From Wired magazine, see this article titled New Technology for Mapping Earthquakes. Some excepts:

The Nepal earthquake on Saturday devastated the region and killed over 2,500 people, with more casualties mounting across four different countries. The first 24 hours of a disaster are the most important, and first-responders scramble to get as much information about the energy and geological effects of earthquakes as they can. Seismometers can help illustrate the location and magnitude of earthquakes around the world, but for more precise detail, you need to look at three-dimensional models of the ground’s physical displacement.

The easiest way to characterize that moving and shaking is with GPS and satellite data, together called geodetic data. That information is already used by earthquake researchers and geologists around the world to study the earth’s tectonic plate movements—long-term trends that establish themselves over years. But now, researchers at the University of Iowa and the U.S. Geological Survey (USGS) have shown a faster way to use geodetic data to assess fault lines, turning over reports in as little as a day to help guide rapid responses to catastrophic quakes.

Thanks to Ian McLean for the citation.

Here is another article about the same topic. See: Satellite images reveal Mount Everest lost one inch of its height in the Nepal earthquake, but Kathmandu has been lifted by more than three feet

• The satellite, Sentinel-1a, sends out radio waves and times how long it takes for them to reflect back
• The data has been transformed into an ‘interferogram’ showing how the land mass has shifted
• Scientists count the colored ‘fringes’ in the interferogram to detect how much the land has moved
• Everest lost an inch of its height in the quake, but still stands at 29,029 feet
  An area 75 miles by 30 miles around Kathmandu has risen over three feet