The first marsquake detected indicates the shallow subsurface of Mars contains far less water than Earth - but Mars is no where near as dry as the Moon.
"We've been collecting background noise up until now, but this first event officially kicks off a new field: Martian seismology!" said InSight Principal Investigator Bruce Banerdt. This is expected to be the first of multiple marsquakes detected by the SEIS instrument. InSight, which landed on Mars in November a year ago, is a mission specifically created to study the guts of Mars.
The American space agency's InSight robotic probe picked up the faint rumble on Mars on April 6, the lander's 128th Martian day, or sol.
A Nasa probe has detected and measured what scientists believe to be a "marsquake", marking the first time a likely seismological tremor has been recorded on another planet, the Jet Propulsion Laboratory in California.
The seismic quake was so small it wouldn't have registered on Earth's surface, but because the Martian surface is so still, the instrument's sensor was able to detect the slight tremor.
This quake is similar to the ones measured on the moon during the Apollo missions. The two experimental satellites not only relayed the good news in nearly real time, they sent back InSight's first snapshot of Mars just 4½ minutes after landing. Detected by SEIS' more sensitive Very Broad Band sensors, these signals were even smaller than the Sol 128 event and more ambiguous in origin.
Unlike Earth, Mars and the moon lack tectonic plates, so their quakes are caused by faults, or fractures, in their crusts.
The weak nature of this seismic event means NASA didn't get any "solid data" on the planet's interior, according to NASA.
"It's so exciting to finally have proof that Mars is still seismically active", Philippe Lognonne, a geophysicist at the Institut de Physique du Globe de Paris in France, said in a statement. Though scientists don't know exactly what caused it, they think it was a marsquake, and not a disturbance caused by wind or other environmental conditions.
InSight's Seismometer on the Martian Surface: This image shows InSight's domed Wind and Thermal Shield, which covers its seismometer.
InSight's measurements of significant seismological activity will help with the lander's primary mission to study the interior of Mars. Their seismic activity is instead driven by a cooling and contracting process that causes stress to build up and become strong enough to rupture the crust. "We're looking forward to sharing detailed results once we've had a chance to analyse them".