Splay fault slip during the Mw 8.8 2010 Maule Chile earthquake: COMMENT

Allmendinger, Richard W.; González, Gabriel; Cembrano, José; Aron, Felipe; Yáñez, Gonzalo

doi:10.1130/g34326c.1

Cited by 4 publications

(7 citation statements)

References 9 publications

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“…To link structural observations and estimate the millennial‐scale slip rate of the SMFS, we used models based on dislocation theory in an elastic half‐space [ Okada , ]. First, we defined two contrasting structural setups considering the two hypotheses on the kinematics of the SMFS [ Allmendinger et al , ; Melnick et al , ]: (1) deep‐reaching reverse faults (>8 km) and shallow normal faults (<2 km) and (2) shallow and deep‐reaching normal faults (Figure ). The first setup includes deep reverse faults inferred from seismic reflection profiles in the AB and a cluster of seismicity [ Melnick et al , , ] as well as normal faults mapped in coal mines at Coronel [ Wenzel et al , ], exposed at SMI [ Melnick et al , , ], and inferred from displaced onshore marine terraces [ Jara‐Muñoz et al , ].…”

Section: Estimating Fault‐slip Rates Using Dislocation Modelsmentioning

confidence: 99%

“…Although deep-reaching extensional splay faults have not been yet described in the Arauco Bay area, Aron et al [2013] proposed that long-term kinematics in the entire Maule segment is dominated by extensional structures that slip during megathrust Journal of Geophysical Research: Solid Earth , including the Pichilemu fault that generated M6.7 and M6.9 earthquakes 11 days after the Maule main shock [Farías et al, 2011;Ryder et al, 2012]. Allmendinger et al [2013] questioned the interpretation of reverse slip along the SMFS during the 2010 event and based on the model of Aron et al [2013] propose normal slip along the SMFS. In an attempt to test the hypothesis of Aron et al [2013] for the long-term control of topography by repeated extensional faulting during megathrust earthquakes, we present a second model setup that includes exclusively normal faults.…”

Section: Structural Model Setupsmentioning

confidence: 99%

“…For example, the 2010 Maule earthquake was followed by instantaneous reactivation along the Santa María fault and followed by motion along the Pichilemu fault 11 days after and a year later along the Mocha fault [Farías et al, 2011;Melnick et al, 2012b;Ryder et al, 2012;Hicks and Rietbrock, 2015]. All of them are trenchward dipping structures, but of apparently different kinematics during coseismic reactivation as well as integrated at millennial timescales [e.g., Farías et al, 2011;Lange et al, 2012;Melnick et al, 2012b;Allmendinger et al, 2013;Aron et al, 2013;Melnick et al, 2013]. Studying the relation between the motion of such structures during great megathrust earthquakes may contribute to seismic hazard assessments and to our understanding of the buildup of topography and basin development processes in subduction zones.…”

Section: Introductionmentioning

confidence: 99%

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Quantifying offshore fore‐arc deformation and splay‐fault slip using drowned Pleistocene shorelines, Arauco Bay, Chile

et al. 2017

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Most of the deformation associated with the seismic cycle in subduction zones occurs offshore and has been therefore difficult to quantify with direct observations at millennial timescales. Here we study millennial deformation associated with an active splay‐fault system in the Arauco Bay area off south central Chile. We describe hitherto unrecognized drowned shorelines using high‐resolution multibeam bathymetry, geomorphic, sedimentologic, and paleontologic observations and quantify uplift rates using a Landscape Evolution Model. Along a margin‐normal profile, uplift rates are 1.3 m/ka near the edge of the continental shelf, 1.5 m/ka at the emerged Santa María Island, −0.1 m/ka at the center of the Arauco Bay, and 0.3 m/ka in the mainland. The bathymetry images a complex pattern of folds and faults representing the surface expression of the crustal‐scale Santa María splay‐fault system. We modeled surface deformation using two different structural scenarios: deep‐reaching normal faults and deep‐reaching reverse faults with shallow extensional structures. Our preferred model comprises a blind reverse fault extending from 3 km depth down to the plate interface at 16 km that slips at a rate between 3.0 and 3.7 m/ka. If all the splay‐fault slip occurs during every great megathrust earthquake, with a recurrence of ~150–200 years, the fault would slip ~0.5 m per event, equivalent to a magnitude ~6.4 earthquake. However, if the splay‐fault slips only with a megathrust earthquake every ~1000 years, the fault would slip ~3.7 m per event, equivalent to a magnitude ~7.5 earthquake.

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Section: Estimating Fault‐slip Rates Using Dislocation Modelsmentioning

confidence: 99%

Section: Structural Model Setupsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Quantifying offshore fore‐arc deformation and splay‐fault slip using drowned Pleistocene shorelines, Arauco Bay, Chile

et al. 2017

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“…However, crustal faults can also generate significant earthquakes or being activated or reactivated during significant subduction earthquakes. The 2010 Maule earthquake activated two crustal faults: the Pichilemu fault of normal mechanism [19][20][21], the normal Santa Maria fault [22,23], and the Tirúa-Mocha fault of thrust mechanism [5]. In this paper, we assess the seismic potential of such faults.…”

Section: Introductionmentioning

confidence: 99%

Crustal Faults Reactivated during 2010 Mw = 8.8 Maule Earthquake in South Chile

Quezada¹,

Belmonte²

2023

Natural Hazards - New Insights

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On February 27th 2010 occurred the Mw = 8.8 Maule subduction earthquake, filling a seismic gap of south Chile. The uplift trend is mostly typical for subduction earthquakes with decreasing uplift trend from trench to arc in Andes Cordillera. However local perturbations occurred due to the reactivations of crustal faults occurred such as Pichilemu fault (normal), Santa María fault (normal) and Tirua-Mocha fault (reverse). Different kind of faults and seismic behavior evidence complex stress distribution at the overriding South American Plate. In this paper, the activity and seismicity linked of some crustal faults at Maule earthquake rupture área are considered, and the related seismic potential that can increase the seismic hazard. Some questions are the bigger magnitude that can generate these faults and if their activity is related to the interseismic or coseismic phases of the subduction seismic cycle.

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“…We thank Allmendinger et al (2013) for their Comment and appreciate this opportunity to further discuss two main lines of arguments supporting reverse fault slip along the Santa María Fault Zone (SMFZ) during the 2010 Maule (Chile) earthquake: the spatial relation between megathrust slip and the SMFZ, and the relationship between coseismic and longer-term deformation patterns.…”

mentioning

confidence: 99%