Mars surface
Mysterious rumblings known as 'Marsquakes' have been detected by Nasa's InSight lander, offering further clues about volcanic activity beneath the surface of the Red Planet.

The tremors originated in a region called Cerberus Fossae - an area where Nasa scientists have picked up significant seismical activity and even landslides in the past.

They believe the tremors were likely caused by a sudden release of energy beneath the surface of the planet, but as Mars doesn't have tectonic plates like Earth, the precise cause and origins of the rumblings remain unknown.

The quakes were picked up by InSight's seismometer, an onboard device specially built to capture Marsquakes.

Using its robotic arm, InSight has partially buried the seismometer to protect it from strong seasonal winds and allow for more accurate readings.

The area here the quakes were detected - Cerberus Fossae - is a steep-sided area cut into volcanic plains where active landslides were photographed in 2019.

Intriguingly, the quakes occurred almost exactly one Martian year - or two Earth years - after two previous quakes were detected in the same area.

InSight has recorded over 500 quakes to date, but because of their clear signals, these four were the best quake records for probing the interior of the planet, Nasa said in a statement announcing the quakes.

Taichi Kawamura of France's Institut de Physique du Globe de Paris, which provides support to the Nasa mission, said the quakes added to scientists understanding of volcanic activity on the planet.

'Over the course of the mission, we've seen two different types of Marsquakes: one that is more 'Moon-like' and the other, more 'Earth-like,' he said.

Earthquake waves travel more directly through the planet, while those of moonquakes tend to be very scattered, said Kawamura.

Marsquakes fall somewhere in between.

'Interestingly all four of these larger quakes, which come from Cerberus Fossae, are 'Earth-like.'

InSight launched from Vandenberg Air Force Base in California in May 2018, touching down on Mars in November that year with the mission of giving the planet its first thorough check-up since it formed 4.5 billion years ago.

It is working in conjunction with several missions orbiting Mars and roving around on the planet's surface: including the Curiosity rover.

InSight's ability to adapt to the incredibly harsh conditions on the planet has given in an effort to gain more accurate data.

It regularly faces extreme swings in temperature - from minus 148 Fahrenheit during the night to 32 Fahrenheit - and fierce seasonal winds.

Its hoped that the Martian summer will bring calmer weather, making it easier to detect other quakes.

In order to record more accurate data, the InSight lander has begun using a scoop on its robotic arm to place soil over the cable connecting its seismometer - called the Seismic Experiment for Interior Structure (SEIS) - to the spacecraft.

'That allows the soil to get as close to the shield as possible without interfering with the shield's seal with the ground.'

Scientists hope insulating it from the wind will make it easier to detect Marsquakes.

The new quakes were slightly smaller than two previous quakes of magnitude 3.6 and 3.5 detected n the same region.

InSight has recorded over 500 quakes to date, but because of their clear signals, these are four of the best quake records for probing the interior of the planet.