Return of the Atacama deep Slow Slip Event: The 5-year recurrence confirmed by continuous GPS

Klein, E.; Vigny, Christophe; Duputel, Zacharie; Zigone, Dimitri; Rivera, Luis; Ruiz, Sergio; Potin, Bertrand

doi:10.1016/j.pepi.2022.106970

Cited by 6 publications

(10 citation statements)

References 50 publications

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“…As previously mentioned, Radiguet et al (2016) showed that recurrent slow-slips with no mainshock have been observed on the same interface for years, before finally triggering the 2014 M w = 7.3 Papanoa earthquake. Similar recurrent slow-slip observations were associated with the triggering of the 2012 M w = 7.6 earthquake in Costa Rica (Voss et al, 2018) or the 2020 M w = 6.9 mainshock in the Atacama region in Chile (Klein et al, 2018(Klein et al, , 2021(Klein et al, , 2023, that was followed with unusually large post-seismic displacements. There are also numerous examples of slow slip events that have been associated with seismicity swarms but not followed by a large mainshock (Lohman & McGuire, 2007;Vallée et al, 2013;Nishikawa et al, 2021).…”

Section: Discussionmentioning

confidence: 56%

Evidence of an aseismic slip continuously driving the 2017 Valparaiso earthquake sequence

Moutote

Itoh

Lengliné

et al. 2023

Preprint

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Following laboratory experiments and friction theory, slow slip events and seismicity rate accelerations observed before mainshock are often interpreted as evidence of a nucleation phase. However, such precursory observations still remain scarce and are associated with different time and length scales, raising doubts about their actual preparatory nature. We study the 2017 Valparaiso Mw= 6.9 earthquake, which was preceded by aseismic slip accompanied by an intense seismicity both suspected to reflect its nucleation phase. We complement previous observations, which have focused only on precursory activity, with a continuous investigation of seismic and aseismic processes from the foreshock sequence to the post-mainshock phase. By building a high-resolution seismicity catalog and searching for anomalous seismicity rate increases compared to aftershock triggering models, we highlight an over-productive seismicity starting within the foreshock sequence and persisting several days after the mainshock. Using repeating earthquakes and high-rate GPS observations, we highlight a transient aseismic perturbation starting just before the first foreshock and extending continuously after the mainshock. The estimated slip rate is lightly impacted by large magnitude earthquakes and does not accelerate towards the mainshock. Therefore, the unusual seismic and aseismic activity observed during the 2017 Valparaiso sequence might be interpreted as the result of a slow slip event starting before the mainshock and extending beyond it. Rather than pointing to a possible nucleation phase of the 2017 Valparaiso mainshock, the identified slow slip event acts as an aseismic loading of nearby faults, increasing the seismic activity, and thus the likelihood of a large rupture.

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Section: Discussionmentioning

confidence: 56%

Evidence of an aseismic slip continuously driving the 2017 Valparaiso earthquake sequence

Moutote

Itoh

Lengliné

et al. 2023

Preprint

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“…A similar SSE was identified starting in March 2020, confined to the southern part of the 2014 SSE (Klein et al, 2023). Aseismic slip continued at least until September 2020, when the Atacama seismic sequence (see below) began to shadow the SSE signal.…”

Section: Seismic and Aseismic Signature Of The Copiapó Ridgementioning

confidence: 56%

“…GEOFON. Purple contours mark the location of aseismic slip during the 2014 SSE (Klein, Duputel, et al, 2018), the red dot marks the approximate position of the 2020 SSE (Klein et al, 2023).…”

Section: Discussionmentioning

confidence: 99%

“…Beachballs show lower-hemisphere projections of focal mechanisms for events with magnitude ≥4.8, taken from GEOFON. Purple contours mark the location of aseismic slip during the 2014 SSE (Klein, Duputel, et al, 2018), the red dot marks the approximate position of the 2020 SSE (Klein et al, 2023).…”

Section: Discussionmentioning

confidence: 99%

“…North-Central Chile is one of the few sites where transient slow-slip events have been observed independently from large megathrust earthquakes in Chile. A SSE event of ∼18 months duration with a maximum slip of about 50 cm was observed at the deepest part of the plate interface in 2014 and 2015 (Klein, Duputel, et al, 2018), and again in 2020 (Klein et al, 2023). Swarm-like seismicity sequences have been observed in 2006 and 2015 close to the town of Caldera, updip of the SSE's location (Holtkamp et al, 2011;Ojeda et al, 2023), as well as ∼50-100 km further south in 2020 (Klein et al, 2021).…”

Section: Introductionmentioning

confidence: 98%

See 2 more Smart Citations

Relation between oceanic plate structure, patterns of interplate locking and microseismicity in the 1922 Atacama Seismic Gap

González-Vidal

Moreno

Sippl

et al. 2023

Preprint

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We deployed a dense geodetic and seismological network in the Atacama seismic gap in Chile. We derive a microseismicity catalog of >30,000 events, time series from 70 GNSS stations, and apply a transdimensional Bayesian inversion to estimate interplate locking degree. We identify two highly locked regions of different sizes whose geometries appear to control seismicity patterns. Interface seismicity concentrates beneath the coastline just downdip of the highest locking. A region of lower interplate locking around 27.5ºS coincides with higher seismicity levels, a high number of repeating earthquakes and events extending further towards the trench. Having shown numerous signs of aseismic deformation (slow-slip events and earthquake swarms), this area is situated where the Copiapó Ridge is subducted. While these findings suggest that the structure of the downgoing oceanic plate prescribes patterns of interplate locking and seismicity, we note that the Taltal Ridge further north lacks a similar signature.

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Seismic and aseismic slip during the 2006 Copiapó swarm in North-Central Chile

Ojeda

Morales‐Yáñez

Wang

et al. 2023

Journal of South American Earth Sciences

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Return of the Atacama deep Slow Slip Event: The 5-year recurrence confirmed by continuous GPS

Cited by 6 publications

References 50 publications

Evidence of an aseismic slip continuously driving the 2017 Valparaiso earthquake sequence

Evidence of an aseismic slip continuously driving the 2017 Valparaiso earthquake sequence

Relation between oceanic plate structure, patterns of interplate locking and microseismicity in the 1922 Atacama Seismic Gap

Seismic and aseismic slip during the 2006 Copiapó swarm in North-Central Chile

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