Vertical deformation through a complete seismic cycle at Isla Santa María, Chile

Wesson, Robert L.; Melnick, Daniel; Cisternas, Marco; Moreno, M.; Ely, Lisa L.

doi:10.1038/ngeo2468

Cited by 54 publications

(74 citation statements)

References 26 publications

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“…Observation both in nature (e.g. Wesson et al, 2015) and in experiments using seismotectonic scale models (e.g. Rosenau and Oncken, 2010) corroborates this new view on elastoplastic seismic-cycle deformation.…”

Section: Seismic-cycle Deformationsupporting

confidence: 57%

Analogue earthquakes and seismic cycles: experimental modelling across timescales

2017

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Abstract. Earth deformation is a multi-scale process ranging from seconds (seismic deformation) to millions of years (tectonic deformation). Bridging short-and long-term deformation and developing seismotectonic models has been a challenge in experimental tectonics for more than a century. Since the formulation of Reid's elastic rebound theory 100 years ago, laboratory mechanical models combining frictional and elastic elements have been used to study the dynamics of earthquakes. In the last decade, with the advent of high-resolution monitoring techniques and new rock analogue materials, laboratory earthquake experiments have evolved from simple spring-slider models to scaled analogue models. This evolution was accomplished by advances in seismology and geodesy along with relatively frequent occurrences of large earthquakes in the past decade. This coincidence has significantly increased the quality and quantity of relevant observations in nature and triggered a new understanding of earthquake dynamics. We review here the developments in analogue earthquake modelling with a focus on those seismotectonic scale models that are directly comparable to observational data on short to long timescales. We lay out the basics of analogue modelling, namely scaling, materials and monitoring, as applied in seismotectonic modelling. An overview of applications highlights the contributions of analogue earthquake models in bridging timescales of observations including earthquake statistics, rupture dynamics, ground motion, and seismic-cycle deformation up to seismotectonic evolution.

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Section: Seismic-cycle Deformationsupporting

confidence: 57%

Analogue earthquakes and seismic cycles: experimental modelling across timescales

2017

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“…Viscoelastic mantle relaxation and afterslip were used to explain the fast rates of post-seismic subsidence documented by GPS following the 2004 Sumatra 38 and 2010 Maule 19 earthquakes at islands in a similar near-trench position to Guafo. Our viscoelastic model predicts similar fast subsidence rates, which decay rapidly in the first post-earthquake decade (Supplementary Fig.…”

Section: Discussionmentioning

confidence: 99%

Back to full interseismic plate locking decades after the giant 1960 Chile earthquake

Melnick

Moreno

et al. 2018

Nat Commun

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Great megathrust earthquakes arise from the sudden release of energy accumulated during centuries of interseismic plate convergence. The moment deficit (energy available for future earthquakes) is commonly inferred by integrating the rate of interseismic plate locking over the time since the previous great earthquake. But accurate integration requires knowledge of how interseismic plate locking changes decades after earthquakes, measurements not available for most great earthquakes. Here we reconstruct the post-earthquake history of plate locking at Guafo Island, above the seismogenic zone of the giant 1960 (Mw = 9.5) Chile earthquake, through forward modeling of land-level changes inferred from aerial imagery (since 1974) and measured by GPS (since 1994). We find that interseismic locking increased to ~70% in the decade following the 1960 earthquake and then gradually to 100% by 2005. Our findings illustrate the transient evolution of plate locking in Chile, and suggest a similarly complex evolution elsewhere, with implications for the time- and magnitude-dependent probability of future events.

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“…Due to their distinct vertical zonation, some of these organisms have been used to measure coastal vertical displacements during great earthquakes [17,20,34,35]. Fitzroy and Darwin [36] pioneered the use of intertidal rocky shore invertebrates to estimate coseismic land-level changes caused by the great 1835 (M>8.5) earthquake in south-central Chile [37]. …”

Section: Introductionmentioning

confidence: 99%

Calibrating coseismic coastal land-level changes during the 2014 Iquique (Mw=8.2) earthquake (northern Chile) with leveling, GPS and intertidal biota

et al. 2017

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The April 1st 2014 Iquique earthquake (MW 8.1) occurred along the northern Chile margin where the Nazca plate is subducted below the South American continent. The last great megathrust earthquake here, in 1877 of Mw ~8.8 opened a seismic gap, which was only partly closed by the 2014 earthquake. Prior to the earthquake in 2013, and shortly after it we compared data from leveled benchmarks, deployed campaign GPS instruments, continuous GPS stations and estimated sea levels using the upper vertical level of rocky shore benthic organisms including algae, barnacles, and mussels. Land-level changes estimated from mean elevations of benchmarks indicate subsidence along a ~100-km stretch of coast, ranging from 3 to 9 cm at Corazones (18°30’S) to between 30 and 50 cm at Pisagua (19°30’S). About 15 cm of uplift was measured along the southern part of the rupture at Chanabaya (20°50’S). Land-level changes obtained from benchmarks and campaign GPS were similar at most sites (mean difference 3.7±3.2 cm). Higher differences however, were found between benchmarks and continuous GPS (mean difference 8.5±3.6 cm), possibly because sites were not collocated and separated by several kilometers. Subsidence estimated from the upper limits of intertidal fauna at Pisagua ranged between 40 to 60 cm, in general agreement with benchmarks and GPS. At Chanavaya, the magnitude and sense of displacement of the upper marine limit was variable across species, possibly due to species—dependent differences in ecology. Among the studied species, measurements on lithothamnioid calcareous algae most closely matched those made with benchmarks and GPS. When properly calibrated, rocky shore benthic species may be used to accurately measure land-level changes along coasts affected by subduction earthquakes. Our calibration of those methods will improve their accuracy when applied to coasts lacking pre-earthquake data and in estimating deformation during pre–instrumental earthquakes.

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Vertical deformation through a complete seismic cycle at Isla Santa María, Chile

Cited by 54 publications

References 26 publications

Analogue earthquakes and seismic cycles: experimental modelling across timescales

Analogue earthquakes and seismic cycles: experimental modelling across timescales

Back to full interseismic plate locking decades after the giant 1960 Chile earthquake

Calibrating coseismic coastal land-level changes during the 2014 Iquique (Mw=8.2) earthquake (northern Chile) with leveling, GPS and intertidal biota

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