Most visit Yellowstone to see geysers shooting into the sky, but Carol Finn PhD came to see what's beneath them. By flying an airborne geophysical survey, her team uncovered surprises that have changed what we know about the park's iconic thermal features.
"It's really the most famous park in the world," says Carol, a Research Geophysicist with the U.S. Geological Survey.
"We were flying in the off-season when there are no visitors, but the park is used to having a very, very high profile. So, we couldn't have done this without Yellowstone National Park's support."
In 2016, a helicopter took off over Yellowstone with electromagnetic and magnetic survey equipment hanging below. The survey flew line by line across the park building a grid. It covered over 4,200km of line data from the air, all without touching the precious park.
"The electromagnetic instrument allows us to indirectly measure the electrical resistivity of the ground The magnetometer measures the Earth's magnetic field, and we can make corrections to obtain signals from the geology," says Carol.
Their goal was to create a resistivity map of Yellowstone's underground features. Different resistivity values help indicate different materials, primarily fluids, clays, volcanic rocks, and faults. The data would give them an idea of what was beneath Yellowstone, and where.
"The first cross-section we saw from the flights was over the Old Faithful geyser and we could see that the survey worked. We just didn't know what the data meant."
