Scientists have received the latest information from the largest earthquakes

While NASA's Insight landing seismometer recorded the strongest earthquakes in recent months, Scientists have obtained new information about the structure of Mars by studying its data./p>

It was last year that the InSight probe recorded two earthquakes, one measuring 4.2 on the Richter scale and the other measuring 4.1 on the Richter scale. These pairs of earthquakes are the first recorded events on the far side of the planet from the landing site of this surface and are five times stronger than the largest previously recorded event.

• Probe NASA Insight Records largest earthquakes

Researchers at the Insight Earthquake Service (MQS) now report in an article on April 22, 2022 that data on seismic waves from these events could be Scientists help to understand the structure of Mars' inner layers, especially the boundary between the core and its mantle. Identify a Richter called S0976a and trace it to the Valles Marineris, a network of massive valleys that are one of the geological features of Mars and one of the largest graben systems in the solar system. Previous orbital images of cross faults and landslides show that the area is seismically active, but recent events are the first confirmed seismic activity there.

S1000a, a 4.1 magnitude event with 24 The next day it was recorded, with reflected PP and SS waves as well as P-diff waves, waves with a small amplitude that crossed the core-mantle boundary. This is the first time that P-diff waves have been observed in the Insight mission. Researchers have not been able to pinpoint the location of S1000a, but like S0976a, it originated in the other half of Mars, at 65 degrees in the center of the eastern end of the Mariner Valley. The S1000a seismic energy is also the longest-lasting seismic energy recorded on Mars, lasting 94 minutes.

Map of Martian ridges showing the position of the insite and two earthquakes.
Credit: Horelston et al. (2022) TSR

Both earthquakes occurred in the shadow region of the core, areas where the P and S waves do not reach the Insight seismometer directly due to being stopped or bent by the core. Thus, PP and SS waves do not follow a direct path, but are reflected at least once on the surface before moving toward the seismometer.

"Recording events in the nuclear shadow region is an effective step in increasing our understanding of Mars," Zurich said. Prior to these two events, most seismicity was detected at a distance of about 40 degrees from the insite. "But energy under the shadow of the Martian core passes through parts of Mars that we have never been able to sample seamlessly before."

Despite the similarities, the two earthquakes differ in several important ways. S0976a is characterized only by low frequency energy, like many other earthquakes ever detected on the planet. The S1000a, on the other hand, has a very wide frequency range. "The S1000a is a clear departure point in the list of recorded earthquakes and will be the key to our greater understanding of Martian seismology," Horleston said. He added: "Event S1000a has a very similar frequency spectrum to a family of events that we have modeled as shallow earthquakes and shells, so this event may have occurred near the surface. S0976a, on the other hand, is similar to many of the events we found in the Cerberus Fossae, a region with extensive faults modeled about 50 km or more deep, and this event probably has a similar mechanism, depth, and source. .

Two new earthquakes are considered real jets compared to the rest of the seismic activity identified by Insight. According to Horleston, these earthquakes are not only by far the largest and most distant events, but the S1000a has a completely different spectrum and duration than any previously observed event. So significant events are on the Martian seismic catalog.

Cover Photo: Graphic Design of Insight Surface
Credit: NASA/JPL-Caltech

Sources: Universe Today, SciTechDaily