<p>I have read the question <a href="https://earthscience.stackexchange.com/questions/218/what-generates-the-microseism">What generates the microseism?</a> and it's accompanying answer.</p>

<p>In [#1, cited below], they use the azimuth values of seismographic activity on the flanks of the volcano Stromboli to discern where this microseismic "noise" is coming from:</p>

<blockquote>
  <p>The behaviour of polarisation at the east flank lets us suppose
  that the microseismic noise comes from this direction.
  This is the direction of the Scirocco wind (south, southeast
  direction) that blows on Stromboli during summer season.</p>
</blockquote>

<p>So, according the other answer on the site, these low frequency oscillations are due to the wind's effect on the waves of the ocean.  In the initial question that sparked the answer, it was cited the frequency of these ocean waves was 0.2 Hz, which is in the 0.1-0.5 Hz region that the Stromboli researchers were looking at.</p>

<p>The whole crux of the Stromboli paper was that the microseismic events (volcanic and non-volcanic) were enough to confound the separation of the tremor signals into independent components  These researchers were using independent component analysis (ICA) and were able to pull a 0.2 Hz and a 0.4 Hz component out of the mixture (likely corresponding to the 0.2 Hz ocean wave energy mentioned in the other question). </p>

<p><img src="https://i.sstatic.net/NMaAz.png" alt="enter image description here"> </p>

<p>The remaining energy in the microseismic range (which can be seen in the first two components) is preventing further separation of the other components of the microseismic activity .</p>

<p>Stromboli has a constant tremor due to its ongoing activity, but have there been efforts elsewhere to suss out which of the microseismic activities are from sources in the ocean versus those coming from intermittent volcanic tremors?  Could this be achieved by using a combination of sensors, some in the ocean and some on land, or is this type of analysis not really useful?</p>

<blockquote>
  <p>Reference:</p>
  
  <ol>
  <li>De Lauro, E,De Martino, S, Falanga, M, and Palo, M. (2006). Statistical analysis of Stromboli VLP tremor in the band [0.1-0.5]Hz: some consequences for vibrating structures. <em>Nonlin. Processes Geophys., 13</em>, 393–400. <a href="http://dx.doi.org/10.5194/npg-13-393-2006" rel="nofollow noreferrer">[DOI]</a> <a href="http://www.nonlin-processes-geophys.net/13/393/2006/npg-13-393-2006.pdf" rel="nofollow noreferrer">[PDF]</a> (freely available)</li>
  </ol>
</blockquote>

<geophysics><ocean><seismology><volcanology><ocean-currents>
What efforts have been made to separate the microseismic events related to wind-related ocean waves from the components of volcanic origin?
jonsca
# What efforts have been made to separate the microseismic events related to wind-related ocean waves from the components of volcanic origin?

(Asked by: username_0 on 2014-09-15)

I have read the question [What generates the microseism?](https://earthscience.stackexchange.com/questions/218/what-generates-the-microseism) and it's accompanying answer.

In [#1, cited below], they use the azimuth values of seismographic activity on the flanks of the volcano Stromboli to discern where this microseismic "noise" is coming from:

> The behaviour of polarisation at the east flank lets us suppose
> that the microseismic noise comes from this direction.
> This is the direction of the Scirocco wind (south, southeast
> direction) that blows on Stromboli during summer season.

So, according the other answer on the site, these low frequency oscillations are due to the wind's effect on the waves of the ocean. In the initial question that sparked the answer, it was cited the frequency of these ocean waves was 0.2 Hz, which is in the 0.1-0.5 Hz region that the Stromboli researchers were looking at.

The whole crux of the Stromboli paper was that the microseismic events (volcanic and non-volcanic) were enough to confound the separation of the tremor signals into independent components These researchers were using independent component analysis (ICA) and were able to pull a 0.2 Hz and a 0.4 Hz component out of the mixture (likely corresponding to the 0.2 Hz ocean wave energy mentioned in the other question).

![enter image description here](https://i.sstatic.net/NMaAz.png)

The remaining energy in the microseismic range (which can be seen in the first two components) is preventing further separation of the other components of the microseismic activity .

Stromboli has a constant tremor due to its ongoing activity, but have there been efforts elsewhere to suss out which of the microseismic activities are from sources in the ocean versus those coming from intermittent volcanic tremors? Could this be achieved by using a combination of sensors, some in the ocean and some on land, or is this type of analysis not really useful?

> Reference:
>
> 1. De Lauro, E,De Martino, S, Falanga, M, and Palo, M. (2006). Statistical analysis of Stromboli VLP tremor in the band [0.1-0.5]Hz: some consequences for vibrating structures. *Nonlin. Processes Geophys., 13*, 393–400. [[DOI]](http://dx.doi.org/10.5194/npg-13-393-2006) [[PDF]](http://www.nonlin-processes-geophys.net/13/393/2006/npg-13-393-2006.pdf) (freely available)

**Tags:** geophysics, ocean, seismology, volcanology, ocean-currents


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## 0 answers

