Beirut explosion before and after 8 August 2020
A devastating explosion in Beirut on 4 August has killed at least 200 people and injured around 5,000 others.
The disaster was preceded by a large fire at the Port of Beirut, on the city’s northern Mediterranean coast, later there was a colossal explosion that sent a mushroom cloud into the air and a supersonic blast wave radiating through the city.
The blast destroyed the immediate dockside area, creating a crater approximately 140 metres wide, which flooded with seawater. The massive crater at port is also distinguishable in the images of Copernicus EU Sentinel-2 satellite with a optical sensor. The images after and before the explosion, show nearly every building has either sustained significant damage or has been been destroyed by the blast.
Figure-1 : Two view of the destruction caused by an explosion in the port of Beirut was captured by a Capernicus EU Sentinel-2 satellite before 2020/07/24 and after 2020/08/08 the explosion.
The damages was also captured by the Copernicus EU Sentinel-1 with a C-SAR instrument . The following figure shows the coherence map built between two products SAR before (2020/07/31) and after (2020/08/06) the explosion. The two images are commonly called master and slave.
The coherence map shows similarity between pixels master image and pixels slave image in a scale from 0 to 1. Areas of high coherence appear bright. Areas with poor coherence will be dark. For example vegetation having poor coherence and buildings have very high coherence.
Thanks to the coherence map, we can also understand the damage caused by the shock wave that extends well beyond the port area, in fact the image, below, shows a loss of coherence an area of about 4,5 Km ^ 2.
Figure-2: The coherence map shows complete devastation in the port area. The coherence map has been built with two Sentinel-1 products before 2020/07/31 and after 2020/08/06 the explosion. The products are SLC with IW mode and double polarization.
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