Posted on 12/19/2020 5:13:03 PM PST by BenLurkin
InSight's seismometer... is sensitive enough to detect slight rumblings from great distances. But it wasn't until April 2019 that seismologists with the Marsquake Service, coordinated by ETH Zurich, detected their first marsquake. Since then, Mars has more than made up for lost time by shaking frequently, albeit gently, with no quakes larger than magnitude 3.7.
The lack of quakes larger than magnitude 4 poses something of a mystery, considering how frequently the Red Planet shakes due to smaller quakes.
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Once InSight started detecting quakes, they became so regular that, at one point, they were happening every day. Then, in late June of this year, the detections essentially stopped. Only five quakes have been detected since then, all of them since September.
Scientists believe Mars' wind is responsible for these seismically blank periods: The planet entered the windiest season of the Martian year around June. The mission knew that winds could affect InSight's sensitive seismometer, which is equipped with a domed wind and heat shield. But the wind still shakes the ground itself and creates literal noise that covers up quakes. settling down.
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All quakes have two sets of body waves, which are waves that travel through the planet's interior: primary waves (P-waves) and secondary waves (S-waves). They also ripple along the top of the crust as part of a third category, called surface waves.
On Earth, seismologists use surface waves to learn more about the planet's internal structure. Before getting to Mars, InSight's seismologists expected these waves to offer glimpses as deep as 250 miles (about 400 kilometers) below the surface, into a sub-crustal layer called the mantle. But Mars continues to offer mysteries: Despite hundreds of quakes, none has included surface waves.
(Excerpt) Read more at phys.org ...
Could this have something to do with:
Mars Mass 1.415 × 10²⁴ lbs
Earth Mass 1.317 × 10²⁵ lbs
(i.e. Earth 10 times the mass of Mars)
A few more probes like this would solve the mystery. You can guess distance with one eye but 2 eyes gives you a better idea of how far away something is.
I don’t think there’s been any visible signs of volcano activity on mars.
Is the core solid?
The lack of an inner core would explain the lack of a magnetic field and how the solar wind could take away all the water.
I’m not a geologist, but I thought the latest theory about why Mars’ atmosphere is so thin was because, unlike Earth, it has no magnetosphere to protect it from the solar winds, so the atmosphere gets stripped off. And I thought the reason for this lack of a magnetosphere was because Mars no longer has a molten iron core. No iron core, no continental drift, so no earthquakes. I would appreciate any information to correct my assumptions.
“Is the core solid?”
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I don’t believe so. However, I do believe the Crust and mantle to be thicker due to distance from the sun (much cooler).
Earth 150 million km
Mars 228 million km
Quakes are mostly caused by blasting operation as they build new or extend old tunnels and make new cities. Martians live underground you know.
As the molten core cools down the magnetosphere weakens. When that happens your atmosphere begins to dissipate.
That was my understanding of things, but I mistakenly thought you also needed a molten core (and plate tectonics) to have earthquakes. I thought the interior of Mars was cool, so no magnetosphere and no marsquakes. I have since learned the following:
"But that activity is quite different from what we're used to on Earth, where most quakes are caused by tectonic plates sliding against, over or under each other. Mars doesn't have active plate tectonics, the researchers said, so both types of quakes are caused by the long-term cooling of the planet since its formation 4.5 billion years ago." Space.com
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