Ground motion in the Vale of Pickering

BGS is monitoring surface ground motion (subsidence, uplift or stability) in the Vale of Pickering using line of slight (LOS) interferometric synthetic aperture radar (InSAR). This is an ideal technique for ground motion monitoring because:

  1. archive radar data (acquired by satellites since 1992) are available and can be used to ascertain a baseline of motion or lack of motion prior to any gas exploration/production

  2. the analysis produces data over a region rather than at a point location

Satellite data

The archive radar data were acquired by the ERS–1/2 and ENVISAT satellites for the periods 1992–2000 and 2002–2009 respectively. There is no satellite coverage in the region between 2009 and 2014 due to the orbital decay of ENVISAT. Nonetheless, the period 1992–2009 is sufficient to provide a meaningful baseline assessment of ground motion prior to unconventional gas operations.

For the Vale of Pickering, ESA’s archives include two data stacks of ERS–1/2 and ENVISAT scenes that cover a standard satellite frame extending 100 by 100 km. 75 ERS–1/2 SAR scenes for 1992–2000 and 25 ENVISAT ASAR scenes for 2002–2009 are available. These data (1992–2000 and 2002–2009) have been provided by the European Space Agency (ESA) under grant id. 31573, and analysed by BGS.

A new ESA radar satellite, Sentinel–1A, was launched in April 2014. However, a sufficient stack of data have not yet been acquired by the satellite to carry out high–precision InSAR analysis.

Preliminary results

The ERS (1992–2000) and ENVISAT radar data (2002–2009) have been analysed to produce InSAR results for urban and non–urban areas. Preliminary results from the ERS satellite indicate a maximum average ground motion velocity of 6.25 mm/year (Figure 1) with the majority of the area seemingly stable. Work is ongoing to evaluate the results.

Figure 1. InSAR analysis of satellite data for the Vale of Pickering (ERS data time period 1992–2000; input satellite data provided by ESA under grant id.31573).


Contact

Contact BGS enquiries for further information.