This application implements PyOcto phase associator software which performs efficiently the association of arrival times that have been picked manually or automatically. As a result the application returns QuakeML file containing detected events together with their hypocenter locations and assigned arrival times. The application can be used in two ways: using a 1D velocity model (from a file) or using a 0D model (i.e. providing constant values of the velocity of seismic waves).

To obtain more general information about working with applications within the Platform, see Applications Quick Start Guide.

CATEGORY Source and Shaking Parameters Estimation

KEYWORDS Source location, Seismic event detection

CITATION If you use the results or visualizations retrieved from this application in a publication, then you must cite the data source as follows:

Orlecka-Sikora, B., Lasocki, S., Kocot, J. et al. (2020) An open data infrastructure for the study of anthropogenic hazards linked to georesource exploitation., Sci Data 7, 89, doi: 10.1038/s41597-020-0429-3.
Münchmeyer, J. (2023). PyOcto: A high-throughput seismic phase associator. Preprint at arxiv.org/abs/2310.11157.

Input file specification

The application requires:

QuakeML file containing arrival times (from any time range)
XML file containing a seismic network inventory with stations coordinates

For best performance, also use:

velocity model file (in standard format on the platform - .mat)

EPISODES Platform Documentation > Phase Association user guide > Fig1.PNG

Figure 1. Application input files specification.

Filling form values

The application form, in case of using velocity model file, consists of five required parameters - see Figure 2. The first three of them parameterize area in which events can be detected and located. Next two describe grid size for the 1D velocity model.

EPISODES Platform Documentation > Phase Association user guide > Fig2.PNG

Figure 2. Application form with values filled in case of using velocity model file.

The application form, when using constant velocity model, also consists of five required parameters, two of which are different - see Figure 3.

In this case the first three parameters are the same. However, in this case there is no need to create a grid for the 1D velocity model. Instead, constant velocities for P and S wave have to be provided.

EPISODES Platform Documentation > Phase Association user guide > Fig3.PNG

Figure 3. Application form with values filled in case of using constant velocities.

It is also possible to edit other, more advanced program parameters - see Figure 4, such as:

minimum number of picks (in total)
minimum number of P-wave picks
minimum number of S-wave picks
minimum number of pairs of P- and S-wave picks
time before: The overlap between consecutive time slices
tolerance Velocity model tolerance in s
association_cutoff_distance: Only use stations up to this distance for space-partitioning association
pick match tolerance: Maximum difference between the predicted travel time and the observed time for associating a pick to an origin in the refinement step.
P-wave hint: e. g. P, Pg etc.
S-wave hint: e. g. P, Pg etc.

Figure 4. Application form with advanced options.

Produced output

As a result program return QuakeML file containing list of detected events with assigned arrival times.

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Input file specification

Filling form values

Produced output

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