An AutoDRM for the U. S. National Seismograph Network

Dr. Ray Buland
National Earthquake Information Center
U. S. Geological Survey
Box 25046 Denver Federal Center Stop 967
Denver, CO 80225, USA
E-Mail: buland@usgs.gov

Introduction

The Federation of Digital Broadband Seismograph Networks (Federation) began considering Data Request Manager (DRM) and Automatic Data Request Manager (AutoDRM) standards in December, 1993. In January, 1994, the Federation adopted the AutoDRM developed by Dr. Urs Kradolfer for use at the Swiss Seismological Service (see the article on the Swiss AutoDRM) as a starting point for their own standard. The Swiss AutoDRM was chosen because it is emerging as a defacto standard within the GSE community (United Nations Committee on Disarmament, Group of Scientific Experts), because it already incorporates many of the features desired by the Federation, and because the e-mail orientation allows service to a much larger international community than more Internet-specific protocols such as ftp.

To gain experience, all Federation members were asked to implement the Swiss AutoDRM as soon as possible. This exercise was intended to determine how completely the AutoDRM could be implemented, given existing databases, and what extensions to the AutoDRM command language were necessary to meet minimum Federation requirements. In the long term, substantial enhancements to the AutoDRM are already being discussed. These include: 1) extending the functionality (e.g., providing station outage information), 2) supporting the (binary) SEED as well as the (ASCII) GSE format for response and waveform information, 3) providing for automated requests between data centers, and 4) improving the convenience of the command language (e.g., providing multiple time intervals per request and wild cards for components). It is intended that changes to the AutoDRM be evolutionary and upward compatible in order to maintain a common look and feel for users from both the Federation and GSE communities.

The USNSN AutoDRM

The U. S. National Seismograph Network (USNSN) has become the second Federation Member to implement the Swiss AutoDRM (the Canadian Seismograph Network had already implemented it prior to the recent Federation meeting, for GSE purposes). The USNSN AutoDRM in its present form follows the philosophy and structure of the Swiss AutoDRM as closely as possible, including implementing all of the functionality in some form and using the same formatting in most cases. Only minor extensions to the USNSN databases were required in this implementation, but the connotation of some of the responses are different from those of the Swiss AutoDRM, due to fundamental differences in missions, networks, databases, and products. Note that all response and waveform data are currently returned in the ASCII GSE format. The GSE format is currently evolving to meet the needs of the third GSE Technical Test. Specifications will be provided through the AutoDRM when they are available.

Minor extensions have been made to existing commands by adding optional arguments. The most important of these is the addition of a channel code as the second argument to commands requesting response (CALIB) and waveform (WAVEF) information in order to support multi-channel (especially broadband) stations. In the USNSN implementation, the channel defaults to BHZ. The station list (SLIST) command also has an optional argument which allows the retrieval of different subsets of the USNSN station list. The data availability (AVAIL) command behaves quite a bit differently than on the Swiss AutoDRM. Since the USNSN database is not event organized, it simply returns the time interval for which the database is currently on-line. Two commands have also been added: station outage (OUTAG) information to meet minimum Federation requirements and channel list (CLIST) information which indicates what channels are available for each station.

To access the USNSN AutoDRM, send mail to autodrm@usgs.gov with the message: PLEASE HELP. Information about how to obtain a users guide through the AutoDRM will be returned. The users guide describes the commands available and how to use them. It also describes several software packages available through the AutoDRM for interpreting the GSE format and converting it to other popular formats.

Acknowledgement

Dr. Urs Kradolfer has freely provided software, consulting services, and encouragement without which this work would have taken very much longer. Note that most of the enhancements discussed above arise from adapting the existing Swiss AutoDRM to an environment for which is was not originally intended and are in no way a reflection on the quality of the original.