Seismic Event Information at the DMC
Overview Seismic Event Information at the DMC
ISF format
with DMC extensions
Search Event
Catalogs
Browsing and Requesting
Event Data from IRIS
WEED
UNIX-based, stand-alone application that assists
users in making event-based requests. Users can generate their own station or
event files by querying the database. Learn about WEED
User Options.
Catalog Definitions
- NEICALRT
-
List distributed by NEIS (National Earthquake Information Service) of
the USGS via email and used to trigger the IRIS SPYDER® system. These
events are NOT included in the "PREFERRED" catalog algorithm
because they are redundant (of FINGER) and do not include all events
reported by FINGER.
-
- FINGER
-
List distributed by NEIS (National Earthquake Information Service) of
the USGS through the "finger quake@gldfs.cr.usgs.gov" service.
The earthquakes on the "quake" list have been reviewed by a
seismic analyst. However, in the interest of timeliness, locations and
magnitudes are entered once and not updated on the list.. This list contains
data for the past 7 days. Once an event rolls off the list it appears
on the QED (see next definition).
- QED
-
Quick Epicenter Determinations - distributed by the USGS NEIS 7 days behind
real time. These data are extremely preliminary and the parameters of the
earthquakes are subject to change as more data are used to relocate the
earthquakes. The QED rolls over to the WHDF (see next definition).
-
- WHDF
-
Weekly Hypocenter Data File - distributed by the USGS NEIS. Covering the
time period following the Monthly data up to four weeks behind the current
week. The Weekly PDE (Preliminary Determinations of Epicenters) data are
replaced by the Monthly PDE data as soon as they become available.
-
- MHDF
-
Monthly Hypocenter Data File - distributed by the USGS NEIS. This list
is the most complete computation of hypocenters and magnitudes done by
the USGS NEIC. It is normally produced a few months after the events
occur. The publication is called "preliminary" because the "final"
computation of hypocenters for the world is considered to be the Bulletin
of the International Seismological Centre (ISC), which is produced about
two years after the earthquakes occur.
-
- ISCCD
-
Bulletin of the International Seismological Centre (ISC). List of earthquakes
two years behind real time.
-
- PREFERRED (SeismiQuery
option only)
-
When this selection is made in SeismiQuery, the resulting list of events
will include events selected from the catalog that is considered to be
most accurate for that time period. The order in which the catalogs are
listed above is the reverse order in which events will be selected as "preferred." (That
is, the ISCCD being most preferred and so on.)
- SPYDER
-
SPYDER® is IRIS DMC's near-real-time data retrieval system.
SPYDER® data
is not QCed but is available almost immediately after an event.
To browse and request SPYDER® data, use WILBER
II — our
Web-based request tool.
-
- FARM
-
Fast Archive Recovery Method - FARM is IRIS DMC's readily-accessible
seismic event data repository (delayed, QC'd, full data set).
-
The most
notable events are larger than a magnitude of 5.5 (Mw). For this
reason, the DMC routinely pre-assembles data from earthquakes
that exceed magnitude 5.7 at any depth, and for events down to
magnitude 5.5 if the depth is greater than 100 km. These pre-assembled
data sets are called FARM Products and consist of data collected
from stations all over the world and from many different networks.
-
Since most seismic phase arrivals occur
within 60 minutes of the initial phase arrival at a seismic station,
we extract a 60 minute window for broadband, mid period, and
short period channels. Long period windows are a function of
magnitude, tuned to record the maximum number of Rayleigh phases
for larger events. FARM products become available 6 weeks to
3 months after the event and are most easily accessed using WILBER
II.
-
|
