[SunkenCiv]

Thanks, but it doesn’t say that more than one event happened in the same place, only that two different amateur astronomers saw the same plume about 10 days apart, and that on other occasions in the past, different plumes were seen, which could easily mean that surface impacts happen on Mars, which has very thin atmosphere (surface pressure on Mars is about the same as 40 miles altitude above Earth).

[Boogieman]

The article doesn't say that, but if you look at the images, it is clearly in the same area, just the 1997 image is flipped vertically (the North pole is on the bottom). Both images show the plume at the same latitude, and right in the same place compared to the dark black streak on the surface near the poles: