Category Archives: Tectonics

Earthquakes, Tectonics

The 2013 Mw 7.7 Balochistan earthquake in Pakistan: Not so unusual

In 2013, a MW7.7 earthquake struck Balochistan, caused a huge surface offset and triggered a small tsunami in the Arabian Sea.

The apparently strange fault behaviour attracted the attention of scientists worldwide and discussion is still ongoing.

This an interesting case for paleoseismologists, not only because of the cascading earthquake effects, but also because of the surface rupture distribution, from which we might learn some important lessons.

COMET student Yu Zhou and his colleagues from Oxford University have published a new paper on this event, arguing that it might be not as unusual as it seems. Their research is based on the analysis of Pleiades stereo satellite imagery, which has proven to be a very useful data source.

You can read Yu’s blog on the palaeoseismicity.org website.

Earthquakes, Tectonics

Sentinel maps Nepal earthquake

On 25 April, a 7.8-magnitude earthquake struck Nepal, claiming over 8,000 lives and affecting millions of people.

Images from ESA’s Sentinel-1A satellite clearly showed the effects of the earthquake, including the maximum land deformation only 17km from Nepal’s capital, Kathmandu.  This explains the extremely high damage to the area.

Nepal earthquake April 2015. Credit: Copernicus data (2015)/ESA/Norut/PPO.labs/COMET–ESA SEOM INSARAP study
Nepal earthquake April 2015. Credit: Copernicus data (2015)/ESA/Norut/PPO.labs/COMET–ESA SEOM INSARAP study

By combining Sentinel-1A imagery from before and after the quake, COMET scientists have been able to interpret the rainbow-coloured interference patterns in the image (known as an interferogram), and interpret them as changes on the ground.  COMET scientists have also been analysing the 12 May aftershock.  You can read more here.

Earthquakes, Tectonics

Nepal earthquake

COMET scientists have been closely involved with international efforts to analyse satellite data from the recent Nepal earthquake.

Combining two Sentinel-1A radar scans from 17 and 29 April 2015, this interferogram shows changes on the ground that occurred during the 25 April earthquake that struck Nepal. An overall area of 120x100 km has moved – half of that uplifted and the other half, north of Kathmandu subsided. Vertical accuracy is a few cm. Credit: Copernicus data (2015)/ESA/Norut/PPO.labs/COMET–ESA SEOM INSARAP study
Combining two Sentinel-1A radar scans from 17 and 29 April 2015, this interferogram shows changes on the ground that occurred during the 25 April earthquake that struck Nepal. An overall area of 120×100 km has moved – half of that uplifted and the other half, north of Kathmandu subsided. Vertical accuracy is a few cm. Credit: Copernicus data (2015)/ESA/Norut/PPO.labs/COMET–ESA SEOM INSARAP study

You can read more about the Sentinel-1A interferogram on the ESA website.

Links to some of the broader media coverage of our work can be found below.

BBC World Service Science Hour 02.05.15

Listen to Tim Wright describing images of the Nepal earthquake from Sentinel-1A satellite

BBC website 01.05.15

James Jackson, Philip England and Richard Walters are quoted in this article explaining why the Nepal earthquake was so deadly

BBC website 29.04.15

Tim Wright describes the Sentinel-1A interferogram of the area affected by the Nepal earthquake

EOS 27.04.15

James Jackson explains the risks associated with the Nepal earthquake