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Journal of Structural Geology 93 (2016) iii

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Journal of Structural Geology

journal homepage: www.elsevier .com/locate/ jsg

Photograph of the month

Multiple slickenline sets formed during a single deformation event in an Oligocene ignimbrite in Santa Maria de Río, Mesa central,Mexico. More than four planes with normal slip are observed in a quite small area. The dips of normal faults vary from 82� to 48�. The rangeof the pitch angles of slickenlines is 65�-84�. These results indicate that the faults formed under a normal fault regime. The distribution offault strikes indicates that Anderson's theory cannot explain the formation of these faults in a single tectonic event. Also, the fault pattern isnot in orthorhombic symmetry. In this way, they do not obey the three-dimensional deformation model of Reches (Reches 1983, Tectono-physics 95, 111). This fault pattern could be explained by interaction of pre-existing planes (Nieto-Samaniego et al. 1997, Tectonophysics270,197), progressive rotation of planes and/or changes in applied principal stresses (e.g. Xu et al. 2010, Stress and Earthquakes, 739).14Q 0320703, N2412628. Photograph © Shunshan Xu, UNAM. Mexico.

http://dx.doi.org/10.1016/S0191-8141(16)30189-40191-8141