The first-ever seismic signal to be measured on Mars has been reported by scientists monitoring NASA’s InSight mission. Researchers believe that the tiny “Marsquake” originated from within the planet rather than being the result of wind or other surface phenomena. Studying the seismology of Mars should provide important information about the interior of the planet and how it was formed.
The quake was detected on 6 April by a seismometer called SEIS, which InSight had placed on the Martian surface in December 2018. A weaker signal had been detected about three weeks earlier, but its origin is unclear. Signals with ambiguous origins were also measured on 10 and 11 April.
It’s so exciting to finally have proof that Mars is still seismically active
Philippe Lognonné
“We’ve been waiting months for a signal like this,” says Philippe Lognonné of the Institut de Physique du Globe de Paris in France – who leads the team that built SEIS. “It’s so exciting to finally have proof that Mars is still seismically active.”
Quieter than Earth
Mars is not the first place that scientists have detected extraterrestrial seismic activity. Five seismometers operated on the Moon between 1969 and 1977 and measured thousands of “moonquakes”. Like the Moon, Mars does not have tectonic plates and therefore is expected to be much quieter than Earth when it comes to seismic activity.
Scientists believe that seismic activity on Mars is related to the ongoing cooling of the interior of the planet, which is causing the planet to contract. This results in the build-up of stress, which is released by a break in the crust that generates a quake. A similar process is expected to occur on the Moon.
The long road to Mars
NASA’s director of planetary science Lori Glaze says that the 6 April signal is “exciting because its size and longer duration fit the profile of moonquakes detected on the lunar surface during the Apollo missions”.
Lognonné and colleagues are now analysing the four signals and expect to detect more in the future. “We’re looking forward to sharing detailed results once we’ve had a chance to analyse them,” he said.
Gaining insights into the interior of Mars is a primary goal of the InSight mission, which landed on the planet in November 2018 and is expected to operate for at least two years.
The above video from NASA is an audio and video illustration of the signal, which has been sped-up by a factor of 60 and amplified greatly in order to be audible.
