ground displacement

General discussions and questions about recurrence plot and recurrence network related methods.
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nicolaslc
Junior
Posts: 1
Joined: Thu Oct 12, 2023 11:38
Affiliation (Univ., Inst., Dept.): Data EndIAvour
Location: Bordeaux, France
Research field: Geosciences

ground displacement

Post by nicolaslc »

Hello,

Following the python book of Martin Trauth, I'm trying to calculate the recurrence plots for time series measuring the displacement of the ground.
These times series are taken on broad areas in France and UK and I would like to test whether RP and CNN models can help me cluster/classify them to subsequently analyse them by groups.

Following the book and the section written by Norbert Marwan, I started with the assumption that the phase space is only one-dimensional (the displacement) from which I can calculate the symmetric distance matrix S and apply a threshold to create the RP.

Is this a first correct approach? meaning I don't need to use an embedding dimension m nor a time-delay tau ? or I am missing something ?

Any help would be appreciable,

Best Regards,
nicolas
AJOM99
Junior
Posts: 2
Joined: Mon Jul 22, 2024 06:10
Affiliation (Univ., Inst., Dept.): University of Houston EAS
Location: Houston, Texas, USA
Research field: Structural Geology

Re: ground displacement

Post by AJOM99 »

It appears we are working on similar problems. The phase space is probably not one dimensional. I only say this because I have been working on reconstructing attractors from creepmeter data. The challenging part for me is detrending the entire signal from the creepmeter, rather than just a segment. It seems to influence FNN results (AMI not so much). I am finding that even after detrending the signal in any case, the first VT mode of the SVD breakdown of the Hankel matrix or embedded dimensions seems to "pull out" the information about the long range trend, while the second, third, and fourth SVD modes form a strange attractor.

Sample rate is 1/10 min
Attachments
Delay of about 6 days
Delay of about 6 days
Screenshot 2024-08-13 at 6.18.01 PM.png (27.32 KiB) Viewed 5704 times
If I take say 6 million minutes of data from a section with strong persistence, it's straight forward to detrend the signal.
If I take say 6 million minutes of data from a section with strong persistence, it's straight forward to detrend the signal.
Screenshot 2024-08-13 at 6.17.49 PM.png (36.26 KiB) Viewed 5704 times
Screenshot 2024-08-13 at 6.17.56 PM.png
Screenshot 2024-08-13 at 6.17.56 PM.png (46.59 KiB) Viewed 5704 times
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