In a recent Wired article, I read about a circular region of melted ice that ISS astronauts spotted from space in a Siberian lake. It's almost certainly caused by some upwelling of heat from the Earth's crust, however no one really knows what's going on. For grins, I went and checked out the Google Maps sat view of the region and it's not during the winter. Instead, it shows lots of dark blue water. But when I took a screenshot and ran it through The Gimp's "Colors -> Auto -> Equalize" filter, I got the picture to the right, showing that the region appears in a slightly different color, even when the ice is melted! This is probably due to differences in dissolved gasses or salinity caused by the heat, but I'm no geologist, so I'm not sure. It's just interesting that Google Maps has had this data all along and no one knew.
You'll notice a region to the lower right that is a very different color of blue. It looks like this is a seam between two different sources of images. That's where a more detailed set of (probably aerial) photos begin. The main region is a lower-rez and probably older set of photos that I believe were from the original satellite images that Google Maps began with.
Update 2009-05-27: Similar features can be seen around the northern circle that was identified in the Wired article, when using the Google Maps images. However, much more telling is the fact that the location pictured above was the epicenter of a magnitude 6.2 earthquake late last year. I think that makes it fairly likely that this is a geothermally active area and that the circles could indicate escaping gasses or related events.
Note: the image to the right is from Google Maps, and reproduction of the image is governed by Google's copyright and licensing. It is used here only to illustrate a matter of academic interest.
Nicely done.
ReplyDeleteVery smart!
ReplyDeleteI've seen the story on Wired and there are two spots on the lake. You've covered one of them. I'm curious if you could look at the other spot to see if it's consistent.
ReplyDeletecataliniuga, good point! I'll look when I have time (at work now).
ReplyDeleteAaron, I just took a look at the other circle using your method, and there is a color variation there, but it is not as concentrated and circular as the one you found. However, the sort of color variation that IS there seems unusual and I couldn't find anything quite like it in a few shots in other parts of the lake.
ReplyDeleteYou may be on to something. Could the color variation just be a function of the depth of the lake?
Depth is certainly one factor that could lead to color variation, but as I understand it, the part of the lake we're looking at here is nearly a mile deep... I think that's too deep for us to be seeing significant variations like this. I think it's much more likely to be either direct changes in the chemistry or temperature of this part of the lake or secondary effects of those changes (e.g. algae blooms).
ReplyDelete