<p>In addition to @Erik answer, rocks as any other material dilates when it gets hotter and contracts as it gets colder. On Earth's such phenomena, and differences in temperature within rocks  leads even to the cracking of rocks.</p>

<p>That could be another source of microseismicity, because the thermal amplitude in Mars is huge. The temperatures on the two Viking landers, <a href="http://www.astronomycafe.net/FAQs/q2681x.html" rel="nofollow noreferrer">measured at 1.5 meters above the surface ranged from -17.2°C to -107°C</a>.</p>

<p>Another one could be meteorite and micrometeorites impacts, that could be more common there due to the much thinner atmosphere.</p>

<p>Finally, Mars interior is getting colder, therefore its inner layers are contracting and its diameter slowly shrinking. That leads to <a href="https://en.wikipedia.org/wiki/Thrust_fault" rel="nofollow noreferrer">thrust faults</a>, that have been observed in other solar system bodies (specially smaller moons and <a href="https://www.nasa.gov/mission_pages/LRO/news/shrinking-moon.html" rel="nofollow noreferrer">even our Moon</a>). This thrusting also can cause seismicity and microiseismicity without any doubt.</p>

CC BY-SA 4.0
2019-03-19T22:54:21.137Z
okay now we're cooking... without need for water. thanks
uhoh
CC BY-SA 4.0
2019-03-20T06:18:42.717Z
even if mars have no liquid water it still experience some tidal forces and this might create small quakes i think.
trond hansen
CC BY-SA 4.0
2019-03-19T18:33:04.113Z
2019-03-19T23:01:02.573Z
2019-03-19T23:01:02.573Z
Camilo Rada
<p>I think that the mechanism suggested in the article fits the bill the best:</p>

<blockquote>
  <p>On Earth, microseisms are ubiquitous, caused largely by the sloshing
  of the ocean by storms and tides. Mars, despite the dreams of science
  fiction writers, has no present-day oceans. Instead, <strong>this newly
  discovered noise is likely caused by low-frequency pressure waves from
  atmospheric winds that rattle the surface, inducing shallow,
  longer-period waves in the surface, called Rayleigh waves</strong>, Lognonné
  said.</p>
</blockquote>

<p>See e.g., <a href="https://www.lpi.usra.edu/meetings/lpsc2012/pdf/1994.pdf" rel="noreferrer">https://www.lpi.usra.edu/meetings/lpsc2012/pdf/1994.pdf</a> , for a modeling study of the microseismic events on Mars due to wind. </p>

CC BY-SA 4.0
2019-03-19T14:19:18.280Z
That's an interesting conference paper; there's quite a lot of vocabulary I don't understand; I'll try to do some reading and may need to post further questions. *Thanks!*
uhoh
CC BY-SA 4.0
2019-03-19T14:07:34.110Z
2019-03-19T14:07:34.110Z
Erik
<p>The anouncement published in Science <a href="https://www.sciencemag.org/news/2019/03/mini-tremors-detected-mars-first-time" rel="noreferrer">Mini tremors detected on Mars for first time</a> says that the Mars lander InSight is detecting <a href="https://en.wikipedia.org/wiki/Microseism" rel="noreferrer">microseisms</a> on Mars after various vibrations produced by the lander and its interaction with the wind are excluded.</p>

<p>The above linked Wikipedia article says:</p>

<blockquote>
  <p>In seismology, a microseism is defined as a faint earth tremor caused by natural phenomena. Sometimes referred to as a "hum", it should not be confused with the anomalous acoustic phenomenon of the same name. The term is most commonly used to refer to the dominant background seismic and electromagnetic noise signals on Earth, <strong>which are caused by water waves in the oceans and lakes.</strong> Characteristics of microseism are discussed by Bhatt. Because the ocean wave oscillations are statistically homogenous over several hours, the microseism signal is a long-continuing oscillation of the ground. The most energetic seismic waves that make up the microseismic field are Rayleigh waves, but Love waves can make up a significant fraction of the wave field, and body waves are also easily detected with arrays. Because the conversion from the ocean waves to the seismic waves is very weak, the amplitude of ground motions associated to microseisms does not generally exceed 10 micrometers. (several citations available in original article)</p>
</blockquote>

<p>We can exclude large surface bodies of water on Mars, so the vibrations must be coming from other sources.</p>

<p><strong>Question:</strong> What could be causing microseisms on Mars?</p>

CC BY-SA 4.0
2019-03-19T06:49:39.473Z
do you have any information about the time of day this happens,or is it the same night and day i think this might limit the possibilities for the origin of the quakes.
trond hansen
CC BY-SA 4.0
2019-03-19T06:51:48.100Z
@trondhansen I'm open to any mechanisms that "could be causing microseisms on Mars" they wouldn't have to be the source of any particular measured events.
uhoh
<mars><microseism>
What could be causing microseisms on Mars?
uhoh
# What could be causing microseisms on Mars?

(Asked by: username_0 on 2019-03-19)

The anouncement published in Science [Mini tremors detected on Mars for first time](https://www.sciencemag.org/news/2019/03/mini-tremors-detected-mars-first-time) says that the Mars lander InSight is detecting [microseisms](https://en.wikipedia.org/wiki/Microseism) on Mars after various vibrations produced by the lander and its interaction with the wind are excluded.

The above linked Wikipedia article says:

> In seismology, a microseism is defined as a faint earth tremor caused by natural phenomena. Sometimes referred to as a "hum", it should not be confused with the anomalous acoustic phenomenon of the same name. The term is most commonly used to refer to the dominant background seismic and electromagnetic noise signals on Earth, **which are caused by water waves in the oceans and lakes.** Characteristics of microseism are discussed by Bhatt. Because the ocean wave oscillations are statistically homogenous over several hours, the microseism signal is a long-continuing oscillation of the ground. The most energetic seismic waves that make up the microseismic field are Rayleigh waves, but Love waves can make up a significant fraction of the wave field, and body waves are also easily detected with arrays. Because the conversion from the ocean waves to the seismic waves is very weak, the amplitude of ground motions associated to microseisms does not generally exceed 10 micrometers. (several citations available in original article)

We can exclude large surface bodies of water on Mars, so the vibrations must be coming from other sources.

**Question:** What could be causing microseisms on Mars?

**Tags:** mars, microseism

> **Comments:**
> **username_1**: do you have any information about the time of day this happens,or is it the same night and day i think this might limit the possibilities for the origin of the quakes.  
> **username_0**: @username_1 I'm open to any mechanisms that "could be causing microseisms on Mars" they wouldn't have to be the source of any particular measured events.  

---

## 2 answers

### Answer by username_2 on 2019-03-19. Score: 4 | Accepted answer

In addition to @username_3 answer, rocks as any other material dilates when it gets hotter and contracts as it gets colder. On Earth's such phenomena, and differences in temperature within rocks leads even to the cracking of rocks.

That could be another source of microseismicity, because the thermal amplitude in Mars is huge. The temperatures on the two Viking landers, [measured at 1.5 meters above the surface ranged from -17.2°C to -107°C](http://www.astronomycafe.net/FAQs/q2681x.html).

Another one could be meteorite and micrometeorites impacts, that could be more common there due to the much thinner atmosphere.

Finally, Mars interior is getting colder, therefore its inner layers are contracting and its diameter slowly shrinking. That leads to [thrust faults](https://en.wikipedia.org/wiki/Thrust_fault), that have been observed in other solar system bodies (specially smaller moons and [even our Moon](https://www.nasa.gov/mission_pages/LRO/news/shrinking-moon.html)). This thrusting also can cause seismicity and microiseismicity without any doubt.

> **Comments:**
> **username_0**: okay now we're cooking... without need for water. thanks  
> **username_1**: even if mars have no liquid water it still experience some tidal forces and this might create small quakes i think.  

---

### Answer by username_3 on 2019-03-19. Score: 6

I think that the mechanism suggested in the article fits the bill the best:

> On Earth, microseisms are ubiquitous, caused largely by the sloshing
> of the ocean by storms and tides. Mars, despite the dreams of science
> fiction writers, has no present-day oceans. Instead, **this newly
> discovered noise is likely caused by low-frequency pressure waves from
> atmospheric winds that rattle the surface, inducing shallow,
> longer-period waves in the surface, called Rayleigh waves**, Lognonné
> said.

See e.g., <https://www.lpi.usra.edu/meetings/lpsc2012/pdf/1994.pdf> , for a modeling study of the microseismic events on Mars due to wind.

> **Comments:**
> **username_0**: That's an interesting conference paper; there's quite a lot of vocabulary I don't understand; I'll try to do some reading and may need to post further questions. *Thanks!*  

---

