5. Retrieving Data from Data Centers

This section is intended as a small guide to help you choose the best way to download data for a given purpose using ObsPy. Keep in mind that data centers and web services are constantly changing so this recommendation might not be valid anymore at the time you read this. For actual code examples, please see the documentation of the various modules.

Note

The most common use case is likely to download waveforms and event/station meta information. In almost all cases you will want to use the obspy.clients.fdsn module for this. It supports the largest number of data centers and uses the most modern data formats. There are still a number of reasons to choose a different module but please make sure you have one.

5.1. The FDSN Web Services

Available Data Types Format
Waveforms MiniSEED and optionally others
Station Information StationXML and Text
Event Information QuakeML and Text

Note

Not all data providers offer all three data types. Many offer only one or two.

If you want to requests waveforms, or station/event meta information you will most likely want to use the obspy.clients.fdsn module. It is able to request data from any data center implementing the FDSN web services. Example data centers include IRIS/ORFEUS/INGV/ETH/GFZ/RESIF/... - a curated list can be found here. As a further advantage it returns data in the most modern and future proof formats.

5.3. IRIS Web Services

Available Data Types and Formats: Various

IRIS (in addition to FDSN web services) offers a variety of special-purpose web services, for some of which ObsPy has interfaces in the obspy.clients.iris module. Use this if you require response information in the SAC poles & zeros or in the RESP format. If you just care about the instrument response, please use the obspy.clients.fdsn module to request StationXML data which contains the same information.

The interfaces for the calculation tools are kept around for legacy reasons; internal ObsPy functionality should be considered as an alternative when working within ObsPy:

IRIS Web Service Equivalent ObsPy Function/Module
obspy.clients.iris.client.Client.traveltime() obspy.taup
obspy.clients.iris.client.Client.distaz() obspy.geodetics
obspy.clients.iris.client.Client.flinnengdahl() obspy.geodetics.flinnengdahl.FlinnEngdahl

5.4. Earthworm Wave Server

Available Data Types Format
Waveforms Custom Format

Use the obspy.clients.earthworm module to request data from the Earthworm data acquisition system.

5.5. NERIES Web Services

This service is largely deprecated as the data can just as well be requested via the obspy.clients.fdsn module.

5.6. NEIC

Available Data Types Format
Waveforms MiniSEED

The Continuous Waveform Buffer (CWB) is a repository for seismic waveform data that passes through the NEIC “Edge” processing system. Use the obspy.clients.neic module to request data from it.

5.8. Syngine Service

Available Data Types Format
Waveforms MiniSEED and zipped SAC files

Use the obspy.clients.syngine module to download high-frequency global synthetic seismograms for any source receiver combination from the IRIS syngine service.