The earthquake came quickly and powerfully. Currently, NASA’s Insight mission can detect two earthquakes a day at a landing site near the Martian equator, and the frequency of earthquakes is rising. “There are really many earthquakes. Bruce Banerdt, a geophysicist at the Jet Propulsion Laboratory in Pasadena, California, and lead researcher on the Insight project, said. He recently presented the findings at a meeting of the American Geophysical Union in San Francisco, California.
Since arriving on Mars a year ago, Insight has detected 322 earthquakes on Mars. It was the first earthquake to be detected outside Earth and the moon, which scientists hope will explore the interior of Mars, including declassifying the interior structure of the Martian crust, mantle and core.
Most Martian earthquakes are small and much smaller than any one can be felt on Earth. But there are also a few that are big enough to reach level 4, so that scientists can track their origin.
Of these, the two largest earthquakes occurred in the geologically active area of the Kobelos trench, 1,600 kilometers east of Insight. The earthquake there may be the result of a cumulative release of stress from The Martian crustal faults.
Insight has achieved much since it arrived on Mars, but one of its main goals — to send a thermal probe five meters deep into the surface of Mars — is still out of reach. The detector, known as the Mole, encountered more friction in the soil than scientists had expected. Last October, it even unexpectedly “jumped out” of the hole.
The reason is that the soil envisioned by the engineer for this task is different from the actual situation. The Mole is designed for non-sticky soil, where there is little friction between particles, as in a large bucket of sugar. But Tilman Spohn, a space scientist at the German Aerospace Center, said the soil attached to the Insight landing site proved to be sticky, more like a bucket of batter. As a result, when the Mole began digging, the surrounding soil was crushed into a pit, and the detector was unable to keep moving underground.
So far, Insight’s biggest discovery has come from an ever-expanding record of Martian earthquakes. There are usually two types of earthquakes on Mars. The most common is high-frequency vibration. Less common is a type of earthquake that can be detected at lower frequencies. Domenico Giardini, a seismologist at the Swiss Federal Institute of Technology, said high-frequency signals could come from earthquakes that destroy The shallow crust of Mars, while low-frequency signals could come from deep in the mantle inside Mars.
In May and July, Mars experienced two of the largest earthquakes, both of which were low frequency types. The researchers tracked the seismic energy and found it originated in the Coperlos trench. This area is the birthplace of recent geological activity on Mars, and these faults appear to have moved over the past 10 million years.
Prior to the launch, researchers had predicted that it could detect earthquakes from the Kobelos trench. Alice Jacob, a planetary scientist at the Institute of Geophysics in Paris, France, says faults there may build up pressure at its end. An analysis led by her suggests that this may be the source of the Mars earthquake discovered by Insight.
Banerdt said the frequency of earthquakes on Mars has been increasing, from several sporadic earthquakes reported after the Insight landing to two times a day to the present, but mission scientists aren’t sure what’s behind it.