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Frontiers of Earth Science

Front. Earth Sci.    2018, Vol. 12 Issue (1) : 17-23
Factors that affect coseismic folds in an overburden layer
Shaogang ZENG1,2, Yongen CAI1()
1. Department of Geophysics, Peking University, Beijing 100871, China
2. Deep Water Exploration Group, Research Institute, CNOOC Nanhai East Petroleum Bureau, Guangzhou 510200, China
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Coseismic folds induced by blind thrust faults have been observed in many earthquake zones, and they have received widespread attention from geologists and geophysicists. Numerous studies have been conducted regarding fold kinematics; however, few have studied fold dynamics quantitatively. In this paper, we establish a conceptual model with a thrust fault zone and tectonic stress load to study the factors that affect coseismic folds and their formation mechanisms using the finite element method. The numerical results show that the fault dip angle is a key factor that controls folding. The greater the dip angle is, the steeper the fold slope. The second most important factor is the overburden thickness. The thicker the overburden is, the more gradual the fold. In this case, folds are difficult to identify in field surveys. Therefore, if a fold can be easily identified with the naked eye, the overburden is likely shallow. The least important factors are the mechanical parameters of the overburden. The larger the Young’s modulus of the overburden is, the smaller the displacement of the fold and the fold slope. Strong horizontal compression and vertical extension in the overburden near the fault zone are the main mechanisms that form coseismic folds.

Keywords ground deformation      coseismic fold      blind thrust fault      finite element method     
Corresponding Authors: Yongen CAI   
Just Accepted Date: 28 November 2016   Online First Date: 20 December 2016    Issue Date: 23 January 2018
 Cite this article:   
Shaogang ZENG,Yongen CAI. Factors that affect coseismic folds in an overburden layer[J]. Front. Earth Sci., 2018, 12(1): 17-23.
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Fig.1  Sketch of the numerical model and seismic overburden fold.
Fig.2  Typical numerical results. (a)?(d) show the coseismic deformation and strain fields near the upper tip of the fault: (a) horizontal displacement field; (b) vertical displacement field; (c) and (d) horizontal and vertical strain fields (positive for extension), respectively; and (e) and (f) horizontal and vertical displacements at the ground surface, respectively. The dashed line represents the model without overburden, and the solid black line represents the model with 80 m of overburden.
Fig.3  Influence of overburden thickness on folding. (a) horizontal displacements; (b) vertical displacements.
Fig.4  Influence of mechanical parameters on overburden folds. (a) and (b) show the influence of Young’s modulus. (c) and (d) show the influence of Poisson’s ratio.
Fig.5  Influence of fault dip angle. (a) horizontal displacements; (b) vertical displacements.
Fig.6  Photographs of fault-related folding at the Wufeng excavation site. (a) The west-facing fault-related fold in the paddy field. (b) A cross-section of the Wufeng excavation site. The red dashed line is the main fault slip of the 1999 Chi-Chi earthquake (Mw=7.6) that occurred in Central Taiwan (Lee et al., 2001; Yang et al., 2014).
1 Bernard S, Avouac  J P, Dominguez  S, Simoes M (2007). Kinematics of fault-related folding derived from a sandbox experiment. Journal of Geophysical Research, 112(B3): B03S12
2 Brandes C, Tanner  D C (2014). Fault-related folding: a review of kinematic models and their application. Earth Sci Rev, 138: 352–370
3 Bray J D (2001). Developing mitigation measures for the hazards associated with earthquake surface fault rupture. Seismic Fault-induced Failures: 55–80
4 Chen G H, Xu  X W, Zheng  R Z, Yu  G H, Li  F, Li C X,  Wen X Z,  He Y L,  Ye Y Q,  Chen X C,  Wang Z C (2008). Quantitative analysis of the co-seismic surface rupture of the 2008 Wenchuan earthquake, Sichuan, China along the Beichuan-Yingxiu fault. Dizhen Dizhi, 30(3): 723–738 (in Chinese)
5 Cole D A Jr, Lade P V (1984). Influence zones in alluvium over dip-slip faults. J Geotech Eng, 110(5): 599–615
6 Donald L T, Gerald  S (2001). Geodynamics (2nd ed). Cambridge: Cambridge University Press, 78
7 Galuppo C, Toscani  G, Turrini C,  Bonini  L,  Seno S (2016). Fracture patterns evolution in sandbox fault-related anticlines. Italian Journal of Geoscience, 135(1): 5–16
8 Gudmundsson A (2004). Effect of Young’s modulus on fault displacement. C R Geosci, 336(1): 85–92
9 Hardy S, Finch  E (2006). Discrete element modeling of the influence of cover strength on basement-involved fault-propagation folding. Tectonophysics, 415(1‒4): 225–238
10 Hu C B, Zhou  Y J, Cai  Y E, Wang  C Y (2009). Study of earthquake triggering in a heterogeneous crust using a new finite element model. Seismol Res Lett, 80(5): 799–807
11 Hubert-Ferrari A, Suppe  J, Gonzalez-MieresR,  Wang X (2007). Mechanisms of active folding of the landscape (southern Tian Shan, China). Journal of Geophysical Reseach, 112(B3): B03S09
12 Hughes A N, Benesh  N P, Shaw  J H (2014). Factors that control the development of fault-bend versus faultpropagation folds: insights from mechanical models based on the discrete element method (DEM). J Struct Geol, 68: 121–141
13 Ishiyama T, Sato  H, Kato N,  Nakayama T,  Iwasaki T,  Abe S (2011). Structures of active blind thrusts beneath Tokyo Metropolitan area. AGU Fall Meeting 2011, abstract T54B-02
14 Johnson K M, Johnson  A M (2002). Mechanical models of trishear-like folds. Journal of Structure Geology, 24(2): 277–287
15 Lee J C, Chen  Y G, Sieh  K, Mueller K,  Chen W S,  Chu H T,  Chan Y C,  Rubin C,  Yeats R (2001).A vertical exposure of the 1999 surface rupture of the Chelungpu Fault at WuFeng, Western Taiwan: structural and paleoseismic implications for an active thrust fault.  Bulletin of the Seismological Society of America, 91(5): 914–929
16 Lewis M M, Jackson  C A L, Gawthorpe  R L (2013). Salt-influenced normal fault growth and forced folding: the Stavanger Fault System, North Sea. J Struct Geol, 54: 156–173
17 Lin J, Stein  R (1989). Coseismic folding, earthquake recurrence, and the 1987 source mechanism at Whittier Narrows, Los Angeles Basin, California. J Geophys Res, 94(B7): 9614–9632
18 Miller R D, Xia  J (1998). Large near-surface velocity gradients on shallow seismic reflection data. Geophysics, 63(4): 1348–1356
19 Oglesby D D, Archuleta  R J, Nielsen  S B (1998). Earthquakes on dipping faults: the effects of broken symmetry. Science, 280(5366): 1055–1059
20 Papadimitriou A, Loukidis  D, Bouckovalas G,  Karamitros D (2007). Zone of excessive ground surface distortion due to dip-slip fault rupture. 4th International Conference on Earthquake Geotechnical Engineering, Paper No.1583
21 Qayyum M, Spratt  D A, Dixon  J M, Lawrence  R D (2015). Displacement transfer from fault-bend to fault-propagation fold geometry: an example from the Himalayan thrust front. J Struct Geol, 77: 260–276
22 Roering J J, Cooke  M L, Pollard  D D (1997). Why blind thrust faults do not propagate to the Earth’s surface: numerical modeling of coseismic deformation associated with thrust-related anticlines. Journal of Geophysical Reseach, 102(B6 B2): 11901–11912
23 Shaw J H, Shearer  P M (1999). An elusive blind-thrust fault beneath metropolitan Los Angeles. Science, 283(5407): 1516–1518
24 Shaw J H, Suppe  J (1996). Earthquake hazards of active blind-thrust faults under the central Los Angeles basin, California. J Geophys Res, 101(B4): 8623–8642
25 Shi C X (1994). Materials Comprehensive Dictionary. Beijing: Chemical Industry Press (in Chinese)
26 Suppe J (1983). Geometry and kinematics of fault-bend folding. Am J Sci, 283(7): 684–721
27 Suppe J, Chou  G T, Hook  S C (1992). Rates of folding and faulting determined from growth strata. Thrust Tectonics, 105–121 doi: 10.1007/978-94-011-3066-0_9
28 Turko J M, Knuepfer  P L K (1991). Late Quaternary fault segmentation from analysis of scarp morphology. Geology, 19(7): 718–721<0718:LQFSFA>2.3.CO;2
29 Walker R T, Khatib  M M, Bahroudi  A, Rodés A,  Schnabel C,  Fattahi M,  Talebian M,  Bergman E (2015). Co-seismic, geomorphic, and geologic fold growth associated with the 1978 Tabas-e-Golshan earthquake fault in eastern Iran. Geomorphology, 237: 98–118
30 Yu G, Xu   X, Klinger Y,  Diao G, Chen  G, Feng X,  Li C, Zhu  A, Yuan R,  Guo T, Sun  X, Tan X,  An Y (2010). Fault-scarp features and cascading-rupture model for the Mw 7.9 Wenchuan Earthquake, Eastern Tibetan Plateau, China. Bull Seismol Soc Am, 100(5B): 2590–2614
31 Xu X W, Wen  X Z, Han  Z J, Chen  G H, Li  C Y, Zheng  W J, Zhnag   S M, Ren  Z Q, Xu  C, Tan X B,  Wei Z Y,  Wang M M,  Ren J J,  He Z T,  Liang M J (2013). Lushan Ms7.0 earthquake: a blind reserve-fault event. Chin Sci Bull, 58(28‒29): 3437–3443
32 Yang J L, Ilic  J G, Wardlaw  T (2003). Relationships between static and dynamic moduli of elasticity for a mixture of clear and decayed eucalypt wood. Aust For, 66(3): 193–196
33 Yang Y R, Hu  J C, Lin  M L (2014). Evolution of coseismic fault-related folds induced by the Chi-Chi earthquake: a case study of the Wufeng site, Central Taiwan by using 2D distinct element modeling. J Asian Earth Sci, 79: 130–143
34 Zhou Y J, Hu  C B, Cai  Y E (2009). Influence of an inhomogeneous stress field and fault-zone thickness on the displacements and stresses induced by normal faulting. J Struct Geol, 31(5): 491–497
35 Zuluaga  L F,  Fossen  H,  Rotevatn  A (2014). Progressive evolution of deformation band populations during Laramide fault-propagation folding: Navajo Sandstone, San Rafael monocline, Utah, U.S.A. Journal of Structural Geology, 68: 66–81
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