WP 2.3 Long-term deformation in the South Iceland seismic zone inferred by joint interpretation of GPS, InSAR and borehole strain data

Start date or starting event:

M0

Lead contractor:

NVI

Participants:                                                   NVI, CNRS-UMR 5562

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Objectives:

1.        To evaluate the long-term three-dimensional deformation field of the Earth in the South Iceland seismic zone prior to 2000 earthquakes, and post-seismic deformation after the earthquakes.

2.        To derive a strain rate map for the South Iceland seismic zone prior to the earthquakes.

3.        To search for long-term precursor in geodetic signals.

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Inputs:

1.        Existing CGPS network.

2.        Network GPS measurements.

3.        Data from a network of borehole strainmeters.

4.        Raw SAR data from ERS, ENVISAT and/or ALOS satellite missions for which we are privileged investigators with access to reduced-price data.

5.        Data from electronic distance measurements.

6.        Software for analyzing above data.

Methodology / work description:

Geodetic observations perform several roles in the quest for earthquake prediction, including the possibility of recording a precursory signal.  Geodetic data is also essential input to models of stress transfer.

An extensive geodetic data covering deformation in the SISZ already exists.  We will combine all these different data into one unified model for the three-dimensional deformation field in the South Iceland seismic zone prior to the 2000 earthquakes.  The data includes 10 continuously recording GPS stations, results from network GPS measurements, a series of InSAR interferograms, going back to 1992, results from a network of borehole strainmeters, and electronic distance measurements.

Knowing the displacement field, a strain rate map will be inferred for the seismic zone, that will reveal the spatial distribution of strain in the area.  Pre-seismic strain is expected to be highest in the central area of the South Iceland seismic zone, but exact shape of the strain field will be important to understand the earthquakes, and predict where further earthquakes may occur.

The data will be explored for potential long-term precursors that might have occurred over years prior to the earthquake sequence, including changes in displacement rates or strain measured by the network of borehole strainmeters.

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Deliverables including cost of deliverable as percentage of total cost of the proposed project:

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Milestones: Delivery of the above items at the date indicated.