The dark patch at both sites: what Zawia3 measured

Zawia3 · Chart 3 of 13

Zawia3 measurements on Sentinel-2 satellite imagery of Eigad and Hangaliya

"This ratio suddenly dropped by 12.2 per cent in the 10 October scene… and in Hangaliya… it dropped by 10.6 per cent on the same day."

Indicator	Eigad	Hangaliya
Area of the dark patch	~4,400 m²44 pixels	~2,800 m²28 pixels
Drop in red reflectance on 10 October	12.2%	10.6%
Distance from the pre-event mean	7.7standard deviations	8.9standard deviations
Distance of patch centre from the published coordinate	18 m	31 m
Pre-event scenes	9	14
Total scenes analysed	12	19

The ground surface changed at both sites between 08:24 UTC on 8 October and 08:24 UTC on 10 October, and did not change between 3 and 8 October.

Standard deviations here are a descriptive measure of how far the value departs from normal, not a test of statistical significance.

Source: Zawia3 measurements on Sentinel-2 satellite imagery (EU Copernicus programme)