# A workflow for building an automatic earthquake catalog from near-real time DAS data recorded on offshore telecommunications cable in central Chile.

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Marie Baillet, Alister Trabattoni, Clara Vernet, Martijn van den Ende, Diane Rivet
Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, IRD, Géoazur, France
Contact: baillet@geoazur.unice.fr

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das

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## Workflow description on POST data

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1. Automatic phase picking with PhaseNet¹

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2. Phase association with GaMMA²

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4. Local magnitude⁴

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5. Magnitude of completeness map

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## Workflow application on ABYSS data

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### For 1 day of data

* 777 547 picks

* 177 events

* 0.8 ≤ Ml ≤ 3.4

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Fs = 62.5 Hz
Sps = 15 m

1 day recording
5 years recording

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La Serena - North
(SRN)

La Serena - South
(SRS)

Concon - North
(CCN)

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### Automatic catalog processing

1. Data acquisition
   in Chile

2. Data transfer
   300 GB/day

3. Local hard drive
   storage in France

4. Generate a daily
   earthquake catalog

5. Store the results in a
   SQL database
   compatible with

6. Long term tape
   drive storage

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<QuakeML>

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### QML database visualization

sismoazur.oca.eu

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#### Query requests on the online catalog on:

* Dates (start, end)

* Geographic area (latitude, longitude)

* Event type (earthquake, quarry blast, explosion)

* Output formats (Web, Text, CSV, QuakeML)

## DAS data processing with Xdas

* Open source Python library

* Work with huge labeled N-dimensional arrays

* Provides the classical signal processing tools

* Enables I/O capabilities with any DAS formats

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### DataArray architecture:

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### DataCollection architecture:

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### References:

1. Weiqiang Zhu, Gregory C Beroza, PhaseNet: a deep-neural-network-based seismic arrival-time picking method, *Geophysical Journal International*, Volume 216, Issue 1, January 2019, Pages 261–273, https://doi.org/10.1093/gji/ggy423

2. Zhu, W., McBrearty, I. W., Mousavi, S. M., Ellsworth, W. L., & Beroza, G. C. (2022). Earthquake phase association using a Bayesian Gaussian mixture model. *Journal of Geophysical Research: Solid Earth*, 127(5), e2021JB023249.

3. Kissling, E., W.L. Ellsworth, D. Eberhart-Phillips, and U. Kradolfer: Initial reference models in local earthquake tomography, J. Geophys. Res., 99, 19635–19646, 1994.

4. B. Gutenberg, C. F. Richter; Earthquake magnitude, intensity, energy, and acceleration. *Bulletin of the Seismological Society of America* 1942;, 32 (3): 163–191. doi: https://doi.org/10.1785/BSSA0320030163