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WebDC - Integrated Seismological Data Portal

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What is WebDC?

WebDC is an initiative of GEOFON (GEOFOrschungsNetz, Geo Research Network) and SZGRF (Seismologisches Zentralobservatorium, Seismological Central Observatory) to design tools for a distributed seismological waveform archive structure in Germany and Europe, to implement this structure in cooperation with all interested institutions and to provide a comfortable user interface to this structure . The project is supported by the Deutsche Forschungsgemeinschaf t (DFG, German Science Foundation), GeoForschungsZentrum Potsdam (GFZ, Geo Research Center) and Bundesanstalt für Geowissenschaften (BGR, Federal Institute for Geosciences and Natural Resources).

Project goals

to design a simple, fast and robust Internet data request protocol for waveform and meta data access to distributed data archives,

to design a comfortable web portal for easy and transparent user access to distributed WebDC data bases,

to implement a prototype system in Germany with extensions to European partner networks,

to promote a unified European system of primary and backup archives for continuous data from permanent and temporary networks to guaranty the long term availability of all kinds of seismological data and open and easy user access to it.

What is ArcLink?

ArcLink is the distributed data archive access protocol within WebDC. Following the simple but very efficient appoach of SeedLink real-time communication protocol, ArcLink is designed as a "twin" of SeedLink. Instead of supporting different data acquisition systems through SeedLink plugins, ArcLink Requesthandler plugins support different data archive structures as individual data sources. It supports access both to meta databases (inventory and event information) and waveform archives. Waveform utput is in SEED or MiniSEED format, meta data output in XML or dataless SEED (response information only).

ArcLink Network

ArcLink User Interfaces

ArcLink Node

Request Handler

Configurable parameters:

Maximum number of parallel request handlers (eg., number of requests processed in parallel).
Number of pre-forked request handlers.
Length of request queue.
Maximum number of parallel TCP/IP connections.

ArcLink Request Format

General request format:

REQUEST request_type attributes
start_time end_time network station stream location constraints
...
END

Sample inventory request:

REQUEST INVENTORY instruments=true outages=false logs=true
2005,09,01,00,00,00 2005,09,01,00,10,00 * . restricted=false
2005,09,01,00,00,00 2005,09,01,00,10,00 * * BH* * latmin=50 latmax=60
END

Sample waveform request:

REQUEST WAVEFORM format=FSEED
2005,09,01,00,00,00 2005,09,01,00,10,00 GE WLF BH*
2005,09,01,00,00,00 2005,09,01,00,10,00 GE KBS BHZ 00
END

Request Types

Request Type	Attributes	Product Format
INVENTORY	instruments=true\|false outages=true\|false logs=true\|false	XML
RESPONSE	format=SEED\|XSEED	Dataless SEED XML (XML-SEED)
WAVEFORM	format=MSEED\|FSEED\|XSEED	Mini-SEED Full SEED XML (XML-SEED)
EVENTS	picks=true\|false	XML (QuakeML)

ArcLink Database

ArcLink database has 2 major components:

Inventory DB contains all information that is needed for IDL:iris.edu/Fissures/IfNetwork/Instrumentation and dataless SEED volumes.
Event DB contains event information, such as origins,
magnitudes, pick associations, etc.

These components should be viewed as groups of tables in a single (MySQL, etc.) database. In addition to the two groups, there might be tables that contain user profiles, etc.