(NASA)
Mars is alive. The InSight probe recorded two marsquakes on the far side of Mars for the first time.
Both events were the largest in magnitude and duration among marsquakes, and one of their sources was the giant canyon system of the Valles Marineris.
.The InSight mission, which landed on Mars in 2018, became the first specialized robot for conducting geophysical research on another planet.
Its main scientific instrument at the moment is the SEIS seismograph, which has been installed next to the station and has been operating for more than three years.
The analysis of the resulting data allows researchers to test models of the internal structure of Mars and determine the properties of various layers of the planet.
Thanks to this information, scientists drew up a diagram of the structure of the subsurface layers of Mars, and determined the main boundaries between its layers
They could also estimate the size of the planet's core, reveal the seasonality of marsquakes and associate some of them with magma activity in the planet's upper mantle.
More marsquakes
Now a group of scientists from the University of Bristol found for the first time seismic events in the SEIS data, which were located on the opposite side of Mars from the station.
Both new quakes are extremely curious, since all previous sources of shocks were concentrated around the Cerberus Furrow fault system, located not so far from the station.
The detected events were designated S0976a and S1000a and were the largest low-frequency marsquakes detected to date, said the geophysicists Anna C. Horleston.
Valles Marineris (NASA/JPL/USGS)
The first (S0976a) was recorded on the night of August 25, 2021, when SEIS recorded the arrival of seismic PP and SS waves. The event had a magnitude of 4.2 and lasted about an hour.
The source of the shocks was in the Valles Marineris, a giant canyon system in the equatorial part of Mars, about 10 million years old.
Scientists previously predicted that the Valles Marineris could show seismic activity due to collapses, landslides and faults.
The second event (S1000a) was recorded on September 18, 2021, it lasted 94 minutes, and has the record for the longest among marsquakes.
The event had a 4.1 magnitude, and the seismograph recorded PP and SS waves. But also recorded the arrival of Pdiff waves with a small amplitude, which crossed the boundary between the core and mantle.
It was not possible to precisely localize the source of shocks in this case.
However, it is known that it is not located near Olympus Mons and may be associated with extensive graben systems to the west of Patera Volcano, which cross basalt plains.
Source:
- The Seismic Record: https://pubs.geoscienceworld.org/ssa/tsr/article/2/2/88/613226/The-Far-Side-of-Mars-Two-Distant-Marsquakes
- Space: https://www.space.com/largest-marsquakes-insight-lander-detection
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