Local Magnitude and Anomalous Amplitude Distance Decay in the Eastern Tennessee Seismic Zone

Research Article| April 08, 2015 Local Magnitude and Anomalous Amplitude Distance Decay in the Eastern Tennessee Seismic Zone Blaine M. Bockholt; Blaine M. Bockholt Center for Earthquake Research and Information, University of Memphis, 3890 Central Avenue, Memphis, Tennessee 38152 U.S.A.bbckholt@memphis.edu Search for other works by this author on: GSW Google Scholar Charles A. Langston; Charles A. Langston Center for Earthquake Research and Information, University of Memphis, 3890 Central Avenue, Memphis, Tennessee 38152 U.S.A.bbckholt@memphis.edu Search for other works by this author on: GSW Google Scholar Mitch Withers Mitch Withers Center for Earthquake Research and Information, University of Memphis, 3890 Central Avenue, Memphis, Tennessee 38152 U.S.A.bbckholt@memphis.edu Search for other works by this author on: GSW Google Scholar Author and Article Information Blaine M. Bockholt Center for Earthquake Research and Information, University of Memphis, 3890 Central Avenue, Memphis, Tennessee 38152 U.S.A.bbckholt@memphis.edu Charles A. Langston Center for Earthquake Research and Information, University of Memphis, 3890 Central Avenue, Memphis, Tennessee 38152 U.S.A.bbckholt@memphis.edu Mitch Withers Center for Earthquake Research and Information, University of Memphis, 3890 Central Avenue, Memphis, Tennessee 38152 U.S.A.bbckholt@memphis.edu Publisher: Seismological Society of America First Online: 14 Jul 2017 Online ISSN: 1938-2057 Print ISSN: 0895-0695 © 2015 by the Seismological Society of America Seismological Research Letters (2015) 86 (3): 1040–1050. https://doi.org/10.1785/0220140201 Article history First Online: 14 Jul 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Tools Icon Tools Get Permissions Search Site Citation Blaine M. Bockholt, Charles A. Langston, Mitch Withers; Local Magnitude and Anomalous Amplitude Distance Decay in the Eastern Tennessee Seismic Zone. Seismological Research Letters 2015;; 86 (3): 1040–1050. doi: https://doi.org/10.1785/0220140201 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietySeismological Research Letters Search Advanced Search ABSTRACT Seismic waveforms from the Eastern Tennessee Seismic Network are corrected to the nominal Wood–Anderson (WA) torsion seismometer to obtain a total of 11,905 maximum trace amplitudes from 690 events seen on 50 different horizontal components to determine a local magnitude scale for the Eastern Tennessee Seismic Zone (ETSZ). We use the following distance‐correction function −log10(A0)=0.538(r/17)−0.0002516(r−17)+2.0, in which A0 is the maximum amplitude measured in millimeters and r is the hypocentral distance measured in kilometers; this better agrees with reported moment magnitudes for larger events in the ETSZ. Using the normal 100 km distance for ML normalization severely overestimates ML, and we therefore chose to adopt the 17 km normalization technique. The −log10(A0) is very flat at distances >200 km, suggesting unusually low distance attenuation at local and near‐regional distances from the ETSZ. The WA response reported by the International Association of Seismology and Physics of the Earth’s Interior to the nominal response shows no significant difference in the distance‐dependent factor for the logA0 term, although the revised response consistently yields ML values that are 0.1 lower than those found using the nominal response. The b‐values for the currently reported duration magnitude are lower than the b‐values obtained using the newly calculated ML scale. The relationship between ML and MD can be expressed as ML=0.68093MD+0.64603. The catalog of events used in this study is complete for ML>1.3. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.