Measuring the Pulse of Mars

InSight’s seismometer, SEIS, the Seismic Experiment for Interior Structure, was a round, dome-shaped instrument that sat on the Martian surface and took the "pulse" or seismic vibrations of Mars. Its measurements provided a glimpse into the planet’s internal activity. The seismometer waited patiently to sense the pulse, or seismic waves, from marsquakes, and thumps of meteorite impacts. A suite of wind, pressure, temperature, and magnetic field sensors helped fine-tune the seismometer's measurements. This helped it sense surface vibrations generated by weather systems such as dust storms, or by turbulence in the atmosphere due to phenomena such as dust devils, which can also generate seismic waves. SEIS measurements told scientists about the nature of the material that first formed the rocky planets of the solar system.

Tech Specs

"We've been waiting for this moment for a long time. It's been 130 years since the first seismic record on Earth and almost 50 years since a seismometer was placed on the Moon during the Apollo program. What we learn from SEIS will shed light on how Mars formed and evolved."

5 Things to Know

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  First in 40 Years

  InSight delivered the first seismometer to Mars in 40 years. The last time seismometers traveled to the Red Planet was with the Viking landers.
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  Like a Stethoscope

  Like a doctor's stethoscope listening to the patient's heartbeat, SEIS “listens” for marsquakes.
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  Listening to Meteors

  Using the seismometer, scientists could detect meteor impacts over the course of InSight’s mission.
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  Ultra-Sensitive

  SEIS was able to tune in to tremors smaller than a hydrogen atom!
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  Sensing the Weather

  InSight's seismometer was able to sense weather phenomena such as dust devils that produce seismic waves.

How It Worked

SEIS listened for seismic waves on the surface of Mars, shedding light on the interior structure of the Red Planet.

A number of physical phenomena can create seismic waves, including marsquakes, meteorites striking the surface, landslides, or even the pressure of the wind on the surface. Weather phenomena, such as dust devils, can also generate seismic waves.

Waves Change as they Travel

In the way that light changes speed and direction when it passes through water or glass, seismic waves change when they pass through the interior of a planet. How the waves change depends on the material that the interior is made of. SEIS provided scientists with information and how the interior of Mars changes waves, helping them figure out which material changed it.

Waves Tell Stories

Waves from a large quake can travel long distances and pass through many different types of material inside a planet. All of those different materials alter the wave in their own way. To understand what the inside of a planet is really like, SEIS had the ability to listen to a host of different variations in seismic waves clearly. This helped it detect lots of detail about the structure of the layers that changed the waves.

Scientists believe that areas 620 to 1,250 miles (1,000 to 2,000 kilometers) from InSight’s landing site, like the area around Elysium Mons, have experienced volcanism and quakes 1 to 10 million years ago. That’s recent for a planet!