EGU2020-20862
https://doi.org/10.5194/egusphere-egu2020-20862
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Build seismic cycle balance deformation with InSAR in Northen Chile

Lauriane Bayle, Romain Jolivet, Nadaya Cubas, and Laetitia Le Pourhiet
Lauriane Bayle et al.
  • Sorbonne Université, Institut des Sciences de la Terre de Paris, Dynamique et évolution des Marges et des Orogènes, France (lauriane.bayle@upmc.fr)

Lauriane Baylé (1), Romain Jolivet (2), Nadaya Cubas (1) and Laetitia Le

Pourhiet (1)

(1) Institut des Sciences de la Terre de Paris, UMR 7193, UPMC UniversitéParis 6, CNRS, Paris,

France

(2) Laboratoire de Géologie, Département de Géosciences, École Normale Supérieure, CNRS UMR 8538,

PSL ResearchUniversity, Paris, France

Recent studies have pointed out to a discrepancy between the short- and long-

term deformation of overriding plates in subduction zones. This led to debates

about when and how permanent deformation is acquired. This contradiction

has notably been observed along the Central Andes Subduction Zone, where

the coast subsides during and shortly after major earthquakes while a coastal

uplift with rates ranging between 0.1 and 0.3 mm/yr has been inferred the

last 4000 ky. For instance, during the 15th September 2015 Mw 8.3 Illapel

earthquake the geodetics (GPS and InSAR) data show a coastal subsidence

along the line-of-sight of 20 cm in InSAR.

To reconcile the seemingly contradictory observations, we here propose to

provide a seismic cycle uplift balance by constrainning inter-, co- and post-

seismic vertical velocities from InSAR time series. The study focuses on La

Serena peninsula (71.3°W, 30°S, Chile) along which the Illapel earthquake

occurred and for which long-term uplift rates have been provided by previous

geomorphological studies.

To build this seismic cycle balance, we use InSAR data (Sentinel-1) acqui-

red between the September 15, 2015 and January 19, 2019. The time series

for the ascendant orbite is calculated and the accumulated vertical displace-

ment extracted providing co- and post-seismic displacement. The co-seismic

displacement are similar to those previously obtain. To constrain the displa-

cement during the inter-seismic period, data on both sides of the peninsula

are used. In that respect, we aim determining when, during the seismic cycle,

and where, along the coast, the uplift occurs.

The deduced time series will then be confronted to numerical modelling

to provide the short- and long-term mechanics reproducing the short- and

long-term observations.

How to cite: Bayle, L., Jolivet, R., Cubas, N., and Le Pourhiet, L.: Build seismic cycle balance deformation with InSAR in Northen Chile, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-20862, https://doi.org/10.5194/egusphere-egu2020-20862, 2020

Comments on the presentation

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Presentation version 1 – uploaded on 03 May 2020
  • CC1: Comment on EGU2020-20862, Yasser Maghsoudi, 05 May 2020

    Hi,

    Thanks for your work.

    In your time-series plot, the NSBAS and the multipixel are signifcantly different from each other. What do you think as the main factors for this huge difference?

  • CC2: Comment on EGU2020-20862, Yasser Maghsoudi, 05 May 2020

    Were the interferograms corrected with the same ampospheric model in both the NSBAS and Multipixle methods?

    • CC5: Reply to CC2, Lauriane Bayle, 08 May 2020

      Yes, I construct first my interferogramms and after I want to construct time serie. So the correction for the atmospheric delay is the same.

  • CC3: Comment on EGU2020-20862, Yasser Maghsoudi, 05 May 2020

    Is the Multipixel time-series an open source package?

    • CC4: Reply to CC3, Lauriane Bayle, 08 May 2020

      You can find mptis on github and the article of Jolivet et al. 2018 Jolivet, R., & Simons, M. (2018).
      (A multipixel time series analysis
      method accounting for ground
      motion, atmospheric noise,
      and orbital errors. Geophysical
      Research Letters, 45, 1814–1824.
      https://doi.org/10.1002/2017GL076533)