Geopsy-fk

Signal database preparation

Signal viewer for one group of simultaneously recorded waveforms ready for array processing

This step is performed with Geopsy graphical interface. If you have followed all steps for the preparation of a database, loading coordinates and grouping, you should have now a set of simultaneously recorded waveforms building a group and containing coordinates for each waveform.

Alternatively, you can download here a ready-to-go database file and the corresponding waveform files at this location. Note that you have to re-locate your waveform files as described in detail in this page. Or without a graphical interface:

 geopsy-fk -db lep_ring01_3C.gpy -fix-signal-paths

This database contains two predefined groups: vertical and All 3C. Please test, whether you can view the signals, use drag and drop functionality or check the coordinate settings in the table view or map view. If you display the predefined group vertical in a graphic viewer, you should obtain a picture similar to the one displayed on the right.

Now you can open the conventional frequency wavenumber toolbox by pushing the plugin icon .

The f-k toolbox should open and is now attached to the signal viewer. No other toolbox will now open with the signals you have loaded to the signal viewer. In order to process the same data set by another tool, you have to open them in a different signal viewer window. Note also, that once you close either the f-k toolbox window or the signal viewer, there is no way to undo this action - you will have to start again by opening a new signal viewer and attaching the f-k toolbox to it. Alternatively you can drag your group directly into the f-k toolbox icon. Geopsy will automatically open a new exclusively attached signal viewer for you. Note, for reasons understandable from section testing parameter settings it will be always a graphic signal viewer that is openend.

Conventional f-k toolbox

Let's now have a close look to the individual parameters to be set in the f-k toolbox. There are four main groups of parameters to be considered.

• Pre-processing parameters for excluding data from processing.
• Processing parameters for selecting time windows on the remaining data.
• Processing parameters for selecting narrow frequency bands for processing
• Parameters related to the output of results from f-k processing.

These parameters are laid out in different parts of the f-k toolbox widget. Note, that the toolbox has three main tabs: Time, Processing and Status.

The pre-processing parameters for excluding data from processing follow the same argumentation as the data selection for other toolboxes like H/V processing and can be found in the Time tab.

E.g. one can apply the so-called anti-trigger approach for removing transient signals from the continuous recordings (i.e. excluding those time chunks from processing). The anti-trigger approach can be applied to raw or filtered data. For the detailed settings please look into the description of anti-trigger. Another, second, approach for excluding data from processing is provided via the bad sample approach. For details in setting parameters with the bad sample approach check this page.