An Automatic Data Request Manager (AutoDRM)

Urs Kradolfer
Swiss Seismological Service
ETH-Honggerberg
CH-8093 Zurich, Switzerland
Phone 41-1-633-2656
Fax 41-1-2556
e-mail kradolfer@seismo.ifg.ethz.ch

Many seismological observatories have their seismograms and other important data (as e.g. locations of seismic events) available on-line in digital form. Most of these observatories are connected to an electronic mail network, and many of them have Internet connection. These advances allow the exchange of seismological data (parameters and waveforms) between different observatories for alert, monitoring and research purposes.

In order to automate data exchange and to free the observatory personnel for other tasks, a fully Automatic Data Request Manager (AutoDRM) has been developed and implemented at the Swiss Seismological Service. The basic concept is the following:

While a Data Request Manager (DRM) is a program that allows interactive browsing through stored data by directly accessing a computer, the Automatic Data Request Manager reads incoming requests in the form of e-mail and transmits the response (typically) back to the sender. The implementation of a system that processes incoming requests automatically not only facilitates the gathering of supplemental data at other observatories, it also reduces the workload at the site where such a system is installed. Since installing the AutoDRM at the Swiss Seismological Service, our staff no longer has to deal with magnetic tapes, floppy disks, parcels, and envelopes to simply send a digital seismogram to a user who has requested it. Users requesting data are referred to our AutoDRM, where they can retrieve available data at any time.

In comparison with a data exchange system that requires a full Internet connection, using e-mail as the transport media for messages between computers allows a much larger community of scientists to access data.

AutoDRM may be viewed as an interface between local storage management, local formats (which are usually different at each seismological center), and the remote user, who should not have to be concerned with local formats. The incoming request consists of simple key words. To a great extent, AutoDRM makes use of existing programs at the site where it is running: AutoDRM receives the data request, runs the existing local program to retrieve the desired data, and then writes it to the file to be transmitted to the sender of the request. Thus, to implement an AutoDRM using existing programs, only a minimum of programming needs to be done.

During mid-1991 the first prototype version of the AutoDRM was developed and installed at the Swiss Seismological Service. During the first two and a half years of operation, AutoDRM responded to more than 4400 requests from users in 23 countries. The frequency of the requests is rapidly increasing: the last 2600 requests arrived during the second half of 1993. Most users request our locations for local, regional, and teleseismic events and many request waveforms recorded by the Swiss network stations.

How to use the AutoDRM

On Internet and many other networks, the e-mail address of AutoDRM is:

AUTODRM@SEISMO.IFG.ETHZ.CH

The X.400 address is:

C=CH; ADMD=ARCOM; PRMD=SWITCH; O=ETHZ; OU=IFG; OU=SEISMO; S=AUTODRM

We recommend that new users first send an e-mail to the AutoDRM with the text "please help". Instructions on how to request a user's guide will then be sent automatically, including examples of request mails. Users will also be given the correct e-mail address that should be used as return address in all subsequent request mails.

A typical request mail might appear as follows:

BEGIN
DATE1 199401200200
DATE2 199402021430
DETEC
EMAIL user@host.domain
STOP

In this example, the user desires a list of the detections (and locations, if available) from January 20, 1994, 02:00 UT to February 2, 1994, 14:30 UT. The AutoDRM will send its response to the electronic mail address of the user, which in this example (second last line) is user@host.domain.

The next example shows how waveforms and calibration information from two stations (OSS and SLE) may be requested for a specific time interval:

BEGIN
DATE1 199402020144
DATE2 199402020146
WAVEF OSS
WAVEF SLE
CALIB OSS
CALIB SLE
FTP myfile
INTER nnn.nnn.nnn.nnn
EMAIL user@host.domain
STOP

The calibration information for a specific station includes the complete transfer function in the form of poles and zeros plus the corresponding scaling factor. The waveforms are transmitted in compressed form in GSE format. The source code of a Fortran program that includes the compression and decompression algorithms can also be requested from AutoDRM, thus making it easy to read and reformat the received seismograms. The use of the FTP and the INTER options at the end of the request mail implies that the output of the AutoDRM is not sent via e-mail but is automatically transferred as the file myfile via FTP to the user's computer with the Internet address (in the dotted-quad form). Only a short notification e-mail will then be sent to the user. If the FTP option is set but the INTER command is omitted, the response is stored on our disk and a short e-mail is sent to the requester, giving instructions on how the file may be retrieved via FTP. By using the FTP option, larger amounts (up to several megabytes) of data may be retrieved. Otherwise, the size of a single response by e-mail is limited to approximately 100 kilobytes. The user's guide describes another method, mail-splitting, which allows larger amounts of data to be retrieved by e-mail.

The current version of AutoDRM should still be regarded as a prototype that may have to be modified or extended to meet specific needs of the GSE or the Federation of Digital Seismograph Networks (FDSN). However, the seismological community would greatly benefit if all AutoDRMs were to follow an agreed standard, even though the kind of data provided by specific organizations may vary. An absolute minimum standard should specify the way in which a potential user may request a user's guide from the specific AutoDRM.