earthquake

The Kumamoto earthquakes

May 11, 2016

Google has been pushing out imagery updates almost weekly recently. The latest update includes imagery from Kumamoto, Japan, which suffered a series of large earthquakes in April, 2016. Google has managed to capture aerial imagery not just after the event, but during the event. For example, we can see aerial imagery of the slopes of Mt Aso captured on April 15th, and again on April 16th showing that a large number of landslides took place between the images being captured.

Before and after of multiple landslides on Mt Aso, Japan.

Before and after of a landslides that swept over some houses.

A bridge and road destroyed by a landslide.

Some of the landslides channelled together to produce a mudslide at the bottom:

Mudslide caused by landslides on Mt Aso, Japan.

One hillside didn’t quite collapse, but looks very unsafe.

Large cracks across a hillside that has only slid a little bit.

The earthquakes started with a foreshock on April 14th, which struck the eastern Kumamoto suburb of Mashiki. Google was very quick to respond, as the aerial imagery is captured the following day, April 15th. The largest shock took place on April 15th, at 16:25 UTC, which is April 16th, 01:25 JST, so, after the first Google aerial image and before the second one.

Looking at Mashiki, we can see what looks like tiles missing in the roofs of buildings. It is difficult to tell just how much damage has been done. A look at this article, however, shows that many houses collapsed vertically with their roofs largely intact and the real damage was severe.

Collapsed houses in Mashiki, Japan.

In the city of Kumamoto, a bullet train was derailed, but apparently it was not carrying passengers and nobody was hurt. The imagery is dated 15th April, so it appears it was derailed by the foreshock.

Derailed bullet train.

Kumamoto Castle appears to have suffered some damage from the foreshock and then more serious damage in the main quake. There are some relatively poor quality satellite images from after the main quake.

To see the above locations and many more in Google Earth download this KML file.

What’s that image: Earthquake and floods

May 3, 2016

Yesterday we mentioned that Google had pushed out an imagery update towards the end of April. Today we are having a look at some of the sights we have found so far.

On April 16th, 2016, Ecuador experienced an earthquake of magnitude 7.8. Google Earth has three satellite images captured the day after. All three images seem to have a bug where you cannot see the previous image in historical imagery but have to go back two dates to see prior imagery. Perdenales, Ecuador was not far from the epicentre of the earthquake and a number of buildings collapsed. The satellite imagery is not very high quality, but the devastation is visible if you look closely. To identify collapsed buildings, look for rubble in the streets rather than at the buildings, then compare with older imagery. See the fourth image in the slideshow in this story to see an aerial view.

Collapsed buildings in Perdenales, Ecuador.

Further south, in the town of Portoviejo we found a collapsed building as well as signs of minor flooding.

Collapsed building in Portoviejo, Ecuador.

The southern United States seems to have experienced a lot of flooding lately. Earlier this month we had a look at the flooding of the Mississippi River, which took place in January this year. There are now a number of images captured in mid March that show flooding in Texas and Louisiana.

The Sabine River floods Deweyville, Texas.

The Red River in flood near Coushatta, Louisiana.

The Ouachita River, Louisiana.

There are also satellite images of Austin and Houston, Texas, captured on March 12th. We are not sure if they relate to flooding and have not yet identified anything unusual in the images.

There has been further flooding in April, but there is not yet any relevant imagery.

For the locations featured in this post download this KML file. We have included in the KML some data from the USGS showing the epicentre of the quake and the area of impact.

The Oklahoma Earthquakes

March 29, 2016

Starting in 2009 the state of Oklahoma has seen a dramatic increase in seismic activity. According to Wikipedia, it has gone from an average of less than two 3.0+ Mw earthquakes per year to hundreds in 2014 and 2015. This has been caused by increased drilling for oil and the subsequent pumping of waste water into disposal wells deep underground. Read more here. As a result of the increased seismic activity, the U.S. Geological Survey (USGS) has released a new ‘damage map’ showing the risk of damage due to earthquakes significantly increased for the region. Read more about it here and find the map here.

Google Earth has a built in ‘Earthquakes’ layer found in the ‘Gallery’ layer. It only shows earthquakes over 3.0 Mw and as you zoom out it filters out the smaller ones. The result is that when looking at the whole of the continental U.S., Oklahoma doesn’t stand out as being particularly unusual.

However, the ‘Earthquakes’ layer is provided by the USGS and it is possible to obtain more detailed layers directly from them. Go here for automatic live feeds that show recent earthquakes, or here for more advanced queries.

If we choose the “Past 30 Days, M2.5+ Earthquakes” and “Colored by age”, the cluster in Oklahoma immediately becomes apparent:

We can also use the more advanced queries to compare 2008 and 2015:

Earthquakes 2.5+ Mw during 2008.

Earthquakes 2.5+ Mw during 2015.

To see the above in Google Earth download this KML file. The 2008 and 2015 datasets only cover the region around Oklahoma as the USGS website has a limit on the number of quakes allowed in a single query.

Surface deformation after Chile earthquake

September 25, 2015

On September 16th, 2015 a magnitude 8.3 earthquake struck just off the coast of Chile. It was more energetic than the Nepal Earthquake earlier this year, but resulted in far less casualties because Chile has more frequent large earthquakes and is better prepared. For the Nepal Earthquake we showed you a map from NASA showing surface deformation resulting from the earthquake.

Now the European Space Agency has released a similar map showing the surface deformation from the Chile Earthquake.

To see it in Google Earth download this KML file

The ‘Earthquakes’ layer in Google Earth does not show the Chilean earthquake yet. However, the USGS provides up to date KML files on this web page

We chose this one, which shows all earthquakes over magnitude 2.5 from the last 30 days.

As you can see below, the main quake (largest circle) was further south than you might have expected it to be based on the deformation pattern. The cluster of aftershocks, however, do seem to centre on the same location as the deformation pattern.

New Nepal Imagery following May 12th Aftershock

May 22, 2015

Last week we talked about the new imagery in Google Earth following the April 25th Nepal earthquake.

On May 12th Nepal experienced a major aftershock consisting of a magnitude 7.3 earthquake. Just one week later Google Earth already has imagery of Kathmandu and surrounding areas captured on May 14th, 2015.

Left: December 18th, 2014. Right: May 14th, 2015.

Above: A hillside in Sindhupalchowk, north-west of Kathmandu. According to Wikipedia, between the two quakes, 95% of this area’s houses were destroyed.

Left: November 2nd, 2014, Right: May 14th, 2015

Above: The Dharahara tower. Its collapse reportedly killed at least 180 people.

The new May 14th imagery has replaced imagery from May 3rd. Several locations which showed piles of debris from collapsed buildings appear to have been cleaned up since then. We cannot do comparisons as the May 3rd imagery has not yet been put into ‘historical imagery’.

For the locations in this post as well as some other locations we have identified around Kathmandu based on this BBC article download this KML file. For best results, check again in a few weeks when the May 3rd imagery makes it into ‘historical imagery’.