Enlarge / Taylor Swift during her Eras Tour. Crowd motions likely caused mini "Swift quakes" recorded by seismic monitoring stations. (credit: Ronald Woan/CC BY-SA 2.0 )

When mega pop star Taylor Swift gave a series of concerts last August at the SoFi Stadium in Los Angeles, regional seismic network stations recorded unique harmonic vibrations known as "concert tremor." A similar "Swift quake" had occurred the month before in Seattle, prompting scientists from the California Institute of Technology and UCLA to take a closer look at seismic data collected during Swift's LA concert.

The researchers concluded that the vibrations were largely generated by crowd motion as "Swifties" jumped and danced enthusiastically to the music and described their findings in a new paper published in the journal Seismological Research Letters. The authors contend that gaining a better understanding of atypical seismic signals like those generated by the Swift concert could improve the analysis of seismic signals in the future, as well as bolster emerging applications like using signals from train noise for seismic interferometry .

Concert tremor consists of low-frequency signals of extended duration with harmonic frequency peaks between 1 and 10 Hz, similar to the signals generated by volcanoes or trains. There has been considerable debate about the source of these low-frequency concert tremor signals: Are they produced by the synchronized movement of the crowd, or by the sound systems or instruments coupled to the stage? Several prior studies of stadium concerts have argued for the former hypothesis, while a 2015 study found that a chanting crowd at a football game produced similar harmonic seismic tremors. However, a 2008 study concluded that such signals generated during an outdoor electronic dance music festival came from the sound system vibrating to the musical beat.

Enlarge / The Reykjanes Peninsula in Iceland is mostly a barren waste of lava fields. (credit: Vincent van Zeijst/CC BY 3.0 )

Intensifying seismic activity these past few weeks along Iceland's southwestern Reykjanes Peninsula —marked by tens of thousands of earthquakes, as many as 1,400 within one 24-hour period—has experts warning of a likely volcanic eruption at any time. While such activity is typically monitored by seismometers, seismologists at Northwestern University are also listening to the data collected by the region's Global Seismographic Network station using an app they developed a few years ago called Earthtunes .

With the app , those earthquakes can sound like slamming doors or hail pelting a window or roof. “The activity is formidable, exciting, and scary,” said Suzan van der Lee , a Northwestern seismologist who co-developed Earthtunes. “Iceland did the right thing by evacuating residents in nearby Grindavik and the nearby Svartsengi geothermal power plant.”

Sonification of scientific data is an area of growing interest in many different fields. For instance, several years ago, a project called LHCSound built a library of the “sounds” of a top quark jet and the Higgs boson, among others. The project hoped to develop sonification as a technique for analyzing the data from particle collisions so that physicists could “detect” subatomic particles by ear. Other scientists have mapped the molecular structure of proteins in spider silk threads onto musical theory to produce the "sound" of silk in hopes of establishing a radical new way to create designer proteins. And there's a free app for Android called the Amino Acid Synthesizer that enables users to create their own protein "compositions" from the sounds of amino acids .

Enlarge / InSight captured seismic waves released when an impact formed this crater in 2021. But a similar event can't be tied to any craters.

Earth has earthquakes. Mars has marsquakes . There is just one difference: marsquakes are most frequently caused by meteoroid crashes since the Red Planet lacks the tectonic plates that shift pieces of crust on Earth. So what caused the most intense marsquake ever when there has been no evidence of a collision?

Vibrations from the 4.7 magnitude quake sent tremors through the Martian crust for six hours (if not more) and were captured by NASA’s InSight lander in May 2022. Otherwise known as S1222a, this marsquake was assumed to have been caused by a meteoroid impact , so an international team of researchers immediately began searching for evidence of a fresh crater. The problem was that none existed. That's when the team, led by planetary geophysicist Benjamin Fernando, began thinking that something was potentially going on beneath the surface.

“We undertook a comprehensive search of the region in which the marsquake occurred,” Fernando and his team said in a study recently published in Geophysical Research Letters . “We did not identify any fresh craters in the area, implying that the marsquake was likely caused by geological processes.”

Enlarge / This view from an international volcano monitoring system shows the Kolumbo volcanic crater on the seafloor. (credit: SANTORY )

In 1650 CE, the Greek island of Santorini was devastated by the eruption of an underwater volcano called Kolumbo . People first noticed the water boiling and changing color and a cone poking out of the surface of the sea. Next came ejected glowing rocks, fire and lightning, fumes of thick smoke, falling pumice and ash, earthquakes, and a powerful tsunami with waves as high as 20 meters. All this eruptive activity killed around 70 people and hundreds of cattle.

These details are based on contemporary accounts compiled by French geologist Ferdinand A. Fouqué in 1879. A team of German and Greek scientists has now combined that historical knowledge with 3D seismic mapping and computer simulations to determine why the volcano's violent eruption triggered a tsunami. According to a new paper published in the journal Nature Communications, the tsunami resulted from a landslide followed by the volcanic explosion.

Located some 8 kilometers northeast of Santorini, Kolumbo also erupted around 1630 BCE with catastrophic consequences for ancient Minoan culture. Today, the volcano boasts sulfide-sulfate hydrothermal vents that are home to some rare species of microorganisms typically not found elsewhere near hydrothermal vents. And it remains active and potentially dangerous: A previously unknown magma chamber was discovered last year and is growing at a rate of around 4 million cubic meters per year. At that rate, the chamber will reach the same volume as the amount of magma ejected in the 1650 eruption within the next 150 years.

Enlarge / Deployment of LSPM junction box 1. (credit: IN2P3/CNRS)

In 1962, one of the world's first underwater research laboratories and human habitats was established off the coast of Marseilles, France, at a depth of 10 meters. The Conshelf 1 project consisted of a steel structure that hosted two men for a week.

Now, more than 60 years later, another underwater laboratory is being set up not far from Marseilles, this time to study both the sea and sky. Unlike the Conshelf habitat, the Laboratoire Sous-marin Provence Méditerranée (LSPM) won't be manned by humans. Located 40 km off the coast of Toulon at a depth of 2,450 meters, it is Europe’s first remotely operated underwater laboratory.

Physics under the sea

Currently, three junction boxes capable of powering several instruments and retrieving data are at the heart of LSPM. The boxes, each measuring 6 meters long and 2 meters high, are connected to a power system on land via a 42-kilometer-long electro-optical cable. The optical portion of this cable is used to collect data from the junction boxes.

Enlarge (credit: Sefa Kart/Getty)

Android phones around San Francisco’s Bay Area buzzed with an alert on Tuesday morning: A 4.8 magnitude earthquake was about to hit. “You may have felt shaking,” some of the messages read. More than a million Android users saw the alert. And for some, it arrived seconds before the ground even started moving.

It’s not the first time Android devices have received these alerts, says Marc Stogaitis, the project lead for the Android Earthquake Alerts System. But because the Bay Area is so densely populated, the alert hit enough phones that the larger public took notice. Earthquakes have historically come without warning, catching people off guard and leaving them with no advance notice to drop and take cover. Alerts like this aim to take some of the unpredictability out of earthquakes—even if by just a few seconds.