Pop singer Taylor Swift’s song, Shake it Off, took on a whole new meaning after her concert caused an earthquake in Los Angeles last year.
At the time, researchers weren’t sure whether the seismic activity was caused by the sound systems or by the thousands of fans dancing to the music, but a new study by Caltech seismologists has revealed that the fans were to blame.
Swift was performing at SoFi Stadium in August 2023 in front of about 70,000 Swifties — die-hard Taylor Swift fans — when seismologists recorded a magnitude 2.3 earthquake in the city.
It marked the second ‘Swift Quake’ on the West Coast, after Seattle, Washington experienced its own earthquake during her Eras tour concert the month before.
Taylor Swift’s Eras tour caused a 2.3 magnitude earthquake in both Seattle and Los Angeles last year
Swifties caused an earthquake in Seattle and LA by dancing along to the music
Taylor Swift’s song “Shake It Off” provided the most seismic activity from her 45-song set
The California Office of Emergency Services asked scientists to investigate the seismic activity caused by the Seattle concert to determine what exactly happened the night Swifties and the city shook.
Seismologists placed high-powered motion sensors on the night of Swift’s LA performance on August 5 to record where the Swift earthquake originated and which songs were associated with the most seismic activity.
Seismicity is the frequency and severity of an earthquake, although Gabrielle Tepp, co-author of the study and staff seismologist at Caltech Seismic Lab, said their findings looked more like a volcano than an earthquake.
‘For earthquakes they are usually quite sharp and easy to identify with waveforms, but when you have something like volcanoes where you have such a wide variety of signals, spectrograms can be very useful in identifying the different types of earthquakes. signals,” she explained.
Researchers originally thought the earthquake activity was caused by the sound systems and not the fans, and conducted tests to determine which was to blame
Researchers found that every Taylor Swift song generated “a distinct tremor signal.”
‘Shake It Off’ gave the largest magnitude of 0.85 compared to her other songs
The team monitored earthquake gauges from about 5.5 miles (8.8 kilometers) from SoFi Stadium and used spectrograms – a graph that showed the signal intensity, or loudness, of a song.
They found that each Swift song “had a distinct vibration signal.”
“Researchers were able to identify 43 of the 45 songs played within the recorded spectrograms,” the study said.
The spectrogram showed that while all the songs had a seismic impact, Swift’s “Shake It Off” song had the largest magnitude at 0.85.
“Keep in mind that this energy was released over a few minutes, compared to a second for an earthquake of that magnitude,” Tepp said.
“Based on the maximum strength of the shaking, the strongest quake was equivalent to a magnitude -2 earthquake,” she added.
Tepp, who is also an amateur guitarist, said that when she and her team documented their initial results, her “gut feeling was that if you have such a nice harmonic signal, it must be coming from the music or the instruments or something.”
Instead, the researchers discovered that it was the audience’s vibrations moving to the rhythm of the ‘Karma’ singer’s hit music.
They experimented by playing songs on a speaker next to the motion sensor and jumping up and down next to the sensor while Swift’s song “Love Story” played.
Tepp also tried a separate experiment where she plugged her bass guitar into the speaker and played a repetitive beat.
To Tepp’s surprise, the bass guitar did not create a harmonic signal on the sensor, but discovered that jumping around to “Love Story” was the culprit.
‘Even though I wasn’t very good at staying in one place, I ended up jumping around in a little circle, like at a concert. I was surprised at how clear the signal came out,” Tepp said.
The researchers compared their findings to other concerts and found that the summer’s other headliner, Metallica, had the weakest signals of any concert, further leading them to believe that it was the jumping and moving fans at the Swift concert that caused the earthquake with caused a force of 2.3.
“Metal fans like to headbang a lot, so they’re not necessarily bouncing,” Tepp said, adding, “It could just be that the way they move doesn’t send that strong of a signal.”