README.txt file to accompany the earthquake catalog used in map I-2812: 1. CAUTIONS: This earthquake catalog was assembled for use in a poster (Wheeler and others, 2003) that is intended to inform the general public. The catalog was not designed for scientific or engineering use, or for hazard assessment, and it should not be used for these purposes. Wheeler (2003) described the procedures used to assemble the catalog, and you should examine that report before using the earthquake catalog. This file was written under the assumption that you have read Wheeler (2003) to determine whether this catalog is suitable for whatever use you might wish to make of it. 2. DESCRIPTION OF COLUMNS: The seven columns of the earthquake catalog contain (1) year, month, and day, (2) hour, minute, and second in Universal Coordinated Time, (3) longitude in decimal degrees west, (4) latitude in decimal degrees north, (5) magnitude, generally m(bLg) or an estimate of it, (6) postal abbreviation of the State in which the earthquake occurred, and (7) the source or sources of the record. 3. ABBREVIATIONS USED IN "SOURCE(S)" COLUMN: Most of the records for individual earthquakes were taken from one or another of the standard, Web-searchable, earthquake catalogs that are used in the central U.S. The "Source(s)" column lists the abbreviation of the source catalog for each record. Wheeler (2003) defined the abbreviations and described the source catalogs. In addition, several records contain published moment magnitudes that were computed in special studies. The source publication of a moment magnitude is identified in the "Source(s)" column by one of the abbreviations defined in the following list. An asterisk following a comma at the end of the "Source(s)" field indicates that the moment magnitude was also compiled by Johnston (1996). CC&J97 – Chiu, S.-C., Chiu, J.-M., and Johnston, A.C., 1997, Seismicity of the southeastern margin of the Reelfoot rift, central United States: Seismological Research Letters, v. 68, no. 5, p. 785-796. H79 – Herrmann, R.B., 1979, Surface wave focal mechanisms for eastern North American earthquakes with tectonic implications: Journal of Geophysical Research, v. 84, no. B7, p. 3543-3552. H&A97 – Herrmann, R.B., and Ammon, C.J., 1997, Faulting parameters of earthquakes in the New Madrid, Missouri, region: Engineering Geology, v. 46, p. 299-311. J96III – Johnston, A.C., 1996, Seismic moment assessment of earthquakes in stable continental regions - III. New Madrid 1811-1812, Charleston 1886 and Lisbon 1755: Geophysical Journal International, v. 126, p. 314-344. K03 -- Kim, W.-Y., 2003, The 18 June 2002 Caborn, Indiana, earthquake: Reactivation of ancient rift in the Wabash Valley seismic zone?: Bulletin of the Seismological Society of America, v. 93, no. 5, p. 2201-2211. N&H92 – Nguyen, B.V., and Herrmann, R.B., 1992, Determination of source parameters for central and eastern North American earthquakes (1982-1986): Seismological Research Letters, v. 63, no. 4, p. 567-586. S86 -- Somerville, P., 1986, Source-scaling relations of eastern North American earthquakes: Electric Power Research Institute Final Report NP-4789, 186 p. Setal91 – Street, R., Zekulin, A., and Harris, J., 1991, The Meade County, Kentucky, earthquakes of January and March 1990: Seismological Research Letters, v. 62, no. 2, p. 105-111. Tetal89 – Taylor, K.B., Herrmann, R.B., Hamburger, M.W., Pavlis, G.L., Johnston, A., Langer, C., and Lam, C., 1989, The southern Illinois earthquake of 10 June 1987: Seismological Research Letters, v. 60, no. 3, p. 101-110. The entire record for the June 18, 2002 earthquake near Evansville, Indiana, was taken from Kim (2003). This publication is not listed in Table 2 of Wheeler (2003) because the report of Kim was not yet published, although W.-Y. Kim generously supplied a preprint for use in preparation of the catalog and poster. 4. REFERENCES CITED IN THIS FILE: Johnston, A.C., 1996, Seismic moment assessment of earthquakes in stable continental regions - I. Instrumental seismicity: Geophysical Journal International, v. 126, p. 381-414. Kim, W.-Y., 2003, The 18 June 2002 Caborn, Indiana, earthquake: Reactivation of ancient rift in the Wabash Valley seismic zone?: Bulletin of the Seismological Society of America, v. 93, no. 5, p. 2201-2211. Wheeler, R.L., 2003, Earthquakes in the central United States, 1795-2003 -- Construction of the earthquake catalog for an outreach map: U.S. Geological Survey Open-File Report 03-232, 15 p. Wheeler, R.L., Omdahl, E.M., Dart, R.L., Wilkerson, G.D., and Bradford, R.H., 2003, Earthquakes in the central United States -- 1699-2002: U.S. Geological Survey Geologic Investigations Series I-2812, 1 sheet, scale 1:1,125,000.