The earthquake also lasted a very long time. About an hour and a half!
Last weekend, Marslander InSight celebrated its 1,000th day on Mars. The feast was accompanied by a special reveal. InSight recorded one of the largest earthquakes on Mars. The quake had a magnitude of 4.2 and — for an hour and a half — also entered the books as the longest quake detected by InSight to date.
It would be very close if InSight missed this big earthquake. Because it was originally intended that all of the lander’s scientific instruments – including the seismometers – would be off for a few months. A necessary evil, because Mars revolves around the sun in an elliptical orbit and accelerates toward the apogee (the point in the orbit furthest from the sun). In the period around the peak, less sunlight hits the already dusty InSight solar panels. To prevent the lander from suffering from a power shortage and being unable to keep critical parts – such as the onboard computers and heaters – running, all less critical energy consumers are planned to be shut down for several months around June.
But then the InSight team came up with a very innovative way to clean some of the dust from the solar panels and thereby increase the energy yield. On a windy day, the InSight robotic arm is allowed to scrape off the sand and then the grains of sand fall back onto the solar panels. It is hoped that at least some of the sand – with the help of the wind – will bounce off the solar panels and pick up some dust particles, before the wind carries it away again. The approach worked. And thanks to the slightly clean solar panels, there’s also enough energy available at greater distances from the sun to keep the seismometers running.
Three big orgasms
It paid off. Because the main earthquake observed by seismometers this weekend was already the third major earthquake InSight has recorded in a month. In late August, two earthquakes measuring 4.2 and 4.1 were recorded in one day.
The strongest earthquake recorded by Insight before August 2021 was a magnitude 3.7. This earthquake was detected in 2019. For comparison, a magnitude 4.2 earthquake has five times more energy than a magnitude 3.7 earthquake.
Earthquakes on Mars are of great value to scientists. Earthquakes produce seismic waves that change as they travel through Mars’ crust, mantle, and core. By studying the waves and the changes they undergo, researchers can gain more insight into the formation of Mars.
The last major earthquake – which occurred at the end of last week – has not been analyzed. But late August vibrations have been investigated. Research shows that a magnitude 4.2 earthquake occurred at a distance of at least 8,500 kilometers from Insight. This makes it the farthest earthquake InSight has detected so far. The source of the earthquake is still unclear. What is certain is that it could not have come from the place where most of the earthquakes detected by InSight are generated: Cerberus Fossae, an area about 1,600 kilometers from InSight. An interesting possibility is that the quake InSight recorded in late August came from Valles Marineris – a large fault system on Mars. The heart of this valley system lies about 9,700 kilometers from InSight.
do not agree
What the researchers also noticed was that the two earthquakes detected in late August were very different from each other. For example, a magnitude 4.2 earthquake is characterized by slow tremors of low frequency, while another quake, originating about 925 km from Insight, experienced rapid, high-frequency tremors. The difference is music to the ears of the scholars. Recording vibrations coming from different distances from InSight and generating different types of seismic waves is invaluable for research on the structure of Mars.
Meanwhile, the distance between Mars and the Sun is shrinking again, and the power that InSight can generate using its solar panels is steadily increasing. But a new challenge awaits him: the Martian conjunction. Mars and Earth are on opposite sides of the Sun. Since solar radiation can affect radio signals, there is no temporary connection between Earth and Mars. The final order will be sent to InSight at the end of this month. Even though the radio is silent, the seismometer continues to look for vibrations.
… have InSight drills where it can also conduct research deep into the Martian surface? With the help of this exercise, NASA wants to measure the temperature about five meters below the Martian surface, thereby gaining more insight into the amount of heat still emanating from the interior of Mars. However, this part of InSight’s mission failed. Earlier this year, NASA gave up; Deep digging turned out to be very difficult.