README
Created January 14, 2015 by N. Lewandowski
Revised February 25, 2015 by N. Lewandowski

Jeanne Hardebeck provided a tab-delimited text file "hypoDD_combined_updated_140218.reloc" of a seismicity relocation catalog to the SSHAC SSC TI Team via Steve Thompson on 2/18/2014. This catalog is an update to the Hardebeck (2010) seismicity catalog.  

This Readme file documents the data in the Earthquake Catalog appendix text file Attachment_F-1.txt. 


The file Attachment_F-1.txt provides an earthquake catalog for M>=0.0 for the period October 2, 1987 to December 31, 2013. 

The file sent by Hardebeck did not contain header information, but is assumed to be standard hypoDD format as was the Hardebeck (2010) catalog. A header line was added by N. Lewandowski to show the format.

The earthquakes are identified by an "ID" that represents the the original event IDs used in Hardebeck (2010). There is no definition of what magnitude scale is used. 


Attachment_F-1.txt contains 22,052 rows of data and one header row. There are 24 columns
Column 1 is ID
Column 2, 3, 4 are Lat, Long, and Depth. Lat and Long are in decimal degrees; Long values are negative. Depth values are in km. A negative depth value implies the event is an airquake.
Column 5, 6, 7 are "X(m)", "Y(m)", and "Z(m)". These are the east-west, north-south, and depth locations (m), respectively, relative to the cluster centroid.
Column 8, 9, 10 are "EX(m)", "EY(m)", and "EZ(m)". These are east-west, north-south, and depth location errors (m), respectively. In the Hardebeck (2010) catalog, these columns were labeled as "not meaningful" as they were computed with LSQR (Paige and Saunders, 1982). They are presumed not meaningful in this catalog as well.
Column 11, 12, 13, 14, 15, 16  "YR", "MO", "DY", "HR", "MI", and "SC". These are the year, month, day, hour, minute, and second the earthquake occurred.
Column 17 is "MAG" - magnitude of the earthquake.
Column 18, 19 are "NCPP" and "NCCS" - the number of cross-correlated P- and S-wave data.
Column 20, 21 are "NCTP" and "NCTS" - the number of catalog P- and S-wave data.
Column 22, 23 are "RCC" and "RCT" - RMS residuals for the cross-correlated and catalog data.
Column 24 is "CID" - cluster index
