The Earth is restless — not just above ground, but also deep below the surface. The mantle’s constant movement drives the permanent shifting of the planet's tectonic plates. Most of the time, this activity causes little to no disturbance. But, as the plates move past each other, the pressure builds until one slight change triggers a sudden, monumental shift.

Each year, approximately 500,000 detectable earthquakes occur around the world – only 10,000 of those are probably felt, and less than 100 will probably cause damage. However, it’s the largest damaging earthquakes (probably no more than 10 a year) that cause the greatest concern. These cannot be predicted, and the damage can be disastrous.

Satellite imagery from CSTARS provides real-time, high-resolution imagery especially useful in studying earthquakes. Scientists can precisely measure the motion of the ground and use this information to build or calibrate models to better anticipate and understand these changes.

The most recent great earthquake analyzed with satellite images from CSTARS happened in August 2007 in Peru. With a magnitude of 8.0, this earthquake caused serious damage along the coast of southern Peru; destroying about 80% of the city of Pisco and killing as many as 595 people.

Great earthquakes occur frequently along the Pacific Coast of South and Central America where the Nazca and Cocos plates are sliding under the South American plate. CSTARS regularly collects satellite images across this region to study the latest earthquakes and to measure the subtle movements caused by pressure building up between plates.

Peru, August 2007. Photo credit: Kim Psencik