New study: Earth has earthquakes; Mars has ‘marsquakes’
In a new study released today in Nature Geoscience, NASA’s InSight scientific mission team is reporting the first evidence of seismic activity on the planet Mars, recorded by the lander known as InSight. When seismic activity occurs here on Earth, scientists call them ‘earthquakes.’ Likewise, scientists in the new paper have coined the phrase ‘marsquakes.’
Among the team of 100 scientists from around the world who have taken a first look at the seismic data is Scott King, a professor in the Department of Geosciences, and Josh Murphy, a doctoral student working with King. According to the paper, from April 2019 to October 2019, more than 150 marsquakes were recorded by InSight’s seismometer, indicating that Mars is a seismically active planet.
“This is an important result because we now know that planets like Mars, that doesn’t have plate tectonics, also experience seismic activity,” said King, who is using computer models of Mars’ interior core to test the data collected by InSight. His research, so far, indicates the quakes are caused by a large section of solid rock, known as plumes, moving from hot regions deep within the planet upwards toward the surface.
How intense are the marsquakes? Thus far, the largest event equals a roughly magnitude 4 earthquake, although there is an apples-oranges variation due to the seismic event’s origins. “We are still waiting and hoping for a much bigger quake,” King said. “The bigger the quake the more energy would travel deep through the planet and we could nail the exact location of the core.”
InSight – that’s short for Interior Exploration using Seismic Investigations, Geodesy and Heat Transport, NASA loves its acronyms -- touched down on the Elysium Planitia of Mars in November 2018 after a 301-million-mile journey. Its mission: to study the deep interior of the planet. It sports three primary instruments: a pair of seismometers, a device designed to monitor heat-flow and other physical properties, and rotation/interior apparatus designed to provide exact measurement of Mars’ rotation and wobble.”
The initial announcement of marsquakes was by NASA made in April 2019. This paper represents the first full report delving into the causes and number of occurrences of the seismic events, King said.
The possibility of seismic events on Mars has been debated among scientists since the 1970s, King said. In 1976, the Viking landers that were first to arrive on Mars had seismometers but they were not placed directly on or into the planet’s surface. Strong winds on Mars -- in the range of 10-20 miles per hour – caused a great deal of shaking to the lander, making tracking seismic events impossible. InSight’s seismometer sits on the ground and has wind protection built into it, hence the new, much better data.
Using high-performance computing clusters based at Virginia Tech’s Advanced Research Computing facilities, the models are predicting how the high topography southern hemisphere of Mars controls the heat within the red planet, King added. One question to solve: Do pockets of molten rock exist many kilometers deep below the surface of Mars, and if so where? “Molten rock has a distinctive signature on seismic recordings so these models will be tested as we gather more data,” King added.