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 (limited availability)
Bulletin of the International Seismological Centre (ISC). List of earthquakes two years behind real time.