Leonard David's INSIDE OUTER SPACE

Image credit: Nicolas Sarter/Université Paris Cité/CNRS

A detailed look at both orbital and seismological data gathered at Mars point to a clear increase in the number of dust avalanches around the epicenters of two “Marsquakes.”

The seismic events were recorded during the NASA InSight lander mission to the Red Planet that performed duties at Elysium Planitia from May 2018 to the end of 2022.

“The first seismic event was caused by an impactor hitting the Martian surface. The second seismic event was the largest marsquake ever recorded. This finding sheds light on how endogenous and exogenous processes can currently shape the surface of Mars and trigger active mass wasting.”

The research findings have been reported by Antoine Lucas, a research scientist at the Institut de physique du globe de Paris in France. 

Meteorite impact

Lucas and colleagues explain that the first seismic event under investigation, named S1000a, occurred on September 18, 2021. At that time, a meteorite impact led to a seismic signal registering a local Martian magnitude of 4.1, resulting in the formation of a crater approximately 500 feet (150 meters) in diameter.

A comparison of before and after orbital images of the area reveals a massive increase in new dust avalanches within a 12 mile (20 kilometers) radius of the epicenter, likely caused by intense surface acceleration and atmospheric blast. “To date, this is by far the largest number of avalanches triggered by an impact that has been spotted,” Lucas and the research team point out.

A sequence of images captured 8 months prior to S1222a and taken shortly after the marsquake.
Image credit: A. Lucas, et al.

Connection to ancient volcano?

The second seismic event, named S1222a, took place on May 4, 2022 and was the largest marsquake ever recorded. Estimated at a magnitude of 4.7, the rattle occurred near the Apollinaris volcano, with the epicenter estimated to lie at a depth of less than 12 miles (20 kilometers).

“Despite its energy being approximately 25 times greater than the S1000a impact event, orbital data reveal more gentle number of new avalanches. Nonetheless, the comparison of orbital images since 2005 with high-resolution images post-S1222a reveals a significant rise in avalanche occurrence, from 3% to 40% in certain areas, over one Martian year (equivalent to 687 Earth days).”

There are two potential interpretations of the Marsquake’s mechanism: a connection to the ancient volcano, Apollinaris Patera, although its current activity is deemed improbable. The second hypothesis posits a large geological structure — a 450 km-long ridge — as the probable seismic source, situated adjacent to the estimated epicenter location, the researchers explain.

This image shows InSight’s domed Wind and Thermal Shield that covers the Seismic Experiment for Interior Structure (SEIS) seismometer.
Image credit: NASA/JPL-Caltech

Groundwork ahead

“These findings not only lay the groundwork for future investigations into Martian seismic activity and its influence on surface and subsurface processes but also underscore the significance of surface process analysis in elucidating the mechanisms driving the Red Planet’s seismic phenomena,” the investigators conclude.

Along with the InSight recordings, data used was gleaned from the European Space Agency’s Mars Express as well as cameras aboard NASA’s Mars Reconnaissance Orbiter.

For more information, go to — “Possibly seismically triggered avalanches after the S1222a Marsquake and S1000a impact event” — at:

https://www.sciencedirect.com/science/article/abs/pii/S0019103523005213

Also, go to this animation with credits to Nicolas Sarter (illustration)/Antoine Lucas (animation), viewed at: 

https://www.ipgp.fr/wp-content/uploads/2024/01/Animation_avalanche.gif