Data access
Datasets across the AlpArray Region - the AlpArray Seismic Network
The AlpArray region is defined as the region within 250 km distance from a smoothed 800m contour line around the Alps. The polygon describing this is shown below
Within this region, there are stations operated by existing permanent networks that are complimented by the dense AlpArray Seismic Network temporary experiment. Together, the permanent and temporary networks are the AlpArray Seismic Network (AASN).
With very few exceptions, all broadband stations operating within the AlpArray limits belonging to permanent seismic networks are available to the community (and hence also the AASN) without restriction, and the highest available sampling rates - in general this means HH? channels with sampling rates of at least 100sps. All these permanent stations have realtime communications and data is available in the archive typically within minutes of realtime. Data can be downloaded from these stations using EIDA tools ( EIDA data access portal, fdsnws). These stations are operated under their usual network codes, eg. CH for the National Swiss Network, FR for RESIF etc.
The AlpArray temporary network has network code Z3, all stations in the temporary stations use this network code independent of where or whom has installed and operates the station. All Z3 stations are broadband - at least 30s corner period, though the majority are at least 120s, and are sampled at at least 100sps. Around half of Z3 stations stream data in realtime or with small delays, the rest have no communications. For stations with no communications, its is targeted to make data available within 3 months maximum. All Z3 data are permanently archived at EIDA nodes, and the waveforms are available using fdsnws and the EIDA data access portal.
The official period of the AASN started on 1.1.2016 and ended on 1.4.2019. Despite the official end of the AASN, data collection is expected to continue into 2022 at many stations. The Z3 network code ends on 30.12.2022. Though some staiotns have been dismantled, many stations have been hardened and integrated into permanent networks.
Data Restriction for Z3 network
Data from the entire Z3 network is open (since 1.4.2022).
Past restrictions:
From the begining of the netwrork until 1.4.2020, data was avaialble on EIDA only with password protection via EIDA services to registered members of institutions part of the Core Group in order to carry out research following approved topics.
From 1.4.2020 (one year after operation of the AlpArray Seismic Network was ended) until 1.4.2022, the waveform data was also made available to the entire AlpArray Working Group.
Virtual Network Code _ALPARRAY
In order to identify and facilitate easy and rapid access to all AlpArray Seismic Network stations, we have created a virtual network for AlpArray - _ALPARRAY. This network code can be used using both the EIDA data access portal and scripts using fdsnws_fetch.
The rules defining which stations are included in _ALPARRAY are:
- includes all permanent stations that are within the 250km distance polygon AND providing HH? channel data AND operational at any time between 1.1.2016 and 1.1.2020
- include all Z3 network code stations (temporary AlpArray stations)
There are a number of exceptions that are also included (whitelisted):
- G.ECH, RD.LOR, RD.ORIF, RD.PGF (stations only recording at 20sps)
- CR.BRJN, CR.KALN, CR.MOSL, CR.NVLJ, CR.OZLJ, CR.PTJ, CR.RIY, CR.UDBI, CR.ZAG (stations only recording at 50sps)
- CR.HVAR, CR.KIJV, CR.MORI, CR.STON (50sps AND outside polygon)
- HS.ERNH (station just outside polygon)
Data Access - Summary of Data Archival
- all temporary AASN stations are collected using network code Z3 (note Complementary Experiment have their own network codes, eg XT for EASI)
- Z3 waveform data is archived across various EIDA Nodes. The EIDA node archiving a particular station depends on the agency that collects the data rather than the country the stations are placed in.
- SED / ETHZ EIDA node archives SED/SEG ETHZ data
- INGV node archives INGV data
- RESIF node archives data collected by French institutions
- GFZ / BGR / LMU nodes archives data collected by German institutions
- ODC node archives data collected by institutions from Austria, Hungary, Czech Republic.
- waveform data is available (without password or token since 1.4.2022) via the EIDA arclink portal OR fdsnws/event
- station metadata can be explored using EIDA fdsnws (see http://www.seismo.ethz.ch/en/research-and-teaching/products-software/fdsn-web-services/ for details on fdsnws:station). Eg.:
Data Access - Access Details
- Fdsnws( target: advanced users - for scripting and batch jobs):
- fdsnws_fetch is a small python script that uses fdsnws operated at the EIDA nodes and the EIDA routing service.
- fdsnws_fetch is part of SeisComP3 distribution, but can also be downloaded directly. Further information can be found at https://www.seiscomp3.org/doc/applications/fdsnws_fetch.html
- EIDA Portal (target: exploring datasets, irregular download)
- http://www.orfeus-eu.org/data/eida/
- can select specific network codes, eg. CH or Z3, or _ALPARRAY
- Obspy fdsnws client (target: Obspy users - for scripting and interactive use)
For a complete documentation of Obspy refer to http://docs.obspy.org/