Space

First direct marsquake data reveals a seismically active Red Planet

First direct marsquake data re...
Artists concept of the InSight lander
Artists concept of the InSight lander
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Artists concept of the InSight lander
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Artists concept of the InSight lander
View from Mars InSight's Instrument Deployment Camera
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View from Mars InSight's Instrument Deployment Camera

The drilling component on NASA’s Mars Insight lander may have hit a snag or two, but this probe has its fingers in a few pies on the surface of the Red Planet. The spacecraft’s primary sensor has now pulled in the first ever direct measurements of seismic activity on Mars, which mission scientists can use as window to better understand the planet’s insides and its potential to harbor life.

The Insight lander touched down on Mars in November of 2018, and less than a month later laid out its main sensor on the surface. This SEIS instrument (Seismic Experiment for Interior Structure) is separate to the self-hammering heat probe that has intermittently become stuck in the surface, though the two are designed to work in tandem to gather new insights on the geological activity of Mars.

Where the heat probe, known as “the mole,” is designed to drill into the surface and measure the thermal conductivity and temperature in the soil, the SEIS will gather data from above the surface. It was the first seismometer to be deployed on Mars in more than 40 years, since the two aboard Viking landers arrived in the 70s, though these were somewhat limited in comparison.

This is because the Viking probes were housed inside the landers where vibrations and winds compromised their performance, with the instruments not returning any convincing data of seismic activity on Mars. The SEIS, in contrast, was carefully placed directly on the planet’s surface by the lander’s robotic arm, with the same arm then placing a protective shield over it a few months later to guard it from the Martian winds and temperature fluctuations that can make for messy signals.

View from Mars InSight's Instrument Deployment Camera
View from Mars InSight's Instrument Deployment Camera

NASA identified what it believed to be the signs of a marsquake last year, and now its painstaking approach is really paying dividends, with the SEIS gathering the first direct evidence of seismic activity on Mars. It collected data over 235 Martian days, revealing 174 seismic events over that time frame. 150 of these marsquakes were high frequency events that resembled those recorded on the Moon during the Apollo program. Promisingly, 24 were low-frequency events and three of those showed waveform patterns similar to those observed on Earth due to shifts in the tectonic plates.

“These low-frequency events were really exciting, because we know how to analyze them and extract information about subsurface structure,” said Vedran Lekic, an associate professor of geology at the University of Maryland and a co-author of the study. “Based on how the different waves propagate through the crust, we can identify geologic layers within the planet and determine the distance and location to the source of the quakes.”

The team’s analysis of these three waveforms enabled them to identify the source location and magnitude of the marsquakes, but it believes at least 10 of them are strong enough to be analyzed and traced in the same way.

“Understanding these processes is part of a bigger question about the planet itself,” Schmerr said. “Can it support life, or did it ever? Life exists at the edge, where the equilibrium is off. Think of areas on Earth such as the thermal vents at the deep ocean ridges where chemistry provides the energy for life rather than the sun. If it turns out there is liquid magma on Mars, and if we can pinpoint where the planet is most geologically active, it might guide future missions searching for the potential for life.”

The research was published in the journal Nature Geosciences, while you can hear from the scientists involved in the brief video below.

Marsquake Sol 235 P and S waves demonstrated by Vedran Lekic and Nick Shmerr

Source: University of Maryland

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