Uncovering the Origin of Mars’ Most Powerful Recorded Quake

On Wednesday, May 4, 2022, NASA’s InSight lander detected a seismic event of remarkable proportions, registering at a magnitude of 4.7. This seismic episode sent tremors resonating across the Martian landscape for a continuous duration of at least six hours. Given the resemblance of its seismic signature to past quakes linked with meteoroid impacts, the research team initially entertained the possibility that this occurrence, labeled ‘S1222a,’ might also have stemmed from an impact. This led to the launch of a global quest to locate a potential new impact crater.

While Mars may be smaller in size compared to Earth, its land surface area is surprisingly similar due to the absence of oceans. To effectively scrutinize this vast expanse spanning 144 million square kilometers, Dr. Benjamin Fernando, leading the study and hailing from the University of Oxford’s Department of Physics, embarked on a unique collaborative endeavor. Contributions and cooperation were sought from a spectrum of space agencies including the European Space Agency, the Chinese National Space Agency, the Indian Space Research Organisation, and the United Arab Emirates Space Agency. Remarkably, this marks the maiden occasion where all Mars-orbiting missions have united forces for a singular research undertaking.

Throughout its tenure on Mars, InSight, a mission co-designed in collaboration with the University of Oxford, meticulously documented no fewer than eight seismic events attributed to meteoroid impacts. Notably, the most substantial pair among these resulted in the formation of craters approximately 150 meters in diameter. Should event S1222a indeed have originated from an impact, the anticipated crater size would surpass 300 meters in diameter. To investigate this, each research team extensively scrutinized data sourced from their respective satellites encircling Mars in the quest to identify fresh craters or any distinctive signs of an impact, such as the emergence of a post-quake dust cloud.

Following an exhaustive search spanning several months, the research team disclosed their findings today, revealing that they failed to uncover any evidence of a new impact crater. As a result, they have reached the compelling conclusion that the seismic event, previously designated as S1222a, stemmed from the release of immense tectonic pressures within the depths of Mars. This revelation stands as a testament to the planet’s heightened seismic activity, defying prior assumptions about its geological dynamics.

We still think that Mars doesn’t have any active plate tectonics today, so this event was likely caused by the release of stress within Mars’ crust. These stresses are the result of billions of years of evolution; including the cooling and shrinking of different parts of the planet at different rates. We still do not fully understand why some parts of the planet seem to have higher stresses than others, but results like these help us to investigate further. One day, this information may help us to understand where it would be safe for humans to live on Mars and where you might want to avoid!

This project represents a huge international effort to help solve the mystery of S1222a, and I am incredibly grateful to all the missions who contributed. I hope this project serves as a template for productive international collaborations in deep space.

Benjamin Fernando
Department of Physics, University of Oxford

This experiment shows how important it is to maintain a diverse set of instruments at Mars, and we are very glad to have played our part in completing the multi-instrumental and international approach of this study.

Daniela Tirsch
Science Coordinator for the High Resolution Stereo Camera on board the European Space Agency’s Mars Express Spacecraft

We are willing to collaborate with scientists around the world to share and apply this scientific data to get more knowledge about Mars, and are proud to have provided data from the colour imagers on Tianwen-1 to contribute to this effort.

Jianjun Liu
National Astronomical Observatories, Chinese Academy of Sciences

This has been a great opportunity for me to collaborate with the InSight team, as well as with individuals from other major missions dedicated to the study of Mars. This really is the golden age of Mars exploration!

Dimitra Atri
Group Leader for Mars at New York University Abu Dhabi and contributor of data from the UAE’s Hope Spacecraft

S1222a marked one of the final seismic episodes documented by InSight, just before its mission was officially concluded in December 2022. The team is now leveraging the insights gleaned from this study, directing their newfound understanding towards forthcoming endeavors, including missions slated for the Moon and Saturn’s enigmatic moon, Titan.

Resources

1. ^NEWSPAPER University of Oxford News. (2023, October 17). New study reveals source of largest ever Mars quake. University of Oxford News. [University of Oxford News]
2. ^JOURNAL Fernando, B., Daubar, I. J., Charalambous, C., Grindrod, P. M., Stott, A., Al Ateqi, A., Atri, D., Ceylan, S., Clinton, J., Fillingim, M., Hauber, E., Hill, J. R., Kawamura, T., Liu, J., Lucas, A., Lorenz, R., Ojha, L., Perrin, C., Piqueux, S., Stähler, S., Tirsch, D., Wilson, C., Wójcicka, N., Giardini, D., Lognonné, P., & Banerdt, W. B. (2023). A Tectonic Origin for the Largest Marsquake Observed by InSight. Geophysical Research Letters, 50(20). [Geophysical Research Letters]