Land subsidence caused by the East Mesa Geothermal Field, California, observed using SAR interferometry

TLDR

Interferometric combination of ERS‑1 SAR images maps the deformation field of the East Mesa geothermal plant in southern California. SAR interferometry is applied over this flat area without a digital terrain model, using multiple image pairs to characterize the phenomenon. Short‑term interferograms show surface phase changes on agricultural fields, while two‑year data reveal land subsidence consistent with sparse levelling, demonstrating the technique’s accuracy and potential for legal use.

Abstract

Interferometric combination of pairs of synthetic aperture radar (SAR) images acquired by the ERS‐1 satellite maps the deformation field associated with the activity of the East Mesa geothermal plant, located in southern California. SAR interferometry is applied to this flat area without the need of a digital terrain model. Several combinations are used to ascertain the nature of the phenomenon. Short term interferograms reveal surface phase changes on agricultural fields similar to what had been observed previously with SEASAT radar data. Long term (2 years) interferograms allow the study of land subsidence and improve prior knowledge of the displacement field, and agree with existing, sparse levelling data. This example illustrates the power of the interferometric technique for deriving accurate industrial intelligence as well as its potential for legal action, in cases involving environmental damages.