Measuring earthquakes from optical satellite images.

Area of Science:

• Geodesy
• Remote Sensing
• Seismology

Background:

• Earth observation satellite imagery is crucial for monitoring geological events.
• Quantifying ground deformation from seismic activity requires precise measurement techniques.

Purpose of the Study:

• To develop and validate a method for accurately mapping earthquake-induced ground displacements using Système pour l'Observation de la Terre (SPOT) images.
• To assess the accuracy of the developed method for fault mapping and displacement measurement.

Main Methods:

• Compensation of image deformations from stereoscopic effects and satellite/detector artifacts.
• Resampling images to a cartographic projection using a low-bias interpolator.
• Utilizing a subpixel correlator in the Fourier domain for 2D offset mapping with ~160 m resolution.
• Bias compensation through calibration and noise reduction techniques.

Main Results:

• Achieved high-accuracy 2D offset maps with subpixel precision.
• Demonstrated fault mapping accuracy within tens of meters for the Landers earthquake.
• Measured fault displacement with an accuracy better than 20 cm.
• Identified and compensated for various sources of image deformation and noise.

Conclusions:

• The developed method enables precise mapping of earthquake-induced ground displacements using SPOT imagery.
• The technique provides valuable data for understanding seismic faulting mechanisms, complementing traditional geodetic models.
• Offers a cost-effective and accessible approach for high-resolution earthquake deformation analysis.