The Ground Beneath Joyce: What Seismology Tells Us About the Captive Elephants at Six Flags

For 15 years, Joyce the elephant has lived just steps away from the roaring rollercoasters and heavy vehicle routes of Six Flags Wild Safari in New Jersey. Though millions of visitors pass through the park each year, few realize that an elephant, one of Earth’s most vibration-sensitive mammals, is living in an environment filled with mechanical rumbling, shaking, and noise far beyond what she would ever experience in the wild. 

To understand what Joyce endures, World Animal Protection partnered with Terrapin Sensing and researchers at the University of Maryland’s Seismology Department to conduct the first seismic study of its kind at a US theme park. Over 30 days between July 12 and August 12, 2025, scientists deployed sensitive seismometers at eight locations near the amusement and safari parks to measure the intensity, frequency, and sources of ground vibrations around Joyce’s enclosure. The results paint a troubling picture of life in captivity. 

A Landscape of Shaking Ground 

The data confirmed three major sources of continuous ground motion around Joyce:

• Rollercoasters generating vibrations between 5–20 Hz, the same range elephants naturally use to communicate across long distances.

• Safari trucks creating frequent vibrations between 20–200 Hz as they rumble past her enclosure throughout the day.

• A nearby water treatment plant producing a steady mechanical hum in the 7–10 Hz range. 

According to the Modified Mercalli Intensity Scale, these vibrations fall roughly between Level IV and Level V, similar to what humans feel during a small earthquake or the impact of a heavy truck striking a building. In other words, the ground beneath Joyce isn’t just shaking occasionally. It moves often, and sometimes dramatically.

Why Vibrations Matter for Elephants 

Elephants are profoundly attuned to low-frequency vibrations, which they sense through their feet. In the wild, these vibrations help them communicate with herd members miles away, detect danger, and navigate their environment. Their sensory world depends on subtle, natural vibrations, not the unrelenting mechanical noise of a theme park. 

Scientists don’t yet know exactly how elephants experience or interpret constant artificial vibration. But they do know this: elephants evolved to choose whether to approach or avoid ground motion. In captivity, Joyce has no such choice. 

As Dr. Jan Schmidt-Burback, World Animal Protection’s Director of Wildlife Research and Veterinary Expertise, explains: 

“Elephants in the wild may choose to avoid such vibrations, but in captivity they have no such choice. As long as the impact of these vibrations can’t be disproven, we must err on the side of caution and assume that measurable, artificial noise does have an impact on elephants and should be avoided as much as possible. This adds to the long list of concerns for why a theme park in a cold climate environment, with truck-based observation on roads and rollercoasters nearby, is clearly not the right environment for elephants such as Joyce.”

A Clear Path Forward 

This seismic study confirms what many advocates have long feared: Joyce’s enclosure is embedded in a landscape of continuous and powerful ground disturbances. For an elephant, this environment is not just inadequate, it’s harmful. 

It’s time for Joyce and the other elephants at Six Flags to be moved to an accredited sanctuary where they can live in peace, choose how they engage with their environment, and finally experience the freedom they deserve. 

Join us in calling on Six Flags to do the right thing. Urge Six Flags to retire Joyce to a reputable elephant sanctuary, because no animal should live their life in a world that never stops shaking.

Act Now