SAR Remote Sensing for Volcanic Hazards: Ground Deformation Monitoring and InSAR

Iceland with the Reyjkanes Peninsula highlighted in red

What is SAR?

SAR is an active sensor thus radar signals are continuously transmitted to the ground then the backscatter is received by the sensor. The brightness of the pixels correlate to the strength of the backscatter received from the terrain. Ground deformation can be monitored by analyzing phase differences between 2 radar imagery.

SAR Timelapse

In the image below we see timelapse animation of the peninsula region using Google Earth Engine and Sentinel-1 SAR GRD imagery. This timelapse data is based on the backscatter strength of the signal. We can see the bright areas are slopes that are facing towards the sensor and urban areas.

Close up of the volcano area. Despite the shifts in the image you can make out the lava flow

Ground Deformation through InSAR

Data was manually downloaded and processed to minimize the geometric distortions seen in the timelapse animations. This would ensure that images are aligned for proper timeseries analysis.

Point 1: Fagradalsfjall Volcano

Point 2: Swelling around Grindavik

For the second point we will look at the area around Grindavik which also has swelling. The Iceland Met office released this displacement map based on data in January 2020:

InSAR displacement map released by Iceland Met office
Sampling point seen by red triangle (left). Timeseries plot of point seen in plot on right.

Concluding Remarks

That the quick glimpse of the activity in Iceland. I hope it showed some interesting insight into how radar remote sensing can be used in our everyday world. This post is related to my previous post about InSAR validation based on GPS data in Iceland.



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Panji Brotoisworo

Panji Brotoisworo

Researcher working on geospatial sciences and general programming