1. Overview

In order to distribute mobile marine seismology (hereafter “SMM” for its French acronym) data to the scientific community, these data and their associated metadata must be packaged in standard formats and validated. The SMM A-Node helps instrumentation facilities and experiment scientists to work together to deliver and validate these data.

The basic processing unit is a “Campaign”, which covers one cycle of data collection. Basic data and meta data are prepared by the involved facilities, then sent to the A-Node A for further processing and validation. After validation, the A-node sends the data and metadata to the Data Center.

This documentation provides the information necessary for Facilities and Scientists to transmit the necessary data/metadata to the SMM A-node and to validate the results.

Figure Fig. 1.1 shows the relationships between the SMM A-Node, instrumentation facilities and campaign scientists.

Fig. 1.1 Relationship between the SMM A-Node, Facilities, Scientists and the Epos-France Data Center

More information on terminology and naming convention can be found in Appendix 1 : Terminology and Naming Convention

1.1. Users and Roles

Figure Fig. 1.1 shows 2 categories of Users and 2 categories of Roles with respect to the A-node. They are:

Users

Scientist: Providers of experiment metadata and scientific validation.

Facility: Providers of data, subnetwork metadata and technical validation.

Roles

Provider

Furnishes data (Technical) and metadata (Technical and Scientific)

Auditor

Validates the data/metadata consolidated by the A-Node

for a given User, the same person may have both Provider and Auditor.

1.2. Data and Metadata Processing

1.2.1. Processing flow

Data and metadata are processed Subnetwork by Subnetwork. Figure Fig. 1.2.1 of shows which data/metadata are prepared by Scientist and Facility Provider before sending to the A-Node.

Fig. 1.2.1 Processing Flow

A Facility Provider collects raw data from instrumentation, transforms them to “A-node” miniseed, and prepares metadata for each station. For more information see Facility-Provided Data and Facility-Provided Metadata.

A Scientist Provider writes an Experiment metadata file, which covers all SubNetwork`s and is updated at each data collection :ref:`Campaign. For more information, see Scientist-Provided Metadata.

The A-Node receives this data and metadata, rectifies and transforms them, then prepares validation pages for the Facilty and Scientist. More information for the technical auditor is at technical-web and for the scientific auditor at scientific-web.

1.2.2. Processes and Tools

Each processing step is performed by at least one specific tool, and the details should be saved in a provenance file. The tools used may be different from facility to facility, see Scientist: Experiment Metadata Processing and Facility Processing. Below are the steps performed at the A-node.

1.2.2.1. Rectification

Before processing the data, the A-Node validates the consistency between data and metadata such as the network code, the number of stations and the station codes. It also validates the consistency between the Facility-provided Network information and that recorded by the FDSN. Further explanation can be found in the NodeA-Processing section