Kinematic study of Iquique 2014 M 8.1 earthquake: Understanding the segmentation of the seismogenic zone

Jara, Jorge; Sánchez-Reyes, Hugo; Socquet, Anne; Cotton, Fabrice; Virieux, Jean; Maksymowicz, Andrei; Díaz‐Mojica, John; Walpersdorf, Andréa; Ruiz, J. A.; Cotte, Nathalie; Norabuena, E. O.

doi:10.1016/j.epsl.2018.09.025

Cited by 23 publications

(25 citation statements)

References 45 publications

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“…4 ), and the largest aftershock ruptures the boundary between the highly locked zone and an area characterized by lower locking at 20° 46′S. Particularly, the largest aftershock ruptured down dip unlock regions of the megathrust, this situation can be interpreted as a result of static CSC caused by the mainshock as it has been demonstrated by a previous study 45 .…”

Section: Discussionsupporting

confidence: 58%

Earthquake segmentation in northern Chile correlates with curved plate geometry

Shrivastava

González

Moreno

et al. 2019

Sci Rep

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We performed an integrated analysis of the coseismic slip, afterslip and aftershock activity of the 2014 Mw 8.1 Pisagua earthquake. This earthquake seems to be spatially located between two major historical earthquakes, the 1868 Mw 8.8 earthquake in southern Peru and the 1877 Mw 8.5 earthquake in northern Chile. Continuous GPS data were used to model the coseismic slip of the mainshock and the largest aftershock (Mw 7.6). The afterslip was modeled for 273 days (end of year 2014) after the largest aftershock, revealing two patches of afterslip: a southern patch between the mainshock and the largest aftershock and a patch to the north of the mainshock. Observations from the seismic network indicate that aftershocks were concentrated near the southern patch. Conversely, the northern patch contained hardly any aftershocks, indicating a dominant aseismic slip. The Pisagua earthquake occurred within a prominent, curved section of the Andean subduction zone. This section may have acted as a barrier for the largest historical earthquakes and as an isolated segment during the Pisagua earthquake.

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Section: Discussionsupporting

confidence: 58%

Earthquake segmentation in northern Chile correlates with curved plate geometry

Shrivastava

González

Moreno

et al. 2019

Sci Rep

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“…The rupture region of the Mw 8.1 Iquique earthquake had been monitored for more than 7 years before the mainshock by the Integrated Plate boundary Observatory Chile (IPOC) (GFZ and CNRS‐INSU , 2006), providing a unique opportunity to study the spatiotemporal relationships between background seismicity, geodetically derived locking, foreshock activity, and mainshock rupture. Due to the wealth of these observational data, the Iquique earthquake sequence has been extensively studied (e.g., Duputel et al, 2015; Hayes et al, 2014; Herman et al, 2015; Jara et al, 2018; Lay et al, 2014; Meng et al, 2015; Ruiz et al, 2014; Schurr et al, 2014; Soto et al, 2019; Yagi et al, 2014). It broke a central portion of the approximately 500‐km‐long segment that ruptured last in the great 1877 northern Chile megathrust event (Ruiz & Madariaga, 2018).…”

Section: Introductionmentioning

confidence: 99%

Forming a Mogi Doughnut in the Years Prior to and Immediately Before the 2014 M8.1 Iquique, Northern Chile, Earthquake

Schurr

Moreno

Tréhu

et al. 2020

Geophysical Research Letters

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Asperities are patches where the fault surfaces stick until they break in earthquakes. Locating asperities and understanding their causes in subduction zones is challenging because they are generally located offshore. We use seismicity, interseismic and coseismic slip, and the residual gravity field to map the asperity responsible for the 2014 M8.1 Iquique, Chile, earthquake. For several years prior to the mainshock, seismicity occurred exclusively downdip of the asperity. Two weeks before the mainshock, a series of foreshocks first broke the upper plate then the updip rim of the asperity. This seismicity formed a ring around the slip patch (asperity) that later ruptured in the mainshock. The asperity correlated both with high interseismic locking and a circular gravity low, suggesting that it is controlled by geologic structure. Most features of the spatiotemporal seismicity pattern can be explained by a mechanical model in which a single asperity is stressed by relative plate motion.

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“…The northern portion of the Chilean subduction, from the city of Arica (−18.5° N) to the Mejillones Peninsula (−23° N), has been spared from major earthquakes since 1877 (Comte & Pardo, 1991; Nishenko, 1991) and has long been considered a seismic gap. On 1 April 2014, the Iquique earthquake of moment magnitude 8.2 broke a section of this seismic gap with a maximum slip of about 8 m (Duputel et al, 2015; Jara et al, 2018; Lay et al, 2014; Liu et al, 2015; Meng et al, 2015; Ruiz et al, 2014; Yagi et al, 2014). This earthquake was preceded by a series of seismic clusters described by Schurr et al (2014): The very first anomalous and shallow was reported on 23 July 2013 offshore the city of Iquique and lasted for few days; the second cluster appeared in January 2014; the last cluster that happened on 16 March 2014 and started with a major upper‐plate crustal foreshock of M w 6.7 (Bedford et al, 2015) and lasted until the mainshock of 1 April.…”

Section: Introductionmentioning

confidence: 99%

Statistical Analysis of the Preparatory Phase of the M_w 8.1 Iquique Earthquake, Chile

et al. 2020

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The 2014 Iquique seismic crisis in Chile, culminating with a M w 8.1 earthquake on 1 April, highlights a complex unlocking of the Northern Chilean subduction that has been considered a seismic gap since 1877. During the year preceding this event, at least three clusters of seismic activity have been reported: in July 2013 and January and March 2014. Recent studies have proposed large-scale slab deformation as a potential trigger for the megathrust earthquake, and these clusters possibly indicate aseismic slip transients accompanying the progressive destabilization of the plate contact. However, no evidence of gradual unlocking of the interface or transient deformation has yet been found in the seismicity rate. To address this question, we develop a dense earthquake catalog covering 15 months preceding the mainshock and derived from the continuous waveform data set recorded by the Integrated Plate Boundary Observatory Chile (IPOC) and Iquique Local Network (ILN) networks. After declustering the seismicity, a space-time analysis highlights a large-scale acceleration of the seismicity along the interface accompanied by a deceleration of intermediate-depth earthquakes. We demonstrate the existence of a seismic quiescence downdip of the mainshock rupture before the July 2013 cluster. We propose that this seismic quiescence potentially highlights fluid circulation and/or aseismic motion along upper-plate crustal fault(s).

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Kinematic study of Iquique 2014 M 8.1 earthquake: Understanding the segmentation of the seismogenic zone

Cited by 23 publications

References 45 publications

Earthquake segmentation in northern Chile correlates with curved plate geometry

Earthquake segmentation in northern Chile correlates with curved plate geometry

Forming a Mogi Doughnut in the Years Prior to and Immediately Before the 2014 M8.1 Iquique, Northern Chile, Earthquake

Statistical Analysis of the Preparatory Phase of the M_w 8.1 Iquique Earthquake, Chile

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Kinematic study of Iquique 2014 M 8.1 earthquake: Understanding the segmentation of the seismogenic zone

Cited by 23 publications

References 45 publications

Earthquake segmentation in northern Chile correlates with curved plate geometry

Earthquake segmentation in northern Chile correlates with curved plate geometry

Forming a Mogi Doughnut in the Years Prior to and Immediately Before the 2014 M8.1 Iquique, Northern Chile, Earthquake

Statistical Analysis of the Preparatory Phase of the Mw 8.1 Iquique Earthquake, Chile

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Statistical Analysis of the Preparatory Phase of the M_w 8.1 Iquique Earthquake, Chile