Last updated on August 12th 2016.

Note

The following links shows the example project as it should be just before step 4. You can use this to check your progress or restart the tutorial at this very point.

After Step 5: Waveform Data

Note

This part is not actually necessary for the tutorial but most likely for any real work application.

LASIF comes with a collection of scripts that help downloading waveform and station data from all data centers implementing the FDSN web services. This largely amounts to data from Europe, Northern America, Brazil, and New Zealand. If your inversion requires data from other places, you’ll have to retrieve it on your own.

Data are downloaded on a per event basis. The config.xml file contains some specification to detail the download.

\$ lasif download_data GCMT_event_TURKEY_Mag_5.1_2010-3-24-14-11


The command just tries to download everything it can within your chosen domain, both the waveforms and station metadata. It queries successively queries all known FDSN data centers and integrates all data. It accounts for the domain borders and possible domain rotations. It is furthermore influenced by the following parameters in the config.xml file:

• seconds_before_event: Used by the waveform download scripts. It will attempt to download this many seconds for every waveform before the origin of the associated event.
• seconds_after_event: Used by the waveform download scripts. It will attempt to download this many seconds for every waveform after the origin of the associated event. Adapt this to the size of your inversion domain.
• interstation_distance_in_m: The minimum distance between two stations so that data from both would be downloaded in meters. If stations are closer than that only one is downloaded.
• channel_priorities: The priority in which channels will be chosen from each station.
• location_priorities: The priority in which location codes will be chosen from each station.

Depending on the domain size, event location, and origin time, this can take a while. Executing the same command again will only attempt to download data not already present. All waveform data will be placed in DATA/EVENT_NAME/raw and all station data in STATIONS/StationXML.

Note

At this point it is worth mentioning that LASIF keeps logs of many actions that the user performs. All logs will be saved in the LOGS subfolder.