigenvalue (or modified Flinn) plot and our new tests, we can discriminate reliably between bimodal (conjugate) and quadrimodal fault patterns. We validate our tests using synthetic fault orientation datasets constructed from multimodal Watson distributions and then assess six natural fault datasets from outcrops and earthquake focal plane solutions. We show that five out of six of these natural datasets are probably quadrimodal and orthorhombic. The tests have been implemented in the R language and a link is given to the authors' source code.",
author = "David Healy and Peter Jupp",
note = "David Healy gratefully acknowledges receipt of NERC grant NE/N003063/1 and thanks the School of Geosciences at the University of Aberdeen for accommodating a period of research study leave, during which time this paper was written.",
year = "2018",
month = aug,
day = "22",
doi = "10.5194/se-9-1051-2018",
language = "English",
volume = "9",
pages = "1051--1060",
journal = "Solid Earth",
issn = "1869-9510",
publisher = "European Geosciences Union",
number = "4",

}

RIS (suitable for import to EndNote) - Download

TY - JOUR

T1 - Bimodal or quadrimodal? Statistical tests for the shape of fault patterns

AU - Healy, David

AU - Jupp, Peter

N1 - David Healy gratefully acknowledges receipt of NERC grant NE/N003063/1 and thanks the School of Geosciences at the University of Aberdeen for accommodating a period of research study leave, during which time this paper was written.

PY - 2018/8/22

Y1 - 2018/8/22

N2 - Natural fault patterns formed in response to a single tectonic event often display significant variation in their orientation distribution. The cause of this variation is the subject of some debate: it could be "noise" on underlying conjugate (or bimodal) fault patterns or it could be intrinsic "signal" from an underlying polymodal (e.g. quadrimodal) pattern. In this contribution, we present new statistical tests to assess the probability of a fault pattern having two (bimodal, or conjugate) or four (quadrimodal) underlying modes and orthorhombic symmetry. We use the eigenvalues of the second- and fourth-rank orientation tensors, derived from the direction cosines of the poles to the fault planes, as the basis for our tests. Using a combination of the existing fabric eigenvalue (or modified Flinn) plot and our new tests, we can discriminate reliably between bimodal (conjugate) and quadrimodal fault patterns. We validate our tests using synthetic fault orientation datasets constructed from multimodal Watson distributions and then assess six natural fault datasets from outcrops and earthquake focal plane solutions. We show that five out of six of these natural datasets are probably quadrimodal and orthorhombic. The tests have been implemented in the R language and a link is given to the authors' source code.

AB - Natural fault patterns formed in response to a single tectonic event often display significant variation in their orientation distribution. The cause of this variation is the subject of some debate: it could be "noise" on underlying conjugate (or bimodal) fault patterns or it could be intrinsic "signal" from an underlying polymodal (e.g. quadrimodal) pattern. In this contribution, we present new statistical tests to assess the probability of a fault pattern having two (bimodal, or conjugate) or four (quadrimodal) underlying modes and orthorhombic symmetry. We use the eigenvalues of the second- and fourth-rank orientation tensors, derived from the direction cosines of the poles to the fault planes, as the basis for our tests. Using a combination of the existing fabric eigenvalue (or modified Flinn) plot and our new tests, we can discriminate reliably between bimodal (conjugate) and quadrimodal fault patterns. We validate our tests using synthetic fault orientation datasets constructed from multimodal Watson distributions and then assess six natural fault datasets from outcrops and earthquake focal plane solutions. We show that five out of six of these natural datasets are probably quadrimodal and orthorhombic. The tests have been implemented in the R language and a link is given to the authors' source code.

U2 - 10.5194/se-9-1051-2018

DO - 10.5194/se-9-1051-2018

M3 - Article

VL - 9

SP - 1051

EP - 1060

JO - Solid Earth

JF - Solid Earth

SN - 1869-9510

IS - 4

ER -

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