Caltech: NASA Balloon Detects California Earthquake – Next Stop, Venus?

Between July 4 and July 6, 2019, a sequence of powerful earthquakes rumbled near Ridgecrest, California, triggering more than 10,000 aftershocks over a six-week period. Seeing an opportunity, researchers from NASA’s Jet Propulsion Laboratory and Caltech flew instruments attached to high-altitude balloons over the region in hopes of making the first balloon-borne detection of a naturally occurring earthquake. Their goal: to test the technology for future applications at Venus, where balloons equipped with science instruments could float above the planet’s exceedingly inhospitable surface.

And they succeeded. On July 22, highly sensitive barometers (instruments that measure changes in air pressure) on one of the balloons detected the low-frequency sound waves caused by an aftershock on the ground.

In their new study, published on June 20 in Geophysical Research Letters, the team behind the balloons describes how a similar technique could help reveal the innermost mysteries of Venus, where surface temperatures are hot enough to melt lead and atmospheric pressures are high enough to crush a submarine.

“Much of our understanding about Earth’s interior – how it cools and its relationship to the surface, where life resides – comes from the analysis of seismic waves that traverse regions as deep as Earth’s inner core,” says Jennifer M. Jackson, the William E. Leonhard Professor of Mineral Physics at Caltech’s Seismological Laboratory and a study co-author. “Tens of thousands of ground-based seismometers populate spatially-dense or permanent networks, enabling this possibility on Earth. We don’t have this luxury on other planetary bodies, particularly on Venus. Analysis of surface features on Venus suggest recent volcanic activity and some regions appear reminiscent of subduction zones. Observations of seismic activity there would strengthen our understanding of rocky planets, but Venus’ extreme environment requires us to investigate novel detection techniques.”