InSight team releases a global map of Mars’ seismic zones

Global map of quakes on Mars
Click for original image.

In a new paper that reviewed the entire archive of Mars quakes detected by the seismometer on InSight during its four years of operation on the Martian surface from 2018 to 2022, scientists have now released an updated global map showing the regions on Mars where seismic activity is most common. From the abstract:

Seismicity on Mars occurs mostly along or north of the boundary between the southern highlands and northern lowlands. Valles Marineris is seismically more active than previous catalogs of located events imply. Further, we show evidence that two events likely originate from the Olympus Mons region.

The map to the right is figure 6 from the paper, and shows clearly the sum total of InSight’s data. The yellow triangle marks InSight’s landing spot. The red line delineates the distant quakes from the nearby quakes detected by InSight. The green line is what the scientists identify as the border between the northern lowland plains and the southern cratered highlands. The data suggests that transition point could be linked geologically in some manner to the quakes themselves.

Though the majority of the detected quakes were in the Cerberus Fossae region, the data also suggests two other seismic active regions, one under the giant canyon Valles Marineris and the other south of Mars’ largest volcano, Olympus Mons.

Quakes by InSight indicate Mars’ interior is active

Cerberus Fossae

The first seismic results from InSight’s seismometer now show that the interior of Mars is active, with regular moderately-sized quakes.

The Seismic Experiment for Interior Structure (SEIS) instrument – a seismometer developed by an international consortium under the leadership of the French space agency CNES – recorded a total of 174 seismic events between February and September 2019. Twenty of these marsquakes had a magnitude of between three and four. Quakes of this intensity correspond to weak seismic activity of the kind that occurs repeatedly on Earth in the middle of continental plates, for example in Germany on the southern edge of the Swabian Jura hills.

Although only one measurement station is available, models of wave propagation in the Martian soil have been used to determine the probable source of two of these quakes. It is located in the Cerberus Fossae region, a young volcanic area approximately 1700 kilometres east of the landing site.

Cerberus Fossae is a land of cracks and linear depressions located between the giant volcanoes, Elysium Mons to the north and Olympus Mons to the east. It is believed those fissures were caused by the rise of those volcanoes, stretching the crust and cracking it.

This new data from InSight strengthens this theory.