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Partitioned Off‐Fault Deformation in the 2016 Norcia Earthquake Captured by Differential Terrestrial Laser Scanning
Author(s) -
Wedmore L. N. J.,
Gregory L. C.,
McCaffrey K. J. W.,
Goodall H.,
Walters R. J.
Publication year - 2019
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2018gl080858
Subject(s) - geology , geodetic datum , geodesy , slip (aerodynamics) , deformation (meteorology) , seismology , fault (geology) , vertical displacement , geometry , geomorphology , oceanography , physics , thermodynamics , mathematics
Field measurements of coseismic 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 algorithm to difference preearthquake and postearthquake terrestrial laser scanning point clouds to reveal centimeter‐scale patterns of surface deformation caused by shallow fault slip in the 2016 M w 6.6 Norcia (Central Italy) earthquake. Terrestrial laser scanning offsets are constant along the fault and match average field measurements. Eighty‐four percent 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 approximately 50% of extension accommodated as off‐fault deformation (OFD). The centimeter‐scale observation of deformation shows that horizontal and vertical coseismic OFD is partitioned—in this case, OFD is dominated by horizontal deformation.