Specification for Data Collection at ISC

Introduction

The ISC collects phase readings and other earthquake bulletin data from over 100 agencies around the world. The data must be sent to ISC in Electronic form as ISC does not accept data sent by fax or on paper. The data collected by ISC is primarily sent by email to the data-collection address : seismoisc.ac.uk

The data sent to seismoisc.ac.uk is passed automatically to the 'capture' program.

Within this program a suite of recognition routines examine each email. They look at the 'From' and 'Subject' lines and also the attached data or attachment filename, in order to recognise that an email comes from a particular agency. This is a vital step as the agency determines the way in which the data is processed. Every agency has an input directory on the ISC server. The recognition routines determine the filename to be used to file the data away in the agency's input directory, whether the data needs to be decoded and which parser should be used to parse the data into the database. This information is passed back to the capture program which then carries out the final parsing of the data into the ISC database.

Approximately 90% of all received data is parsed automatically.

John Eve is the person in charge of the ISC data collection system.

All data-collection queries/issues should be addressed to: seismoisc.ac.uk

Email consistency

As ISC is resource limited and data is received from over a 100 agencies, it is important to keep the process as automatic as possible.

In order to do this, it is very important that agencies are consistent with their email Subject lines and attachment-filenames.

It would be appreciated if agencies would give ISC advance notice (to seismo@isc.ac.uk) that email addresses are going to change. A new email address results in the data having to be parsed manually.

Registering of Stations

ISC does not enter any phase data into its database for station codes that have not been registered in the International Registry of Seismograph Stations. This is jointly maintained by ISC and NEIC.

It is now very easy to register a new station code. On the ISC web-page click on 'Station Registration' and fill out the form.

This is the quickest, easiest and preferred way of doing this - both for the agency and for ISC. It enables the agency to try out different codes until they find a unique code that they are happy with. Alternatively, the station data can be emailed separately to: seismoisc.ac.uk for ISC to register the station.

If agencies are aware that there is a new station code(s) in their data, they are urged to register the station(s) before sending the data.

It is recognised that many agencies use and report local station codes which are different, in many cases, to the registered station codes. ISC maintains a special file for each agency which equivalences (maps) local codes to registered codes. Hence, the registering of a new code does not necessarily mean that the agency has to change its local code in its data files, ISC just needs to know which registered code is equivalent to each local code.

It should be noted, however, that the ISC bulletin and database will only report stations by their internationally registered codes and not by their local codes.

Bulletins or separate hypocentre/phase files

Wherever it is possible ISC prefers to receive data in a Bulletin form - where the agency has linked phase readings to seismic events - rather than sending only a list of phase readings with or without a separate list of hypocentre solutions and other parametric information. Data received in a Bulletin form enables the local expertise of the agency to be directly incorporated into the ISC database and bulletins and is likely to reduce the number of mistakes in ISC's automated phase-association process that will have to be corrected manually by ISC Bulletin editors.

Where this is not possible ISC gladly accepts the separate hypocentre and phase files.

Data Formats

There are now a number of well-recognised standard formats for seismic data - ISF/GSE/Nordic. Information on the IASPEI Seismic Format (ISF) can be found at - http://www.isc.ac.uk/doc/code/isf/isf.pdf"` (Alternatively, go to the ISC web-page and follow the 'Document Index' link).

Agencies using bespoke formats or old formats like Telex are urged to look seriously at moving to one of the standard formats. Anyone who wishes to incorporate Focal Mechanism data into their data files should look at ISF and Nordic formats.

Where it is not possible to move to a standard format for historical or resource reasons, it is important to be consistent, checking that the latest data file is the same format as the previously sent file. This is particularly relevant to formats which use tabs and/or spaces between data-columns. If tabs are used, then spaces should not be used and vice-versa.

When a new bespoke format is created, it is appreciated if a detailed description of the format is sent ahead of the real data, in order that a parser can be written in time for the receipt of the data.

Indication of event types

It is very helpful to ISC and important to the seismological sommunity to know the type of an event, whether it is an Explosion/Mining-related/Earthquake/Volcanic event/etc. The major formats enable the type to be incorporated into the data. Otherwise, this information can be conveyed by Comments.

Data-filtering

We ask agencies to send data for all events without filtering eg - on a magnitude basis. This enables our seismologists to get a fuller picture of each situation. Moreover, even if an event does not meet ISC criteria for being reviewed by ISC seismologists, the information is valuable to the seismological community and will be made available in the ISC Comprehensive Bulletin.

Amplitudes/Magnitudes

IASPEI has made new recommendations for magnitude determination. Please refer to the 'IASPEI Standard Amplitude/Magnitude' on the ISC website for details.

ISC will determine magnitudes in accordance with the new IASPEI recommendations starting from the ISC Bulletin of January 2007, and is urging seismological agencies to measure and report amplitudes and magnitudes according to the new standards.

In order for ISC to better understand what magnitudes are being reported by individual agencies - agencies are urged to follow the link:'Agency's practice of Magnitude Determinations' on the ISC website and provide ISC with the information.

April 19th 2007