On April 23rd, NASA InSight scientists announced they had detected a small seismic event on Mars, aptly referred to as a marsquake. This event, the first of its kind ever detected, promises to bring revolutionary insights about planetary interiors and seismic activity on other worlds.
“InSight’s first readings carry on the science that began with NASA’s Apollo missions,” said InSight Principal Investigator Bruce Banerdt at the Jet Propulsion Laboratory in Pasadena, California. “We’ve been collecting background noise up until now, but this first event officially kicks off a new field: Martian seismology.”
The NASA InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) mission seeks to probe the “inner space” of mars. Using the instruments deployed on its lander, scientists hope to learn about the Martian interior, and on a deeper level, understand how it formed billions of years ago. To this goal, InSight equipped their spacecraft with a French Space Agency seismometer (SEIS), an instrument that measures subtle vibrations in the ground. Over 45 missions have explored the surface of Mars, but InSight is the first to successfully deploy a seismometer.
To send anything into space, it needs to be durable. After surviving a 6-month journey through space to reach the red planet, the SEIS is being exposed to weather beyond anything on earth. From temperatures that can dip down to -225 degrees Celcius, to massive dust storms that can cover the entire planet, Mars is not an ideal spot for a robot vacation.
An artist’s rendering of a potential action thriller about marsquakes. Stay tuned for the sequel, 2 Mars 2 Furious, and the third in the trilogy, Marsquake: Tokyo Drift.
This is because, unlike earth, Mars doesn’t have tectonic plates. Researchers aren’t certain what causes martian seismicity, which is why the installation of the SEIS is so exciting. Quakes on Mars could be from meteor impacts, from magma disturbing the crust as it rises to the surface, or even from the planet slowly cooling and contracting over time.
NASA is so interested in these marsquakes not only for their effects at the surface, but for their insights about what lies beneath. Learning about the interior will help scientists learn how Mars formed; why it’s so similar, yet so alien compared our home.
The key to their geophysical studies is the relationship between seismic energy and the materials it passes through. When a quake occurs, both compressional (P-waves) and transverse (S-waves) waves radiate from the epicenter. These waves travel at different speeds depending on the material they interact with, and notably, S-waves cannot travel through liquids. By looking at how these waves travel through Mars, scientists may learn about the composition, heat flux, and phase dynamics inside of Mars.
One of the many questions on researcher’s minds is how Mars lost its magnetic field. On earth, our magnetic field blocks harmful solar radiation, allowing plants and animals to survive on its surface. Scientists hypothesize that a compositional change in the Martian core destroyed its magnetic field billions of years ago, which is one of the reasons why Mars is uninhabitable. Future studies of these quakes will answer all sorts of questions about our planetary neighbor.
“We are delighted about this first achievement,” said Charles Yana, SEIS mission operations manager at CNES, “and are eager to make many similar measurements with SEIS in the years to come.”