Sightseeing

The fires of Qayyara, Iraq, with Landsat and Sentinel imagery

October 25, 2016

We recently came across this interesting article on Bellingcat which is about the use of environmental damage as a weapon of war in Iraq. As the Islamic State (IS) is being pushed back, they are setting light to oil wells, pouring oil on the streets and in trenches and setting light to it and also setting light to other industrial products such as sulphur.

The article features some Landsat imagery showing the plumes of smoke. Landsat imagery is freely available, and we have in the past created a KML file that can make animations with Landsat imagery. If you download the KML file and view the animation for the area around Mosul, Iraq, you can clearly see the smoke in the last few images. Also of note, you can see some smoke from a previous event in an image from August 2014 to the north west of Mosul. We have also created animations using Sentinel 2 imagery, which you can download here.

The animations above are created using low resolution thumbnails provided on Amazon Web Services (AWS). To see some high resolution imagery, we downloaded the most recent Landsat-8 image and processed it with GIMP using a method similar to the one described here and here.

The result can be seen below:

Landsat 8 image from October 20th, 2016. Note the sulphur fire marked with an arrow. The black smoke is from oil fires.

For comparison, we also downloaded a Sentinel 2 image from September 14th 2016.

Sentinel 2 image from September 14th 2016. This is before the sulphur fire was started. Copernicus Sentinel Data, 2016.

See the above images in Google Earth, download this KML file.

The Bellingcat article also features an image of the sulphur fire from Planet Labs.

‘The Eye’, a rotating island in Argentina

September 2, 2016

We recently came across this article about a floating island in Argentina that rotates. Producer and film director Sergio Neuspiller discovered it when filming in the area and has since started a Kickstarter to raise funds to investigate it further. See the Kickstarter promotion video below:

https://www.youtube.com/watch?v=VfmYEZ8FVAM

The island is visible in Google Earth imagery and has been in existence since at least 2003, the date of the oldest Google Earth image of the location. Here is an animation showing how it moves over time:

It is fairly obvious what is happening (no, it’s not an alien base as some have suggested). When you have a floating island and a water current that flows along one side of it, it will naturally rotate and become circular over time, as well as carving out a circular hole. The phenomenon is quite rare, because the conditions must be just right. Floating islands of plants are themselves quite rare, but in addition, it requires a current, though a fairly slow moving one.

[ Update: We believe wind may be the main factor in some instances rather than current. ]

There is a special type of floating island that is very common and that is ice. The phenomenon does occur with ice, as you can see in the YouTube videos below:

https://www.youtube.com/watch?v=9j6dS9rxbuk

We tried to find other examples of rotating floating islands not made of ice and we found one on a lake in India:

Landslide Dams in Google Earth

August 8, 2016

Landslide dams are formed when a landslide blocks the course of a river, creating a dam. This can lead to catastrophic consequences, as the dam tends to consist of loose easily eroded material and when the lake fills up and overflows the dam, it can lead to catastrophic collapse and flooding.

We recently came across this story about a possible landslide dam on the Yellow River in China nearly four thousand years ago that may have given way and caused catastrophic floods and be the origin of an ancient Chinese flood story. The original scientific study can be found here. We were able to identify the location in Google Earth and it does look like there was once a dam across the gorge between the two arrows shown below:

Jishi Gorge, Yellow River, China

It took us a while to figure out where the photo in the article was taken from until we realised that there is now a dam further downstream and the river is now a lake, which covers the road that is seen in the photo. Also, Google Earth’s terrain is not very accurate at this location, so the mountains don’t look as steep in Google Earth as they are in reality.

Looking on Wikipedia we found that there are a number of other examples of Landslide dams around the world.

There was a landslide in Tajikistan in 1911 that formed Lake Sarez. At 5 kilometres long, 3.2 kilometres wide and up to 567 metres high, it is the tallest natural dam in the world. There is some concern about its stability and the risk of catastrophic flooding in the event of an earthquake.

The landslide dam at Lake Sarez. Water appears to seep through it, forming a river starting at its base.

In 1925 there was a landslide in Wyoming, USA, known as the Gros Ventre landslide that formed Lower Slide Lake. The dam failed in 1927, causing deadly flooding downstream, but much of the dam and the lake remain to this day.

Gros Ventre landslide

In Montana, USA there is Quake Lake, formed when an earthquake triggered a landslide in 1959.

Quake Lake, Montana. The landslide scar is still clearly visible.

A landslide in Pakistan in 2010 formed Attabad Lake

This image was captured just a few months after the landslide. Sadly the older imagery doesn’t quite cover the landslide location.

In 2014 in Nepal there was a landslide that blocked the Sunkoshi river. Due to fears of catastrophic failure a canal was dug through the dam.

Before and after of the Sunkoshi landslide.

Another landslide dam was formed in Langtang valley, Nepal in 2015. There is no relevant imagery in Google Earth yet, but you can see it in Landsat imagery here.

For the above locations and a number of other examples of landslide dams in Google Earth, download this KML file

Cylcone Roanu: Landslide and Floods

June 21, 2016

Cyclone Roanu was, according to Wikipedia, a relatively weak tropical cyclone that, nevertheless, caused severe flooding in Sri Lanka and Bangladesh. In addition, it caused a number of large landslides in Sri Lanka. The only imagery of the event so far in Google Earth is two patches of imagery of Sri Lanka: an image of the capital, Colombo, showing flooding and a set of images further inland showing a landslide.

The images were captured soon after the cyclone so they are rather cloudy and the light is poor.

Flooding in Colombo

Flooding in Colombo.

Much of the landslide is covered in cloud.

Before and after of the tail end of the landslide.

To find the locations shown above in Google Earth, download this KML file.

Two become one, Hunga Tonga and Hunga Ha’apai

June 16, 2016

The recent Google Earth imagery update includes an image of a new island formed from Hunga Tonga and Hunga Ha’apai, part of the Tonga archipelago in the South Pacific Ocean. Hunga Tonga and Hunga Ha’apai used to be two islands with a submarine volcano between them. Then, in December 2014, the volcano started erupting and by mid-January 2015 a new island had formed with the volcano’s crater in the centre. See Wikipedia for more details.

Hunga Tonga and Hunga Ha’apai in 2014, before the 2014/2015 eruption

The new island, May 2016

See ground level photos here.

Another example of islands that have joined together through volcanic eruption that can be seen in Google Earth imagery is Nishinoshima, Japan.

Speed in milliseconds per image:

You can adjust the speed of the animation by dragging the slider.

Find the locations above in Google Earth with this KML file.