Dr Adam Stinton Montserrat Volcano Observatory provided the following explanation.

In the middle of the image is the large depression that is the summit crater that used to contain the lava domes from 1979 and 2021.

The explosions that began on 9 April 2021 have destroyed both domes, creating a smaller crater that measures about 800 m in diameter.

The base of this crater is very distorted in the image due to the presence of ash in the air, the ongoing eruption and the way that radar images are acquired.

Radar images are not photographs. They are created by bouncing radio waves off the Earth’s surface and recording the intensity and size of the returning signal.

Radiowaves are capable of penetrating through the ash plumes and weather clouds that are currently covering the volcano and preventing other satellites from acquiring photograph-like images.

The variation in brightness in this greyscale image is related to the strength of the returning signal. The distortion in the image is because the radio waves are emitted from the satellite at an angle and not vertically downwards.

North in the image is to the upper left corner. Image: @capellaspace Analysis: Dr Adam Stinton