<div dir="ltr">Hi Illias, <div><br><div>This is really an exciting event! </div></div><div><br></div><div>From the video, it is clear that the volcano induced lot of deformation at the surface and some faulting. So, even if it is not active anymore, you may be able to monitor the re-compaction of the site in the near surface and maybe extending deeper. </div><div><br></div><div>If you want to monitor what's happening down to the reservoir, it's more tricky. You would need low frequencies (down to 0.1 Hz maybe) but these frequencies mean long wavelength so poor spatial resolution. Given the volume of mud erupted, the reservoir it's coming from might be quite small (maybe few tens of meters thick), so it's not clear to me if one can see changes at these depths using surface waves. </div><div><br></div><div>On the other hand, there might be some micro-seismicity down there that you can record and locate with a surface network that would be helpful to delineate the depth extent of the activity/reservoir.</div><div><br></div><div>Anyway, I would deploy the sensors as soon as possible. Maybe one station really close to the volcano (<100m), two/three others at ~500m /1km and the two last at 3-5 km from the vent. See my tentative of a design attached (plus the .kmz file).</div><div><br></div><div><img src="cid:161a5f73617608c859d1" alt="Devil’s Woodyard mud volcano_seismicarray.jpg" class="" style="max-width: 100%; opacity: 1;"><br></div><div><br></div><div>To give you an idea of what can be done with ambient noise and about the seismicity on a (much bigger) mud volcano at Lusi in Indonesia, see the papers attached. </div><div><br></div><div>Cheers, </div><div><br></div><div>Aurelien</div><br><div class="gmail_quote"><div dir="ltr">Le sam. 17 févr. 2018 à 11:50, Thomas Lecocq <<a href="mailto:thomas.lecocq@seismology.be" target="_blank">thomas.lecocq@seismology.be</a>> a écrit :<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi Ilias,<br>
<br>
Wooow... Impressive!<br>
<br>
If I get it well, the current idea is that there is a reservoir at 3 to<br>
6km deep and a "pipe" up to the surface ?<br>
<br>
>Questions in my mind are both of practical and scientific perspective:<br>
<br>
>- Since we don't expect any conventional seismic/volcanic activity,<br>
will the network record anything of use?<br>
<br>
Well you'll most probably have some tremor linked to the bubbling mud<br>
going up, and maybe some events at deeper locations. Did you measure<br>
anything with the permanent network ?<br>
<br>
>- I have in my hands 5 to 6 Guralp 5TDE (accelerometers). Will they be<br>
able to record noise down to the frequencies of interest?<br>
<br>
I don't have any experience of the 5TDE, could you send the estimated<br>
instrument response? I bet they could be used down to 1Hz or even lower.<br>
Did you do any measurement recently with those ? If yes, it'd be quite<br>
easy to compute some coherency checks on the data.<br>
<br>
>- Related to the previous, what would be the optimum aperture to<br>
deploy the sensors (taking into account we need to extract information<br>
down to 3-6 Km)?<br>
<br>
If you want to "monitor" the "reservoir" you'll need to open the network<br>
quite largely. Aurélien could answer this better than me, but I'm quite<br>
sure you can open one triangle by 5 to 7 km and anther one with a<br>
smaller aperture, both "centered" on the volcano.<br>
<br>
In any case, I'd install them rapidly and check the data after 1 or 2<br>
weeks max.<br>
<br>
ps= don't forget to update to MSNoise 1.5.1 to have the latest bugfixes.<br>
<br>
Best regards,<br>
Tom<br>
<br>
On 17/02/2018 17:33, Ilias Papadopoulos wrote:<br>
> Hello fellow MSNoise users,<br>
><br>
> I have in my hands a case of an erupted mud volcano. The event took<br>
> place between February 12th and February 13th and got attention very<br>
> quickly from media and people in Trinidad & Tobago. I don't know if<br>
> any of you have any experience working with MSNoise and mud volcanoes.<br>
> A high quality drone footage you can find here<br>
> <<a href="https://www.facebook.com/topshotaerialservices/videos/984076211740133/" rel="noreferrer" target="_blank">https://www.facebook.com/topshotaerialservices/videos/984076211740133/</a>>,<br>
> story on the media here<br>
> <<a href="http://newsday.co.tt/2018/02/17/mud-volcano-goes-quiet/" rel="noreferrer" target="_blank">http://newsday.co.tt/2018/02/17/mud-volcano-goes-quiet/</a>>.<br>
><br>
> I am thinking of setting up a project around it, but since there is<br>
> not much information as to what to expect, I seek advice from all of<br>
> you. According to geologists here, the whole thing has gone dormant on<br>
> the surface. There is no volcanic activity, hard rock or magma<br>
> movement underneath. Some studies propose a disturbance down to 3 or 6<br>
> Km of mud and gas intruding the younger harder formations.<br>
><br>
> Questions in my mind are both of practical and scientific perspective:<br>
><br>
> - Since we don't expect any conventional seismic/volcanic activity,<br>
> will the network record anything of use?<br>
><br>
> - I have in my hands 5 to 6 Guralp 5TDE (accelerometers). Will they be<br>
> able to record noise down to the frequencies of interest?<br>
><br>
> - Related to the previous, what would be the optimum aperture to<br>
> deploy the sensors (taking into account we need to extract information<br>
> down to 3-6 Km)?<br>
><br>
><br>
> Any ideas, suggestions or advice are appreciated.<br>
><br>
> Ilias<br>
><br>
><br>
><br>
><br>
<br>
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</blockquote></div></div>-- <br><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><span style="color:rgb(34,34,34);font-size:12.8px;line-height:normal;font-family:tahoma"><font color="#000000">==========================</font></span><div style="color:rgb(34,34,34);font-size:12.8px;line-height:normal;font-family:tahoma"><font face="Times New Roman" color="#000000"><br></font></div><div style="color:rgb(34,34,34);font-size:12.8px;line-height:normal;font-family:tahoma"><font face="Times New Roman" color="#000000">Postdoctoral associate</font></div><div style="color:rgb(34,34,34);font-size:12.8px;line-height:normal;font-family:tahoma"><font color="#000000"><span style="font-family:"times new roman"">Department of Earth, Atmospheric and Planetary Sciences</span><br style="font-family:"times new roman""><span style="font-family:"times new roman"">Massachusetts Institute of Technology</span><br style="font-family:"times new roman""><span style="font-family:"times new roman"">54-526</span><br style="font-family:"times new roman""><span style="font-family:"times new roman"">Cambridge, MA 02139-4307</span></font></div><div style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:12.8px;line-height:normal"><font color="#000000" style="font-family:tahoma"><span style="font-family:"times new roman"">phone: </span></font><font color="#000000" face="Times New Roman">617-25</font><span style="color:rgb(0,0,0);font-family:"times new roman"">3-5051</span></div><div style="color:rgb(34,34,34);font-size:12.8px;line-height:normal;font-family:tahoma"><span style="font-family:"times new roman""><font color="#000000">e-mail: <a href="mailto:mordret@mit.edu">mordret@mit.edu</a></font></span></div><div style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:12.8px;line-height:normal"><font face="Times New Roman" color="#000000">web: <a href="http://web.mit.edu/mordret/www">http://web.mit.edu/mordret/www</a></font></div></div></div>