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Data Handling Applications are distinguished from Data Processing Applications because they perform relatively simple data transformations, resulting to data as well. On the contrary, Data Processing Applications perform specific analyses and methods, utilizing data in order tio produce more sophisticated results, not just simple data elaboration/transformation. The Data Handling Applications available in the IS-EPOS web platform, are described in this section:

  • SEED to SAC Converter
  • Ground Motion Parameters Tool
  • Seismogram picking tool
  • Catalog Filter
  • Magnitude Conversion
  • Signal download tool 
  • Waveform Download tool
  • Time-Series Builder
  • Catalog Export
  • GDF Export


    Description of Data Handling Applications:
  • SEED to SAC Converter

This application uses seed files (uploaded from the episode data or imported from the episode catalog available in the workspace) as input, to convert the signal into SAC format. The User may select from 'Actions', 'Use in Application' and then 'SEED to SAC converter' (Figure 1). Then the screen shown in Figure 2 appears and the User just clicks on the button 'RUN' to execute the conversion.  

Figure 1.

The outputs (red field, Figure 2) are created soon and are available for downloading. Alternatively, another SEED file can be used in the application by clicking 'Change File' tab and selecting an appropriate SEED file from the workspace.

Figure 2.

  • Ground Motion Parameters Tool

This Application joins a Seismic Catalog (1st input)  and a Ground Motion Catalog (2nd input) into a joined catalog used for Ground Motion Prediction (Figure 3). Once the User clicks on the 'RUN' tab and calculations are performed, the joint catalog appears on the screen providing all the available options and functions that Catalog provides (see 'AH Episodes'). 

 

Figure 3.

  • Seismogram picking tool 

'Seismogram picking tool' takes as input seed files. The application interface is shown in Figure 4. Here the User can pick phases or points from the given waveforms (also see Waveform "Viewer guide" section in "Visualizations" chapter). The number of picked phases are counted by the system. Once the picks have been chosen, the User may proceed to further analysis by clicking the green 'RUN' button (Figure 4.). The User can now recall the output file ('picks.xml'), for any Waveform-based application (i.e. 'Moment Tensor Inversion', 'Earthquake Spectra', 'Source Location'). Optionally, the user can select the seismic events (second input, top of Figure 4) from the seismic catalog, or postpone this action for after selection of the application to perform. 

Figure 4.

  • Catalog Filter

This is an application for filtering seismic catalogs. The product is a new catalog filtered upon the User's parameters setting. The input file is a seismic catalog that can be uploaded from 'Change Input' tab (shown in the yellow frame of Figure 5). Next, the User may perform various filtering according to the values of the attributes assigned in the catalog. The User may choose one of these attributes (as ID, ML, Lat etc, displayed in Figure 5) and provide the values he/she wishes, selecting among 'Select all values' (e.g ID field, Figure 5), 'Select Range' (from the calendar - Field 1, Figure 5, or by typing values range - Field 1, Figure 5) and 'Select list of values' (Field 3 Figure 5).

Figure 5.

Alternatively, the User may apply interactively spatial filtering by clicking in the "Select events from map" tab (depicted by the upper green box in Figure 5). This option grants to the User the possibility to select data, spatially constrained by a predefined shape (numbers 2-4 in Figure 6):

1) No draw option.

2) Draw a polygon.The User may select data into a polygon drawn after clicking on different points of the map. To close the polygon, the User has to double click on the last point, such that this point will be connected with the first one.

3) Draw a rectangle. To select data into a rectangular the User has to click on a point of the map and move the cursor to any direction. A second left mouse button click will restrict the selected area at its current state.

4) Draw a circle (option demonstrated in Figure 6). To select data into a circular the User has to click on a point of the map and move the cursor to any direction. A second left mouse button click will restrict the selected area at its current state. Note that the first click on the map defines the circle's center.

Figure 6.

As soon as the filtering criteria have been defined, the User shall click on the 'RUN' button (green button at the bottom of Figure 5) to apply the those criteria. The User may also select the 'Preview Selection on map' tab (indicated by the green frame, at the bottom of Figure 5) in order to view an illustration of the events from the original catalog (red circles) and the events included in the filtered catalog (green circles). A new catalog ('catalog.mat') has been created and it is available for any further processing. In addition the system provides all the information and applications that are valid for the original catalogs (see "AH Episodes" Chapter, for details).

 

  • Magnitude Conversion

'Magnitude Conversion' is a application used for establishing linear relationships between different magnitude scales, which can be later used for conversion of magnitudes from one scale to another. The input file is the seismic catalog that can be uploaded from 'Change Input' tab (shown on right side of Figure 7). The application can be performed only in datasets in which more than one magnitude scale (or, alternatively, 'Energy' or 'Seismic Moment' can be introduced as inputs as well) is assigned for the seismic events (e.g. ML and Mw). The parameters that the user has to set/choose are also shown in Figure 7:

Figure 7.

  • Choose first vector to compare: The user may choose among the different magnitude scales available in the catalog.
  • Choose second vector to compare: The user may choose among the different magnitude scales available in the catalog.
  • Regression Method: Three different regression methods can be used - General Orthogonal Regression, Standard Least Squares and Inverted Least Squares.
  • Error Variance Ratio: A float number should be assigned here (default is 1). Note that this option is only valid when General Orthogonal Regression method, is chosen.

The outputs that the application produces are:

  •  A report with the parameters (slope and intercept) of the regression process and some associated statistical parameters (Figure 7)
  • Vectors of the first, second magnitude selected, together with the vector of the new (converted) magnitudes obtained by the application of the regression equation.
  • A figure with one magnitude scale plotted versus the other one (scatter plot) and the linear regression curve (Figure 8). Zooming option is enabled for this Figure.

Figure 8.

 

  • Signal download tool

This applications extracts seed files and event files from a selected catalog into the User workspace. These extracted files can be used later on at any application dealing with waveform processing, including 'Spectral Analysis', 'Source Location', 'Moment Tensor Inversion' and 'Seed response calculation'. This is an alternative way of exporting seed files instead of searching into the episode database. The User needs first to select a catalog from the workspace and click subsequently on 'ACTIONS', 'USE IN APPLICATION' and 'Signal download tool' tabs, as indicated by the red boxes in Figure 9.

Figure 9.

After this step, the list of events appears in the screen as shown in Figure 10 and the User is requested to select an event for extracting event information and seed file. The User may also chose downloading between 'Seed Signal', 'Accelerogram Seed Signal', or 'All', by ticking on the respective box shown at the bottom left corner of Figure 10.Then, the output files are extracted after clicking on the 'RUN' button (green button, bottom Figure 10). Those files are stored in a Signal Download folder, into the User's workspace and can be further used as input in several applications as mentioned above.

 

Figure 10.

 

  • Waveform Download tool

This application allows for ordering parts of continuous waveforms for specific dates and stations as processed by Seiscomp. The User needs to upload the application from the applications repository to the personal workspace. The preparation of the waveform is executed by Arclink-fetch. The User has to select the respective episode and time period of interest, (as shown in Figure 11). For selection of the the time period the User may either set values to the 'Start' and 'End' point, or specify the 'Start' point and the duration (length) of the periods he/she wishes to study. After this the User selects among the channels and the stations available for each episodes and clicks on 'RUN' button. A *.seed file is soon to be created, and it can be furthered processed within other applications, such as: 'FOCI', 'Waveform Analysis' or 'Seismogram picking tool'.

Figure 11.

  • Time-Series Builder

This application is used to select appropriate time series from the cumulative events distribution plot. The User uploads the catalog of interest from the personal workspace (change file tab - Figure 12). Then, after clicking on 'SHOW PLOT' tab, the starting and ending points of the period of interest are selected by clicking on certain points (starting and ending point) of the cumulative events curve (Figure 13). Running the application, creates a time series matlab file, which can be downloaded, plotted, or used in further processing of time series in particular by the following applications belonging to 'Correlation Analysis application package' (Technology-seismicity interaction): 

  • Autocorrelation
  • Cross correlation
  • Coefficient of randomness
  • Priestley-Subba Rao (PSR) Test

Figure 12.

 

Figure 13.

  • Catalog Export

This Application Exports a Catalog MATLAB file as a spreadsheet file (in XLSX format). In doing so, the User selects from the Catalog actions list 'USE IN APPLICATION' and then 'Catalog Export' (Figure 14). After clicking on the 'RUN' button, the catalog is converted to .xlsx format, which can be downloaded by the User (Figure 15).

Figure 14.

Figure 15.

  • GDF Export

This application exports a GDF MATLAB file as a spreadsheet file (in XLSX format). In doing so, the User selects from the GDF dataset actions list 'USE IN APPLICATION' and then 'GDF Export' (Figure 16). After clicking on the 'RUN' button, the catalog is converted to .xlsx format, which can be downloaded by the User (e.g. Figure 15).

Figure 16.

 

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