The seismometer aboard the InSight lander recorded two earthquakes of magnitude 4 or greater in the far side of the red planet.
Simulation of the InSight lander on Mars. Image: NASA
According to a report in the magazine The Seismic Record On April 22, seismic events named S0976a and S1000a occurred only 24 days apart, on August 25, 2021 and September 18, 2021, respectively, but were only recently confirmed when the Researchers from the UK’s University of Bristol analyze the trove of data collected by the InSight spacecraft.
S0976a’s tremors originate in the Valles Marineris region – a massive network of canyons that make up one of Mars’ most recognizable geological features and one of the largest trench systems in the solar system. . Previous satellite images of transverse faults and landslides have shown the area to be seismically active, but S0976a is the first earthquake event detected here. With a magnitude of 4.2, it was the strongest earthquake ever recorded on the red planet.
The second event, S1000a, produced a 4.1 magnitude tremor. The researchers weren’t able to pinpoint its exact location, but like S0976a, S1000a also originated in the far side of Mars relative to the lander. The seismic energy from this event lasted up to 94 minutes, the longest ever recorded.
The Valles Marineris canyon system seen from the Viking Orbiter 1 Mars orbiter. Photo: NASA
According to Anna Horleston, the study’s lead author, both quakes occurred in an area known as the “core shadow zone,” where seismic waves cannot reach the InSight’s transducers directly because of the interference. bend or block as they pass through the planet’s core, instead they reflect at least once on the surface before being transmitted to the lander’s gauges.
“Recording events in the core shadow is a stepping stone to expanding our understanding of Mars. Prior to these two events, most earthquakes were within about 40 degrees of InSight.” co-author Savas Ceylan from the Swiss Federal Institute of Technology emphasized.
“S0976a and S1000a are not only the largest and most distant events of considerable amplitude, but also have a spectrum and duration unlike any previously observed. They are truly remarkable events. attention in the Martian seismic catalog,” added Horleston.
Doan Duong (According to Phys)
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