Yes, there are quakes on Mars too!
Recently, NASA’s InSight lander stationed on the red planet Mars has detected two massive scale seismic tremors there. They are known as marsquakes. The first one named S0976a took place on 25th August 2021 and was of the magnitude 4.2. This originated in the vast canyon region on Mars called Valles Marineris, that is spread across 2500 miles. The second quake was called S1000a and occurred 24 days later and was of 4.1 magnitude. Although its exact location is still unknown, it is now being regarded as the longest seismic event on Mars that lasted for 94 minutes. In context of these recent seismic occurrences on the red planet, let us understand what marsquake means and how it is measured.
Marsquake: What does it mean?
To put it simply, marsquake refers to a seismic tremor or a quake on Mars that is the equivalent of an earthquake and proves that the red planet is seismically active. Unlike Earth, Mars doesn’t have tectonic plates and hence can’t produce catastrophic quakes (due to collision of the plates) like the ones we experience on Earth. Instead, tremors on the red planet are caused by faults or fractures in its crust. These faults and fractures are in turn caused by meteorites, land tides, volcanic eruptions, or magma (molten matter within the planet’s surface) trying emanate from beneath the surface. However, until 6th April 2019 (when the InSight lander first detected a faint seismic signal), scientists were unable to measure Martian seismic tremors.
How are marsquakes measured?
On November 2018, six months before the first marsquake was detected, NASA’s robotic InSight lander had touched down on the Martian surface. It carried with it an instrument called Seismic Experiment for Interior Structure (or SEIS) that was designed and developed by the French Space Agency, CNES.
Just like seismometers (instrument used to detect and measure earthquakes) are fitted in underground vaults on earth, away from temperature and climate changes, SEIS was sealed beneath the Martian surface with the help of several insulating barriers such as Wind and Thermal Shield to save the instrument from the red planet’s more extreme conditions.
Since then, whenever the SEIS detects a tremor, it sends the data to the Jet Propulsion Laboratory in California where the seismologists measure its magnitude.