Upon studying the images from those days and other days, I could not find any evidence of a blackened area and plus the images on the EOSDIS Worldview website are not clear enough as there's only so much you can zoom in. When looking at images from the Earthexplorer website (you can download better resolution pics and zoom in), I found what appeared to be a plume with slight ash content on an image from 17th April plus what appeared to be some slight incandescence in the crater area. However, it was partially cloudy in that image so it was overall not easy to determine whether an eruption took place or not.
So I would deem this event inconclusive.
|What appears to be a gas plume extending northwest from Saunders Island in the image from 23rd April. SOURCE: NASA.|
|What appears to be a greyish plume rising from the summit area in the image from 24th April. Was it dense degassing? was it an ash plume? SOURCE: NASA.|
|Not easy to tell when it's partially cloudy. SOURCE: Landsat 8/USGS/NASA.|