47 marsquakes shook volcanic region


Hot rock is still moving beneath what is believed to be an active volcanic region on Mars. This is indicated by a total of 47 possible marsquakes that Weijia Sun from the Chinese Academy of Sciences in Beijing and Hrvoje Tkalčić from the Australian National University in Canberra found in the data from the Marslander InSight. As the two researchers report in Nature Communications, most of the new tremors are similar to two tremors already registered in 2019 in the Cerberus Fossae region, one of the youngest tectonic structures on Mars. According to Tkalčić and Sun, the tremors originate from flows of hot, plastically deformable rock in the Martian mantle. This would indicate that the interior of the planet is far more active than previously thought.

Previously, experts had discovered more than 400 marsquakes in the data from the InSight lander. Most of them, however, were minor tremors in the upper Martian crust or even near-surface stress cracks caused by temperature differences. More interesting are the few tremors that could be due to tectonic processes – in particular S0173a and S0235b, which with magnitudes between three and four relatively clear tremors in Cerberus Fossae. These experts interpreted 2019 as signs of active processes in the region, which also has evidence of recent volcanic activity.

Tkalčić and Sun revisited the InSight data to find more tremors. The data contains a lot of disturbing noise that is superimposed on many signals. Therefore, the researchers used the waveforms of previously measured tremors as a template to identify weak signals – including the two Cerberus Fossae tremors, whose onset and onset of the primary and secondary waves were visible in the data, which facilitated the analysis. In this way, they found 47 other possible tremors, most of them at low frequencies like S0173a and S0235b.



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