Partitioned off-fault deformation in the 2016 Norcia earthquake captured by differential terrestrial laser scanning

Wedmore, L.N.J.; Gregory, L.C.; McCaffrey, K.J.W.; Goodall, H.; Walters, R.J.

doi:10.1029/2018gl080858

Partitioned off-fault deformation in the 2016 Norcia earthquake captured by differential terrestrial laser scanning

Wedmore, L.N.J.; Gregory, L.C.; McCaffrey, K.J.W.; Goodall, H.; Walters, R.J.

Authors

L.N.J. Wedmore

L.C. Gregory

Professor Kenneth Mccaffrey k.j.w.mccaffrey@durham.ac.uk
Professor

H. Goodall

R.J. Walters

Abstract

Field measurements of co‐seismic fault slip often differ from surface slip models derived from satellite geodesy. Quantifying these differences is challenging as many geodetic techniques inadequately image near‐fault deformation. We use an iterative closest point (ICP) algorithm to difference pre‐ and post‐earthquake terrestrial laser scanning (TLS) point clouds to reveal cm‐scale patterns of surface deformation caused by shallow fault slip in the 2016 Mw 6.6 Norcia (central Italy) earthquake. TLS offsets are constant along the fault and match average field measurements. 84% of vertical displacement occurs on a discrete fault zone, with 16% of deformation distributed across a narrow zone <4 m wide. In contrast, horizontal deformation is distributed over an 8 m wide zone with c. 50% of extension accommodated as off‐fault deformation (OFD). The cm‐scale observation of deformation shows that horizontal and vertical co‐seismic OFD is partitioned – in this case, OFD is dominated by horizontal deformation.

Citation

Wedmore, L., Gregory, L., McCaffrey, K., Goodall, H., & Walters, R. (2019). Partitioned off-fault deformation in the 2016 Norcia earthquake captured by differential terrestrial laser scanning. Geophysical Research Letters, 46(6), 3199-3205. https://doi.org/10.1029/2018gl080858

Journal Article Type	Article
Acceptance Date	Feb 21, 2019
Online Publication Date	Feb 27, 2019
Publication Date	Mar 28, 2019
Deposit Date	Feb 27, 2019
Publicly Available Date	Aug 27, 2020
Journal	Geophysical Research Letters
Print ISSN	0094-8276
Electronic ISSN	1944-8007
Publisher	Wiley
Peer Reviewed	Peer Reviewed
Volume	46
Issue	6
Pages	3199-3205
DOI	https://doi.org/10.1029/2018gl080858

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Copyright Statement
Wedmore, L.N.J., Gregory, L.C., McCaffrey, K.J.W., Goodall, H. & Walters, R.J. (2019). Partitioned off-fault deformation in the 2016 Norcia earthquake captured by differential terrestrial laser scanning. Geophysical Research Letters 46(6): 3199-3205. 10.1029/2018GL080858. To view the published open abstract, go to https://doi.org/ and enter the DOI.