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Summary of Proposal GEO1866

TitleDeformation along the coast of central Chile following the great 2010 megathrust earthquake
Investigator Ryder, Isabelle - University of Liverpool, Earth, Ocean and Ecological Sciences
Team Member
Mr Bie, Lidong - University of Liverpool, Earth, Ocean & Ecological Sciences
Summary--------------Objectives-------------- This proposal has two connected aims: (1) to measure and characterise postseismic deformation along the coast following the 2010 Mw 8.8 Maule earthquake, central Chile; and (2) to isolate and analyse the post-post-seismic deformation associated with two major shallow aftershocks of the Maule event. This latter part follows on directly from the coseismic analysis of the Pichilemu aftershocks carried out by Ryder et al. (2012). In a more pragmatic sense, this proposal will give the PI and Co-I experience working with TerraSAR-X X-band data, which neither have previously used. --------------Methods-------------- We plan to order 17 postseismic TerraSAR-X acquisitions along the Chile coastline, on two tracks. To process these data to create differential interferograms, we will use the GMTSAR software. Continuous GPS data from a comprehensive postseismic network in the rupture area onland will be used to "ground-truth" the interferograms. The interferograms will then be used to construct InSAR time series, which will be used as input into ongoing FEM-based analyses of postseismic deformation mechanisms by the PI. The deformation associated with the Pichilemu aftershocks, as opposed to the Maule earthquake itself, will be isolated by modelling a first-order response to the megathrust rupture and subtracting it from the relevant interferograms. The Pichilemu deformation will be modelled kinematically as afterslip on the two faults identified from InSAR by Ryder et al. (2012), with any residual long-wavelength Maule signature being solved for as part of the inversion. Stress-driven afterslip inversions will also be carried out by the Co-I using Barbot's Relax code. --------------Data requirements-------------- Our study will use descending StripMap data in HH mode on two tracks along the coastal part of the central Chile subduction zone. One track (incident angle 43.3) extends from San Antonio to Constitucion, and the other (incident angle 29.4) extends from Constitucion to Concepcion. The northern track has 7 scenes, while the southern track has 10 scenes. We are therefore requesting a total of 17 scenes ("scenes" here being the complete strip as displayed on the Astrium TerraSAR-X archive interactive map). --------------Deliverables-------------- 1. Interferograms and time series of postseismic deformation 2. Kinematic and dynamic afterslip models 3. Chapter in Co-I's PhD thesis on the Pichilemu results 4. Posting of results online on PI's and Co-I's websites 5. Presentation of results at international conferences 6. Two publications (one Maule, one Pichilemu) in respected refereed journals.

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