Changes to the NCSN/NCEDC catalog
The NCEDC has migrated all NCSN phase, catalog, and waveform information from ASCII files into the CISN database. This migration necessitated the following changes.
Formerly the catalog referenced historic events without
waveforms for the period
1966/07 - 1998/12 using negative event ID numbers. During the
migration of the catalog into the CISN database, all 228,690
negative event ID numbers were mapped to positive event ID
numbers (download the file "2008-07-18.mapping" from
In addition, on 2007/06/22 7,539 event ID numbers
for earthquakes detected by NCSN real-time systems were
to event ID numbers detected by the CUSP system but not yet reviewed
by analysts. Most of the latter events are aftershocks of the San
Simeon and Parkfield earthquakes. The association of the real-time
arrival time data with the seismograms recorded by the CUSP system
allows analysts to efficiently review these aftershocks and make the
associated event waveform data available to the user community.
Channel names of seismograms (March 1984 - present) and phase data
(July 1966 - present) have been
from a non-SEED Station Network Channel nomenclature
to a SEED
(Station Network Channel Location) nomenclature. The mapping of old
(columns 9-12) to SEED (columns 127-129) is described in the NCSN
Station List Format document. The channel name remapping
includes another benefit besides the adoption of the standard SEED
channel naming. We have deleted seismograms and phases from
non-existent and discontinued stations, and we have renamed channels
that were initially recorded under the wrong name. These
now-corrected naming errors affected thousands of seismograms and
phases, but probably did not corrupt many earthquake locations.
- The NCSN/NCEDC catalog search interface now retrieves information from the NCEDC database rather than the original NCSN flat hypoinverse files.
The NCEDC apologizes for any inconvenience these changes cause. Please contact the NCEDC if you have any questions about these changes.