PACKET RADIO: Siesmic Technospeak

Steve Wolf, W8IZ@W8IZ


(This text from the W8IZ packet radio bulletin

board. It's formatted to fit a 80 character screen.)


MSG # TR  SIZE TO     FROM   @BBS   DATE    TITLE
42688 B$  6016 ALL    WB3CSY ALLUS  901123 Seismic Data Explained
     EXPLANATION OF ABBREVIATIONS AND SYMBOLS APPEARING IN THIS LISTING
 
Abbreviations in Heading:
 
UTC TIME - Origin time in Coordinated Universal Time.
 HRMNSEC - Hour, minute, second.
     LAT - Geographic latitude in degrees.
    LONG - Geographic longitude in degrees.
     DEP - Depth in kilometers.
 GS MAGS - Magnitudes computed by USGS/NEIS.
      MB - Body wave magnitude.
     Msz - Vertical surface wave magnitude.
      SD - Standard Deviation from the arithmetic mean of residuals.
STA USED - Number of stations reporting P or PKP phases used in computation.
 
Symbols Following Origin Time:
 
 &  Indicates that parameters of the hypocenter were supplied or determined by
    a computational procedure not normally used by NEIS.  The source or nature
    of the determination is indicated by a 2 to 5 letter code enclosed by angle
    brackets and appearing in the first line of comments.  A "-P" appended to
    the code indicates that the computation is preliminary.  These codes are
    included in the list of abbreviations below.
 
 %  Indicates a single network solution.  A non-furnished hypocenter has been
    computed using data reported by a single network of stations for which the
    date and/or origin time cannot be confirmed from seismograms available to
    a NEIS analyst.  The geometric mean of the semi-major and semi-minor axes
    of the horizontal 90% confidence ellipse is less than or equal to 16.0 km.
 
 *  Indicates a less reliable solution.  In general, the geometric mean of the
    semi-major and semi-minor axes of the horizontal 90% confidence ellipse is
    greater than 8.5 km and less than or equal to 16.0 km.
 
 ?  Indiates a poor solution, published for completeness of the catalogue.  In
    general, the geometric mean of the semi-major and semi-minor axes of the
    horizontal 90% confidence ellipse is greater than 16.0 km.  This includes
    a poor solution computed using data reported by a single network.
 
 Q  Indicates a preliminary solution obtained from the NEIC Earthquake Early
    Alerting Service program "Quick-quake."
 
    The lack of any symbol indicates that the geometric mean of the semi-major
    and semi-minor axes of the horizontal 90% confidence ellipse is less than
    or equal to 8.5 km.
 
Symbols Following Depth:
 
N  Indicates depth was restrained at 33 km for earthquakes whose character on
   seismograms indicate a shallow focus but whose depth is not satisfactorily
   determined by the data.
 
D  Indicates depth was restrained by the computer program based on 2 or more
   compatible pP phases and/or unidentified secondary arrivals used as pP.
 
G  Indicates the depth was restrained by a geophysicist.
 
*  Indicates a less well-constrained free depth.  The 90% marginal confidence
   interval on depth is greater than 8.5 km and less than or equal to 16.0 km.
 
?  Indicates a poorly-constrained free depth.  The 90% marginal confidence
   interval on depth is greater than 16.0 km.
 
   The lack of any symbol indicates that the 90% marginal confidence interval
   on depth is less than or equal to 8.5 km, or that a contributed hypocenter
   was computed with a free depth, regardless of the size of the confidence
   interval.
 
Symbols and Abbreviations Used in Comments:
 
     BLA  Virginia Polytechnic Institute and State University, Blacksburg.
     BRK  University of California, Berkeley.
      CL  Coda length magnitude.
     DOE  U.S. Department of Energy.
    ERDA  U.S. Energy Research and Development Administration.
   EXPLO  Some or all parameters of explosion (controlled or accidental)
          supplied by any group or individual other than ERDA or its successor
          organizations.
     GLD  U.S. Geological Survey, Golden, Colorado (other than NEIS).
      GS  U.S. Geological Survey, Menlo Park, California
     HVO  Hawaiian Volcano Observatory.
     JMA  Japan Meteorological Agency (generally used to indicate 7-point
          Japanese Intensity Scale).
     LDG  Laboratoire de Detection et de Geophysique, Montrouge, France.
   MACRO  Hypocenter based upon macroseismic information.
      MD  Duration magnitude.
    NEIS  U.S. Geological Survey, National Earthquake Information Service,
          Golden, Colorado
     OTT  Earth Physics Branch, Ottawa, Canada.
     PAL  Columbia University, Lamont-Doherty Observatory, Palisades, New York.
     PAS  California Institute of Technology, Pasadena.
     PGC  Pacific Geoscience Centre, Sidney, British Columbia, Canada.
     PMR  Alaska Tsunami Warning Center, Palmer, Alaska.
      RF  Rossi-Forel Intensity Scale.
     SEA  University of Washington, Seattle.
     SLC  University of Utah, Salt Lake City.
     SLM  St. Louis University, Missouri.
    TEIC  Tennessee Earthquake Information Center, Memphis.
     TUL  Oklahoma Geological Survey, Leonard.
     WES  Weston Observatory, Massachusetts.
 
Roman     Used to indicate intensity (when not followed by RF or JMA they refer
Numerals          c 
      -P  Supplied hypocenter is a preliminary computation.
 
          Any additional 3 to 5 letter codes enclosed i 
 
For an explanation of other topics such as magnitude formulas, travel time
tables or intensity scales, please refer to the latest January or July issue
of the publication "Preliminary Determination . 

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