Today we are looking at a few more locations around the world.
Italy suffered two major earthquakes last year in August and October, which we have covered previously (August earthquake, October earthquake. There is now some DigitalGlobe imagery of some of the worst affected areas.
Amatrice, Italy was near the epicentre of the August earthquake.
On November 14, 2016, the South Island of New Zealand experienced a 7.8 magnitude earthquake named the Kaikoura Earthquake after the town of Kaikoura near the quake’s epicentre. The affected region is mountainous with steep slopes and the earthquake resulted in a large number of landslides, including creating some landslide dams (a topic we have covered in the past).
The Landslide Blog has done a number of posts on the Kaikoura landslides (1, 2, 3 and 4). It also mentions this article, which shows a map of the locations of the landslides so far identified using Sentinel 2 imagery.
We thought it would be interesting to examine the sentinel 2 Imagery in Google Earth. The image in question has quite a lot of cloud cover, but in the gaps between the clouds we can see the scars of a large number of landslides. It must be noted that landslides appear to be common in the region, with many landslide scars being visible in older imagery, too. Here are a couple of ‘before and afters’ showing just how many landslides there were in some places.
Italy has again suffered a series of earthquakes, with the largest occurring this past Sunday, October 30th, 2016. The earthquakes were centred just north west of the locations of the August earthquakes. However, if you enable the Google Earth ‘Gallery->Earthquakes’ layer, there is no trace of either of these events. The earthquakes layer has always been restricted to large earthquakes, but the Sunday earthquakes at a preliminary magnitude 6.6s was the largest in Italy in 36 years. We also had a look for the Japanese Kumamoto Earthquake form April and that too is not in the layer, so it would appear the layer has not been updated for some time.
When layers like this are broken, Google should consider either fixing the layer, or, as they did with the weather layers, remove the layer altogethers so as to not cause confusion.
The data for the layer comes from the USGSs which provides KMLs of earthquake data which you can find here. Those KMLs are kept up to date and do show the recent Italian quakes, although a layer called ‘tectonic plates’ that is in the KMLs does not work.
Use the KMLs provided directly by the USGS to find earthquakes in Google Earth and not the built in layer.
Note that if you choose one of the animated KMLs, you must click the play button on the time toolbar in order to see the earthquake markers. You may also want to slightly separate the two sliders a in the time toolbar for the best results.
We have not yet found any imagery for these latest earthquakes available for Google Earth. However, the Copernicus Emergency Management Service does provide imagery in the form of downloadable images of the main affected areas. The images vary in quality and are mostly marked with damage assessments, so it is difficult to see the actual damage in the imagery. In addition, much of the imagery was captured and analysed before Sunday’s earthquake, which was the largest.
In April this year, the city of Kumamoto, Japan, suffered a series of large earthquakes. Google managed to capture aerial imagery of the city essentially during the event, after the first major event but before the largest shock and then captured another set of imagery from after the event. We had a look at what damage could be seen in the imagery, including a large number of landslides, collapsed buildings and a derailed train. From the overhead imagery it wasn’t easy to see the extent of the damage to buildings, even though we knew, based on ground level imagery, that there was severe damage in some locations. Now Google has updated the 3D imagery for part of Kumamoto with imagery captured after the event, and the extent of the damage to buildings is much clearer, especially because the roofs have been patched with light blue tarpaulin that is highly visible.
The suburb of Mashiki was the worst hit, and many houses are damaged beyond repair.
A historical building known as Janes’ Residence was completely destroyed. The rubble has been covered in the light blue tarpaulins
The Janes’ Residence was the first western-style house built in Kumamoto dating from 1871. It used to be in the grounds of Kumamoto Castle, but has been moved a number of times. Read more about it here.
Kumamoto Castle was badly damaged by the earthquake.
We have also created a Google Earth tour of the area showing all the light blue roofs, which you can view in Google Earth with this KML file or see in the YouTube video below.
As of this writing, Google has not updated ‘historical imagery’ for almost three months. Up until mid-June they had been updating it almost weekly. As a result, there have been a lot of events over the past few months that we know were captured by DigitalGlobe but we cannot access the imagery in Google Earth. One such event was the deadly earthquake that struck central Italy on August 24th, 2016.
Google has provided an image of the region from one of Terra Bella’s SkySat satellites. It can be viewed in Google Earth using this KML file. They SkySat satellites are not as high resolution as most Google Earth satellite imagery, but in this case, some of the affected regions in Italy do not have high resolution satellite imagery – all they have is SPOT imagery, which is lower resolution than the SkySat imagery. Despite the relatively low resolution, we can see some of the effects of the earthquake in the imagery.
Before image: CNES/Spot Image. After image: Google / Terra Bella. Amatrice, Italy. 1: The location of most of the damaged buildings. 2 & 3: Tents set up after the disaster.
We also saw tents in Grisciano in the Terra Bella image.
Also worth looking at is the Copernicus Emergency Management Service. They gathered satellite imagery of the affected region almost immediately after the earthquake and within a day or two had arranged aerial imagery too. The results can be seen on this page. There are maps of the affected towns, including grading the amount of damage down to building level. For example, you can see the map for Amatrice in this PDF.
Sentinel-1A and Sentinel-1B are radar satellites that are particularly good at detecting changes in terrain. You can see deformation maps in this article that uses images from before and after the event to detect how much the ground had moved after the earthquake.