Mercury Is Tectonically Alive and Kicking: Quakes Still Occur On The ‘Shrinking’ Planet

Mercury may share a certain trait with Earth; it seems that the former is still geologically active. A new study based on images collected by NASA's MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission reportedly found that Mercury may be the only other planet in the solar system to experience earthquakes, or rather mercuryquakes.

The MESSENGER probe was launched in 2004 and orbited the closest planet to the sun for four years from 2011 to 2015, after which an engineered crash saw the craft hitting Mercury's surface in April last year. Over the past years, scientists have been studying the data gathered by the spacecraft to get more insight into the planet which has always been somewhat of a mystery to us.

During their detailed study, researchers discovered an unknown facet about Mercury's surface - the presence of small formations called scarps. Scarps are formed when the pressure along fault lines pushes rocks together and thrusts them upwards. The Mariner 10 probe took, which took place 40 years ago, had first photographed scarps on the planet. However, the ancient cliff like formations, laden with craters, indicated that the planet was geologically dead for millions of years.

However, the photos sent by MESSENGER show scarps that are smaller, and untouched by asteroid impact, suggesting that they are geologically younger, and are less than 50 million years old. The recent findings imply that Mercury's subsurface is still geologically active.  In addition, the presence of scarps also means that Mercury is gradually shrinking while it cools, and the shrinkage has been quite extreme in the past billion years, which also increases the potential for quakes.

"This is why we explore," said Jim Green, Planetary Science Director at NASA. "For years, scientists believed that Mercury's tectonic activity was in the distant past. It's exciting to consider that this small planet - not much larger than Earth's moon - is active even today."