3 min read

NASA Pinpoints Quake Induced Changes To Earth

Radar images show that an April earthquake near the Mexico-California border caused the Earth's surface to move 31 inches downward and to the south.
NASA this week released the first images of how the Earth's surface was radically altered by an April earthquake near the Mexico-California border.

The agency used radar technology developed by its Jet Propulsion Laboratory in Pasadena, Calif., to show how the quake -- a 7.2 rumbler in Mexico's Baja California state -- actually moved the region surrounding the border city of Calexico, Calif., downward and to the south up to 31 inches.

NASA published the maps of the footage on its Web site.

A team at the JPL used a radar device called the Uninhabited Aerial Vehicle Synthetic Aperture Radar to measure the surface of the Earth to determine changes that can happen after a seismic event. The radar flies at an altitude of 41,000 feet on a Gulfstream-III aircraft from NASA's Dryden Flight Research Center in Edwards, Calif., according to NASA.

To measure the effect of the quake, the JPL created UAVSAR to detect last-minute changes in the distance between the aircraft and the Earth's surface. UAVSAR made repeated flights, guided by GPS technology, to take data measurements, according to NASA.

NASA calculated the quake's effect by combining data from flights on Oct. 21, 2009 and April 13, 2010, creating maps called interferograms from the images UAVSAR took, the agency said.

The April 4 event, called the El-Mayor-Cucapah quake, had its epicenter 32 miles south-southeast of Calexico on the boundary between the North American and Pacific tectonic plates. It was the largest the region felt in nearly 120 years, reaching southern California as well as parts of Nevada and Arizona.

UAVSAR is part of an ongoing effort by NASA to use technologies it's developed for space research, combined with ground technology and computer models, to better understand earthquakes and other geological phenomenon. The radar earlier this year was used to study geological activity after January's massive quake in Haiti, which destroyed a large portion of that country.

The Obama administration increased NASA's funding in its 2011 budget request, but aimed to shift the agency's mission away from rampant space exploration to more earthly concerns -- namely, to use space-based technology to study climate change and other environmental activity on Earth. NASA's JPL has been at the helm of the agency's increased efforts to study earthquakes. The lab recently published the first results of a new tsunami prediction system it developed after a strong quake in February near Santiago, Chile, which was the largest ever recorded by instruments.

NASA said it also hopes to use UAVSAR to evaluate space-based radar technology in development for a mission called the Deformation, Ecosystem Structure, and Dynamics of Ice, or DESDynI. That mission plans to continue the agency's study of earthquakes as well as its research of volcanoes, landslides, and global environmental change.