Last May, the Mars Insight lander measured the strongest marsquake ever recorded at magnitude 4.7. That doesn’t seem like much. Many states in the US, especially along the west coast and Alaska, have recorded much stronger earthquakes. Even here in Oklahoma, we've had quakes within the past few years above stronger than that. Most Oklahoma quakes are linked to fracking operations. On Mars, they occur from slippage at buried faults.
An international team of
researchers led by Taichi Kawamura at the Institut de physique du globe de
Paris, France published a recent analysis of the May quake. In the paper, he stated,
“The [May 4, 2022 quake] was definitely the biggest marsquake that we have seen.”
The data allowed scientists to
learn details about the Martian interior that was unknown before that quake.
For example, the shaking lasted for ten hours. The previous record holder only
shook the ground for an hour.
One of the study’s co-author,
seismologist John Clinton at the Swiss Seismological Service, ETH Zurich, said
“The energy released by this single marsquake is equivalent to the cumulative
energy from all other marsquakes we’ve seen so far. And although the event was
over 2,000 kilometers (1,200 miles) distant, the waves recorded at InSight were
so large they almost saturated our seismometer. For the first time, we were
able to identify surface waves, moving along the crust and upper mantle, that
have traveled around the planet multiple times.”
The kicker is that until Insight began measuring these quakes on Mars, scientists believed that the Red Planet was geologically dead. Earth is almost twice the size of Mars and scientists assumed that the Martian core had cooled so that no geologic activity could occur. Geologic activity implies molten magma below the surface, and that heat could keep any subsurface water liquid.
Mars once had oceans, lakes, and
rivers. When its magnetic field collapsed, supposedly due to the core
solidifying, the Martian atmosphere was blasted into space by solar radiation.
On Earth, that radiation is blocked by our magnetic field. Once the air thinned
out, the water evaporated and was blasted into space with the atmosphere, or
froze underground. At least that was the traditional scientific belief.
This large quake adds strong proof
that Mars is still quite active, something few scientists believed prior to InSight
with its seismometer. As Kawamura said, “Stay tuned for more exciting stuff
following this.”
Who knows what other surprises
await us from Mars? Unfortunately, the InSight lander has made its final discovery.
Martian dust has covered its solar cells to the point that it has no more power.
“We are impressed that almost at the end of the extended mission, we had this
very remarkable event,” Kawamura said. Based on the data gathered from this
quake, “I would say this mission was an extraordinary success.”
Each month, I write an astronomy-related column piece for the Oklahoman newspaper. After it is published there, I post that same column to my blog page.
This is reprinted with permission from the Oklahoman and www.Oklahoman.com.
