Minor Data Formatting Error Corrected at the NCEDC

November 23rd, 2002

November 23, 2002

On November 23, 2002, the NCEDC discovered a minor data formatting error in some the MiniSEED and SEED data for days 2002/11/17 through 2002/11/23 (days 2002.321 through 2002.327).

The error is not serious, and does not affect any data values. A "reserved field" in the SEED data record that should be blank was erroneously set to the NULL value.

If you have any retrieved any SEED data from the NCEDC for this this timeperiod, we suggest that you re-retrieve this data from the NCEDC. As of 2002/11/23,16:15 PST, all of the erroneously formatted data has been fixed at the NCEDC.

The NCEDC apologizes for this error. Please contact
Doug Neuhauser if you have any questions.

The NCEDC is a joint project of the University of California, Berkeley and the USGS. Please send us email at ncedcinfo@ncedc.org or fill out our comments form if you have questions or comments about these changes.

Changes to Northern California earthquake catalog search

November 21st, 2002

November 21, 2002

Today the NCEDC implemented modifications to eqselect and catlist, programs which search and reformat earthquake catalogs. These programs are used by the Web catalog search as well as by users with research accounts. The changes will affect the magnitudes reported from searches of the NCSN catalog for northern California.

Previously, if a specific magnitude type was not selected by the user, eqselect and catlist reported magnitude according to the hierarchy: Mw (UCB moment magnitude), Mlm (NCSN local magnitude computed from UCB amplitudes), Ml (UCB local magnitude), Md (NCSN coda duration magnitude), Mx (NCSN amplitude duration magnitude).

In the new version of these codes, the preferred magnitude (as selected by the NCSN) will be reported as the default magnitude. If no preferred magnitude is defined, then eqselect and catlist will use the magnitude hierarchy above for reporting.

The change will bring the reported NCSN magnitudes in line with the CNSS catalog, which has always reported the preferred magnitude. This change will result in different magnitudes being reported from the NCSN catalog (if you are using the default option).

The NCEDC is a joint project of the University of California, Berkeley and the USGS. Please send us email at ncedcinfo@ncedc.org or fill out our comments form if you have questions or comments about these changes.

Updated Web pages for the NCEDC

August 14th, 2002

October 14, 2002

The NCEDC revamped its Web pages this month, with the goal of making the data center easier to use! In addition to updating the look of the Web pages, we have provided new and addition information about the holdings of the data center and added the capability to search the Web pages.

As part of this effort, some pages were renamed and others were removed. If you are having problems finding something, please let us know! And feel free to make any comments on the layout or organization of these Web pages.
The NCEDC is a joint project of the University of California, Berkeley and the USGS. Please send us email at ncedcinfo@ncedc.org or fill out our comments form.

Real-time earthquake information during USGS Internet cut-off

December 6th, 2001

Update on Dec. 9, 2001: The USGS Web sites are back!

On Thursday, Dec. 6, 2001, the USGS was ordered to disconnect all external Internet connections by the Office of the Secretary of the Interior. The order includes email as well as popular Web pages.

Because earthquake reporting is a collaborative effort by the CISN members, earthquake information for California continues to be available to emergency responders and the public.

Real-time earthquake information is available at these alternate Web sites:

The "Did you feel it?" Web pages are unavailable at this time.

Access to the Northern and Southern California Earthquake Data Centers and the Engineering Strong-Motion Data Center is unaffected.

EVT_FAST system provides access to NCSN waveform data

November 16th, 2001

November 16, 2001

The USGS Northern California Seismic Network (NCSN) has recorded seismic waveforms for events in northern California from 1984 through present time. These data are archived at the NCEDC, and are now available to users via the EVT_FAST automated event waveform retrieval system through web and email requests. The EVT_FAST system allows users to request all of the waveforms for a specified NCSN event with a simple one-line request. Users can request event waveform data in one of the following formats:

  • SAC binary
  • SAC ascii
  • AH (XDR)

The NCEDC is committed to distributing all waveform data and corresponding instrument response data in the standard SEED format, and is actively working with the USGS to assemble the required instrument response data for the NCSN waveforms. Until the instrument response meta-data is available, the EVT_FAST system provides a quick and easy way for users to acquire NCSN waveform data.

The EVT_FAST web interface for requesting NCSN event waveform data can be found at: /ncedc/evt_fast_form.html

Documentation on the EVT_FAST request format and email submission can be found at: http://www.ncedc.org/ftp/pub/doc/cat5/EVT_FAST.5

The NCEDC is a joint project of the University of California, Berkeley and the USGS. For more information on this data set, please contact ncedcinfo@ncedc.org.


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