DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY Historical Seismicity in the Southern Appalachian Seismic Zone by D. J. Reinbold and A. C. Johnston* Open-File Report 87-433 U.S. Geological Survey Contract Report This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards (and stratigraphic nomenclature). Any use of.trade names is for descriptive purposes only and does not imply endorsement by the USGS. *Tennessee Earthquake Information Center Memphis State University Memphis/ Tennessee HISTORICAL SEISMICITY IN THE SOUTHERN APPALACHIAN SEISMIC ZONE ABSTRACT This report presents the result of an effort to compile as complete and accurate an historical earthquake catalog as is possible for the Southern Appalachian Seismic Zone (SASZ). This catalog is unique in that substantially all of the supporting documentation is provided as an integral part of the history. Consistent and methodical interpretation of intensity and location is maintained throughout. New formulae developed by Sibol and others (1986) for converting epicentral intensity and felt area to magnitude are used. The equation relating mb to lo and felt area is thought to provide the best estimates yet of magnitudes for non-instrumental earthquakes in the SASZ. Additionally, depth of focus estimates are made. Four events mb >5.0 are listed among the 166 events that comprise this catalog. The largest event is the Modified Mercalli intensity VIII, 1897 Giles County, Virginia earthquake, mb = 5.6 (this study). Recurrence curves are plotted for both intensity and magnitude data. These suggest that an intensity VII (mb X5.0) should be expected roughly every 20-40 years. The last events in the SASZ generating intensity VII occurred in 1916. INTRODUCTION This report presents the results of a new study of the historical seismicity of an area of the sOUTHEAStern United States known as the Southern Appalachian Seismic Zone (SASZ). It is intended to complement current and ongoing instrumental studies that began in 1977 and therefore provide an improved data base for seismic hazard assessment of the region. The Southern Appalachian Seismic Network (SARSN) achieved a locational capability in mid-1981, and the network was substantially completed by the end of 1983. Johnston and others (1985) reported more than 100 new or relocated hypocenters obtained from the initial 2 1/2 years of operation; through 1985, there have been more than 230 earthquakes located (TEIC Bulletin, 1986). Although these data are of high quality and are accumulating rapidly, a significantly longer time is needed to make judgements about recurrence intervals and maximum possible earthquakes. Therefore, a reliance on historical (non-instrumental) seismicity is mandated. Bollinger (1975) published a comprehensive seismic catalog for the entire southeastern United States which has been the key reference for historical seismicity in this area for a decade. This study focuses on the Southern Appalachian Seismic Zone (SASZ), which is a relatively small part of Bollinger's area and contains the area monitored by SARSN. Its purpose was to compile as complete and accurate a catalog of earthquakes as is possible from historical data. This was accomplished by adding significantly to the data base used by Bollinger from both published (e.g., journal articles, contemporary newspapers) and non-published (e.g., personal files) sources. The first catalog entry is November 1776, and entries extends through 1976, the year preceding the first published instrumental data bulletin (SEUSSN Bulletin, Bollinger and others, 1978-1984). Only events that were reported as being felt are included. Contributions of data from 176 different published papers and/or reports and more than 100 different newspapers were used to obtain a working data base in excess of 400 events for the SASZ and surrounding area (exclusive of Charleston, SC). It was necessary to compile a list of events for a wide area around the SASZ in addition to those within. This was done so that a felt report recorded from a location within the study area that may have been the result of a large, distant earthquake could be properly associated; delineation of felt areas for events originating within the SASZ also requires felt information from outside the zone. Evaluation and interpretation of the volumes of data for these events resulted in a catalog of 166 earthquakes that originated and were felt in the SASZ. (Most events identified as foreshocks or aftershocks are not listed separately.) Location, epicentral intensity (lo), and felt area are the critical interpreted parameters. Magnitudes (mb) and depth of focus estimates are additional derived parameters, using techniques described later in the report. Table 1 is a summary listing of source information for all events of this compilation; felt area maps for 94 of the events can be found in Appendix A. A catalog documenting all relevant data for each event constitutes Appendix B. The Appendices are bound separately from this report. SOUTHERN APPALACHIAN SEISMIC ZONE (SASZ) The Southern Appalachian Seismic Zone (SASZ) has been a source of moderate seismic energy release for at least 200 years. The area referred to in this study is essentially the same as that delineated by Bollinger (1973); its boundaries are shown in Figure 1. The SASZ lies primarily in the Valley and Ridge and Blue Ridge physiographic provinces of eastern Tennessee and Western North Carolina and includes parts of the states of of Virginia, Vest Virginia, Kentucky, South Carolina, Georgia, and Alabama. The boundaries extend from the Table 1. Historical Earthquakes in the Southern Appalachian Seismic Zone: 1776 through 1976 DATE TIME NLAT WLON LOCALITY FELT AREA lo mb (km2) 1776 Noy 5 P-m. 35.4 83.0 Richland Balsam, NC IV 3.1 III 1825 36.2 81.2 Wilkesboro, NC 2.8 1827 May 11 P-m. 36.2 81.2 Wilkesboro, NC 1,800 IV 3.1 14 1829 35.2 83.8 Andrews, NC III 1836 May 7 36.0 83.9 Knoxville, TN 2.8 1844 Jun 35.4 83.4 Bryson City, NC 1844 Nov 28 13:00 35.8 84.0 Maryville, TN 2,900 VI 3.7 6 1848 35.5 82.2 Stone Mt. , NC 1851 Aug 11 01:55 35.6 82.6 Asheville, NC V 3.5 1852 Apr 29 18:00 36.7 82.0 Abingdon, VA 274,000 VII 5.0 13 III 1852 May 3 08:00 36.7 82.0 Abingdon, VA 2.8 III 1852 Sep 18 36.7 82.0 Abingdon, VA 2.8 III 1854 Feb 13 00:00 37.2 83.8 Manchester, KY 2.8 III 1854 Nov 22 21:00 37.1 81.5 Tazewell, VA 2.8 III 1857 Dec 11 03:00 37.8 80.4 Levisburg, WV 2.8 1859 Mar 22 37.1 81.5 Jef fersonville, VA IV 3.1 1861 Aug 31 10:22 36.2 81.2 Wilkesboro, NC 586,000 VI 4.9 23 1874 Feb 22 35.5 82.2 Stone Mt., NC III 1875 Nov 12 08:00 36.0 83.9 Knoxville, TN 2.8 1876 Jan 23 35.5 82. 2 Stone Mt. , NC III 1876 Dec 21 15:30 37.0 81. 1 Wytheville, VA 2.8 III 1877 Apr 26 22:00 35.2 83.4 Franklin, NC 2.8 III 1877 May 25 36.0 83.9 Knoxville, TN 2.8 1877 Oct 9 01:00 35.3 82.5 Hendersonville, NC 1,200 IV 3.1 13 1877 Nov 16 08:38 36.0 83.9 Knoxville, TN 3,200 IV 3.2 15 III 1878 Nov 23 15:00 35.1 84.0 Murphy, NC 2.8 1880 Jan 28 35.5 82.2 Stone Mt., NC IV 3.1 III 1882 Oct 15 17:30 35.1 84.0 Murphy, NC 2.8 1884 Jan 35.5 82.2 Stone Mt. , NC II 1884 Apr 30 11:46 35.2 84. 2 Ogreeta, NC 2.6 1884 Summer 35.7 82.5 Elk Mt., NC IV 3.1 1884 Aug 25 00:45 36.0 83.9 Knoxville, TN IV 3.1 1885 Feb 2 12:10 37.0 81. 1 Wytheville, VA IV 3.1 1885 Aug 13 13:00 36.1 81. 7 Blowing Rock, NC 500 IV 2.9 11 III 1886 Sep 25 02:56 37.0 81. 1 Wytheville, VA 2.8 III 1888 Mar 17 36.3 82.5 Jonesboro, TN 2.8 III 1889 Sep 28 P-m. 35.1 84.6 Parksville, TN 2.8 1892 Dec 2 08:00 35.0 85.3 Chattanooga, TN 1,900 V 3.4 9 1897 May 3 17:18 37.1 80.6 Radford, VA 47,000 VI 4.2 12 1897 May 31 19:00 37.3 80.7 Pearisburg, VA 725,000 VIII 5.6 13 1897 Jun 29 04:00 37.3 80. 7 Pearisburg, VA 12,000 V 3.7 13 1897 Sep 3 11:00 37.3 80. 7 Pearisburg, VA 2,000 IV 3.2 14 1897 Oct 22 03:25 37.3 80.0 Salem, VA 36,000 V 3.9 16 1898 Feb 5 20:02 37.1 80. 7 Dublin, VA 50,000 VI 4.3 12 1898 Nov 25 20:10 37.1 80.6 East Radford, VA 92,000 V 4.2 21 1899 Feb 13 09:30 37.1 81.5 Tazewell, VA 115,000 V 4.2 22 1902 May 18 04:00 37.3 80. 7 Pearisburg, VA V 3.5 1902 May 29 07:30 35.0 85.3 Chattanooga, TN IV 3.1 DATE TIME NLAT VLON LOCALITY FELT AREA lo mb (km2) 1902 Oct 18 22:00 35.3 85.7 Tracy City, TN[ V 3.5 11 1904 Mar 5 00:30 35.8 84.0 Maryville, TN 2,500 IV 3.2 14 1905 Apr 29 37.3 79.5 Bedford, VA III 2.8 1909 Oct 8 10:00 34.8 85.0 Dalton, GA 900 III 2.9 20 1911 Apr 22 03:00 35.3 82.5 Hendersonville,i, NC 3,900 IV 3.3 16 1913 Mar 13 05:00 34.5 85.0 Calhoun, GA III 2.8 1913 Mar 28 22:50 36.0 83.9 Knoxville, TN 4,000 VI 1913 Apr 17 17:30 35.5 84.4 Madisonville, TN 6,500 V 3.6 11 1913 May 2 07:00 35.5 84.4 Madisonville, TN III 2.8 1913 Aug 3 17:45 36.0 83.9 Knoxville, TN III 2.8 1914 Jan 24 04:24 35.6 84.5 Sveetvater, TNf 5,900 IV 3.4 17 1915 Jan 14 09:20 36.6 82.2 Bristol, TN IV 3.1 1915 Oct 29 05:45 35.6 82.6 Asheville, NC 700 V 3.2 7 1916 Feb 21 22:39 35.5 83.0 Waynesville, 1C 458,000 VII 5.1 15 1916 Aug 26 19:35 35.9 81.2 Taylorsville, NC 7,100 V 3.6 11 1916 Oct 18 22:04 33.5 86.7 Irondale, AL 358,000 VII 5.1 14 1916 Oct 22 33.5 86.8 Birmingham, AL III 2.8 i 1916 Nov 4 12:15 33.5 86.8 Birmingham, AL V 3.5 j 1917 Jan 2 10:30 36. 1 83.7 Mascot, TN IV 3.1 1917 Jan 25 22:15 36. 1 83.5 Jefferson City' , TN III 2.8 1917 Mar 5 03:07 36.0 83.9 Knoxville, TN III 2.8 1917 Mar 27 21:00 36. 1 83.5 Jefferson City,', TN V 3.5 1917 Apr 19 37.0 81. 1 Wytheville, VA III 2.8 L 1917 Jun 21 36.0 83.9 Knoxville, TN IV 3.1 1918 Jan 17 16:45 36.0 83.9 Knoxville, TN 2,300 IV 3.2 14 'N 1918 Jun 22 00:59 35.8 84.3 Lenoir City, ' 5,800 IV 3.4 17 1920 Dec 24 08:30 35.8 84.7 Glen Alice, TNI 2,600 V 3.4 9 1921 Jul 15 36.7 82. 3 Mendota, VA VI 4.0 1921 Dec 15 14:20 35.9 84.5 Kingston, TN 2,700 V 3.4 9 1922 Mar 30 22:20 36.6 82.5 Arcadia, TN IV 3.1 1923 Oct 18 19:30 35.3 82.5 Hendersonville,>., NC IV 3.1 1924 Oct 20 08:30 34.9 82.7 Pickens, SC 87,000 VI 4.4 14 1924 Nov 13 05:30 36.6 82.2 Bristol, VA IV 3.1 1924 Dec 25 04:30 37.3 79.9 Roanoke, VA V 3.5 1926 Jul 8 09:50 35.9 82. 1 Spruce Pine, 1C VI 4.0 1927 Jun 16 13:00 34.7 86.0 Scottsboro, AL 3,000 V 3.4 9 j 1927 Jul 20 09:58 36.0 83.9 Knoxville, TN V 3.5 1927 Oct 8 13:58 35.0 85.3 Chattanoga, TNI 2,000 V 3.4 9 1928 Nov 3 04:04 35.9 82.8 Hot Springs, : 1C 187,000 VII 4.9 12 1928 Nov 20 03:45 35.9 82.8 Hot Springs, : 1C 4,700 IV 3.3 16 1930 Aug 30 10:28 35.8 84.3 Lenoir City, ' :N 4,000 V 3.5 10 1930 Oct 16 21:50 36.0 83.9 Knoxville, TN V 3.5 1931 May 5 13:18 33.5 86.8 Birmingham, ALj 33,000 V 3.9 16 1935 Jan 1 08: 15 35.2 83.7 Topton, NC 15,000 VI 4.0 9 1936 Jan 1 08:00 34.9 84. 3 Blue Ridge, GAL 4,800 III 3.2 27 1938 Mar 31 10:10 35.5 84.0 Tapoco, NC 14,500 V 3.7 13 1939 May 5 03:45 33.7 85.8 Anniston, AL 2,000 V 3.4 9 1939 Jun 24 11:27 34.7 86.6 Huntsville, ALj 6,400 IV 3.4 17 1940 Oct 19 05:55 35.0 85. 1 Ryall Springs, TN 3,200 V 3.4 10 1940 Dec 25 06:50 35.9 82.8 Hot Springs, 1C 17,000 V 3.8 14 1941 Mar 4 06:15 35.9 83.9 Rockford, TN IV 3.1 1941 May 10 11:12 35.6 82.6 Asheville, NC IV 3.1 1941 Sep 8 09:45 35.0 85. 3 Chattanooga, :N 1,100 V 3.3 8 1945 Jun 14 03:25 35.2 84.9 Cleveland, TN 8,100 V 3.6 12 DATE TIME NLAT WLON LOCALITY FELT AREA lo mb (km2) 1946 Apr 7 06:00 35.2 84.9 Cleveland, TN IV 3.1 1947 Jun 6 12:55 36.0 83.9 Knoxville, TN IV 3.1 1947 Dec 28 00:05 35.0 85.1 Ryall Springs, TN 3,000 IV 3.2 15 1948 Feb 10 00:04 36.4 84.0 Wells Springs, TN 1,700 VI 3.6 6 1949 Sep 17 09:30 36.8 83.0 Pennington Gap, VA 1,700 IV 3.1 13 1950 Jun 19 04: 19 35.5 84.0 Tapoco, NC 9,700 V 3.6 12 1952 Feb 6 16: 12 33.5 86.8 Birmingham, AL IV 3.1 1952 Jun 11 20:20 36.3 82.3 Johnson City, TN V 3.5 1953 Nov 10 14:53 36.0 83.9 Knoxville, TN 700 IV 3.0 12 1953 Dec 5 13:45 36.0 83.9 Knoxville, TN 660 IV 3.0 12 1954 Jan 1 01:30 37.2 83.2 Hazard, KY 400 IV 2.9 11 1954 Jan 2 02:25 36.6 83.7 Middlesboro, KY 34,000 VI 4.2 11 1954 Jan 14 p.m. 36.0 83.9 Knoxville, TN IV 3.1 1954 Jan 23 01:00 35.3 84.5 Etowah, TN 500 IV 2.9 11 1955 Jan 6 20:30 36.6 82.2 Bristol, TN IV 3.1 1955 Jan 12 17:25 35.8 84.0 Maryville, TN 300 IV 2.9 10 1955 Jan 25 19:32 35.9 83.9 Rockford, TN 1,800 V 3.3 9 1955 Sep 28 07:02 36.6 81.3 Piney Creek, NC 3,500 VI 3.7 6 1956 Sep 7 13:36 36.2 83.8 Maynardville, TN 30,000 VI 4.1 10 1957 Jan 25 18: 15 36.6 83.7 Middlesboro, KY IV 3.1 1957 Apr 23 09:24 33.5 86.8 Birmingham, AL 53,000 VI 4.3 12 1957 May 13 14:25 35.8 82.0 Sevier, NC 20,500 VI 4.1 9 1957 Jun 23 06:34 35.9 84.1 Concord, TN 1,500 V 3.3 8 1957 Jul 2 09:33 35.6 82.6 Asheville, NC 22,000 VI 4.1 10 III 1957 Nov 7 36.0 84.0 Powell, TN 2.8 1957 Nov 24 20:06 35.8 83.1 Hartford, TN 12,000 VI 3.9 8 1958 May 16 22:30 35.6 82.6 Asheville, NC IV 3.1 1959 Apr 23 20:59 37.3 80.6 Eggleston, VA 4,400 VI 3.7 7 1959 Jun 13 01:00 35.4 84.3 Tellico Plains, TN 3,200 IV 3.2 15 1959 Jul 7 23: 17 37.3 80.7 Pearisburg, VA IV 3.1 1959 Aug 12 18:06 34.8 86.6 Meridianville, AL 10,000 VI 3.9 8 1959 Aug 21 17:20 37.3 80.7 Pearisburg, VA 600 IV 3.0 11 1960 Jan 3 07:30 35.9 82.1 Spruce Pine, NC 1,500 IV 3.1 13 1960 Feb 9 14:00 35.4 82.4 Edneyville, NC 260 V 3.1 6 1960 Apr 15 10: 10 35.8 84.0 Alcoa, TN 3,900 V 3.5 10 1963 Jan 17 11:40 37.3 80.1 Salem, VA 2,600 V 3.4 9 1963 Oct 28 22:39 36.6 81.0 Ennice, NC 5,900 V 3.6 11 1964 Jan 20 13: 38 35.9 82.3 Pensacola, NC 600 IV 3.0 11 1964 Feb 18 10: 31 34.5 85.5 Menlo, GA 2,100 V 3.4 9 III 1964 Jul 28 19:45 36.0 84.0 Inskip, TN 2.8 III 1964 Oct 13 16: 30 36.0 83.9 Knoxville, TN 2.8 1966 Aug 24 06:00 35.8 84.0 Alcoa, TN 800 IV 3.0 12 1968 Mar 8 05:38 37.3 80.8 Narrows, VA 10,000 V 3.7 12 1969 Jul 13 21:51 36.0 83.9 Knoxville, TN 55,000 VI 4.3 12 III 1969 Jul 24 18: 10 36.0 83.9 Knoxville, TN 2.8 1969 Nov 20 01:00 37.4 80.9 Elgood, WV 322,000 VI 4.8 20 1969 Dec 13 10:20 35.2 83. 1 Glenville, NC 11,000 V 3.7 12 1970 Aug 11 06: 14 38.4 81.8 St. Albans, WV 3,000 IV 3.2 15 1970 Sep 10 01:41 36.1 81.7 Blowing Rock, NC 14,000 V 3.7 13 1971 Jul 13 03:03 36.0 84.3 Oak Ridge, TN 5,800 IV 3.4 17 1971 Oct 9 16:44 35.7 83.5 Gatlinburg, TN 8,500 V 3.6 12 1973 Oct 30 22.59 35.8 84.0 Alcoa, TN 6,300 V 3.6 11 1973 Nov 30 07:49 35.8 84.0 Alcoa, TN 98,000 VI 4.4 14 DATE TIME NLAT VLON LOCALITY FELT AREA lo mb h (km2) ~ ~~~ 1974 May 30 21:29 37.3 80.6 Pembroke, VA 21,000 V 3.8 14 1975 Mar 7 12:45 37.3 80.7 Pearisburg, VA 1,300 III 2.9 21 1975 May 2 16:23 36.0 84.6 Oakdale, TN III 2.8 1975 May 14 23:03 36.0 84.3 Oak Ridge, TN III 2.8 1975 Aug 29 04:23 33.7 86.7 Palmerdale, AL 57,000 VI 4.3 12 1975 Nov 11 08:11 37.3 80.7 Ripplemead, VA 1,100 V 3.3 8 1975 Nov 25 15:18 34.9 83.0 Salem, SC 6,100 IV 3.4 17 1976 Jan 19 06:31 36.9 83.9 Barbourville, KY VI 4.0 1976 Feb 4 19:54 35.0 84.7 Conasanga, TN 6,000 VI 3.8 7 1976 Jun 19 05:54 37.4 81.6 Wilcoe, WV 1,000 V 3.2 8 1976 Sep 13 18:55 36.5 80.6 Toast, NC 18,000 VI 4.0 9 7 north near Roanoke in southwestern Virginia southwest to central Alabama, where the Coastal Plain sediments begin to overlap. Northwest to southeast, the SASZ is bounded by the Cumberland escarpment which marks the approximate westward extent of the folded Appalachians and the Brevard zone which separates the Blue Ridge from the Piedmont. Long, narrow ridges, generally striking NE-SW, characterize the Valley and Ridge province which is underlain by Cambrian to Pennsylvanian-aged sedimentary rocks that have been folded and faulted. The Blue Ridge is an allochthonous mass of rugged peaks dominantly composed of metamorphic and igneous rocks which range in age from Precambrian to Cambrian and which overthrust Paleozoic and Precambrian sedimentary strata. Thin thrust sheets of large dimensions typify the structure of the southern Appalachians [e.g., Cook and others (1983)]. CATALOG DESCRIPTION A base data file was established through the synthesis of the data from primary references, original sources of data were tracked, and archival newspaper files searched. The original primary reference list included some additional references from the area surrounding the SASZ, e.g., the rest of the Southeast, the New Madrid seismic zone, Illinois, Indiana, Ohio, etc. Data from over 400 events were compiled and evaluated to produce the present catalog of 166 events. The complete documentation for each of the SASZ events as contained in Appendix B, Data Documentation, was used for the evaluation and interpretation of the intensity data, the preparation of felt area maps (which were plotted when two or more localities "felt" an event), and determination of epicenters. Computational parameters, e.g., magnitude and depth of focus, depend on the interpreted data and were obtained subsequent to completion of Appendix B. The following sections contain: (1) a discussion of the primary references 8 for the SASZ, (2) a description of the catalog format, and (3) a discussion of intensity and location determination. Primary References The following 10 references comprise the primary reference list for the Southern Appalachian Seismic Zone: the number in brackets indicates the reference number in the catalog bibliography of Appendix B. TVA [380] The TVA catalog referenced is an unpublished compilation of data on earthquakes east of 87° west longitude and south of 39 north latitude; A significant part of the data presented in this study is data collected for that catalog which includes Berlen C. Moneymaker's personal files. It covers the complete area and period of present study; Modified Mercalli intensities are used. USGS [390] This is a general reference that includes any of a number of earthquake compilations published by the U.S. Coast and Geodetic Survey, NOAA, or the U.S. Geological Survey (seismological investigation was assigned by law to the U.S. C&GS in 1925). It includes several editions of the publication, Earthquake History of the United States - these publications list only events with intensities greater than, or equal to V; although the C&GS adopted the Wood-Neumann measure of earthquake intensity in 1931, intensities were reported according to the Rossi-Forel Scale through 1947. Several versions of EQHUS are included, because with time, additions, deletions, changes, and corrections altered the data from one volume to the next. Also included under this reference are the publications United States Earthquakes published annually