Sentinels map Earth's slow surface warping
http://www.bbc.com/news/science-environment-38323832
Sentinels map Earth's slow surface warping
By Jonathan Amos
BBC Science Correspondent, San Francisco
14 December 2016
From the section Science & Environment
British researchers are now routinely mapping a great swathe of Earth's surface, looking for the subtle warping that ultimately leads to quakes. The team is processing satellite images to show how rocks in a belt that stretches from Europe's Alps to China are slowly accumulating strain. Movements on the scale of just millimetres per year are being sought. The new maps are being made available to help researchers produce more robust assessments of seismic hazard. The kind of change they are trying to chart is not noticeable in the everyday human sense, but over time will put faults under such pressure that they eventually rupture - often with catastrophic consequences.
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Dr Walters is affiliated to the UK Centre for Observation and Modelling of Earthquakes, Volcanoes and Tectonics (COMET). He announced the start of the new service here in San Francisco, at the Fall Meeting of the American Geophysical Union.
Key to the UK scientists' work is the high performance of the EU's new Sentinel-1 radar satellites. This pair of spacecraft repeatedly and rapidly image the surface of the globe, throwing their data to the ground using a high-speed laser link. And by comparing whole stacks of their pictures in a technique known as interferometry, the COMET group can begin to see the very slow bending and buckling that occurs in the crust as a result of shifting tectonic plates.
To initiate the service, the researchers are concentrating on the Alpine-Himalayan seismic belt. This is the sector where most of the deaths arising from big earthquakes occur. In time, however, the mapping exercise will be extended to cover all major seismic hazard zones, including the rim of the Pacific basin - the so-called "ring of fire", where large tremors are also a regular occurrence.
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