GEOFON and EIDA Data Archives

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Workmark GFZ Potsdam

Getting started

This site is a portal to the seismic waveform data archives at GEOFON, including the EIDA data holdings. With it, you can request

  1. seismological data (waveforms) and
  2. station lists (Dataless SEED, Inventory XML).

from different data centers spread across Europe.

If you encounter difficulties using the WebDC software, please contact the authors at geofon@gfz-potsdam.de .

The portal allows you to create requests which combine the stations' locations with earthquake lists provided by GFZ or other agencies. See the "Event Controls" box. In this case the event time and coordinates are used to compute approximated arrival times ("onset times") for the P or S wave of the selected earthquakes at the selected stations.

WebDC ArcLink data requests can also be made using the arclink_fetch program.

About the web interface

  1. Waveform data: We offer you the choice of downloading mini-SEED or full SEED volumes. These can be easily converted to other major seismological formats using the rdseed tool.
  2. Metadata: You can also download Dataless SEED and Inventory XML. These formats contain only the station and stream information. They contain information like coordinates, names, codes and instrument responses for certain stations or networks. Dataless SEED files can be decoded by the rdseed program. An inventory XML file is a plain text file that can be inspected by any text editor, but it is recommended that you use a real generic XML parser to extract the desired information from it. A handy tool that allows you to convert XML files to a more linear format is Dan Egnor's xml2.

For restricted datasets, some data centers (including GEOFON) deliver encrypted data. For those cases it is necessary to first decrypt the received data using the password that you will receive in your e-mail. The decryption can be performed by using the OpenSSL tool available on most Linux distributions. For decrypting your data use the following command:

  openssl des-cbc -pass pass:{Your Password} -in {Input File} -out {Output File} -d

If your password contains symbols we recommend that you quote your password (using single quotes) on the command line by using this line instead:

  openssl des-cbc -pass pass:'{Your Password}' -in {Input File} -out {Output File} -d

If you feel you should have access to a data set, contact the responsible principal investigator(s), or the data centre holding the data. (Contacting GEOFON)

Using the web interface

The web interface is built up from boxes. Here are some of the features of each box.

The "Event Controls" box

Use this to select events to compose your request. This powerful tool is an event browser which can query several sources of information.

Catalog Services: At GFZ you can choose events from one of the following public catalog services:

  1. GFZ - The GEOFON catalog (http://geofon.gfz-potsdam.de/eqinfo/.)
  2. EMSC - The EMSC catalog (http://www.emsc-csem.org/Earthquake/.)
  3. USGS - The ANSS Comprehensive Catalog (ComCat) service (http://comcat.cr.usgs.gov/earthquakes/feed/v0.1/search.php.)
  4. XXXX NEIC - A temporary replacement for the NEIC service, at USGS (http://earthquake.usgs.gov/earthquakes/eqarchives/epic/) based on the new Comprehensive Catalog (ComCat). XXXX

Select "Catalog Services" under "Event Information". Then use the pull-down menu under "Catalog Service" to choose the desired catalog. Now you can filter events by:

  • Date interval
  • Magnitude range
  • Depth
  • Location

User Supplied: Alternatively you can upload your own catalog...

The "Station Controls" box

Use this to add channels to your request. The selection of stations can be made according to

  • by geographical coordinates
  • the currently selected events - distance and (back)azimuth are in degrees
  • or by network/station codes.

Symbols used on the pull-down lists are: * = temporary network; + = restricted access (see here)

You can limit the selection to particular types of streams/channels, either

  • by channel code, e.g. BH (for BHE, BHZ, BH1, etc.). Location codes appear before the channel code, e.g. 00BH. You can select multiple types of channel codes by selecting with the SHIFT and/or CTRL keys.
  • by sampling rate - for every station, this will return those streams with a reported sample rate closest to that specified.
The "Event and Station Map" box

Here the events and stations you choose will be displayed. Use the mouse to drag the map around. Use the left SHIFT + Mouse to drag areas for limiting the search of events and stations when the appropriate modules are enabled.

The "Event and Station List" box

The tables here show the events and stations you choose. Use these tables to check which events and stations have been selected by your search criteria. You can interactively remove unwanted items. Your final request will be built from the currently displayed information. You can refine the selection of streams for stations using the "Advanced Stream Filters Control".

Triangles on the column headers allow you to sort rows by the values in those columns.

The "O/R" column shows whether the station is "open" (field is empty) or "restricted" (shown by a red "R").

The "Submit" box

Use this to send your request to a server. You can check the status of your requests using the controls under the "Download data" tab.

The "Recent Requests" box

Here you can check the status of your Arclink requests made during your current use of this service. The usual request group operations (Reroute/Retry/Resend/Delete/Refresh) as well as download links are available on the status popup. Use this box to conveniently download a small number of recent data volumes.

The "Manage Requests" box

Here you can manage all your Arclink requests (including requests made during previous visits). Downloading all your data volumes with a single click is possible if you have jDownloader installed.

The "Console" box

Warnings and other messages appear here. Unwanted messages can be removed by reloading the page, or using the "Clear" button.