
                              FORMAT OF USGS/NEIC EHDF FILE


Char. Pos.       Description
 1-2             "GS"
 3-4             blank
 5-12            EVENT DATE in YYYYMMDD format
13-20            ORIGIN TIME in HHMMSSTH format
21-26            LATITUDE
        21-25        geographic latitude value in f5.3 format (DDTHT)
        26           N or S
27-33            LONGITUDE
        27-32        geographic longitude value in f6.3 format (DDDTHT)
        33           E or W
34-40            DEPTH
        34-37        depth value in f4.1 format (NNNT)
        38           depth control or quality indicator (D, G, N, * or ?)
        39-40        number of depth phases used (i2 - shows 99 if >=99)
41-47            HYPOCENTER QUALITY INDICATORS
        41-43        number of P or PKP arrivals used in solution (i3 format)
        44-46        standard deviation in f3.2 format (NTH)
        47           authority/quality indicator (&, *, % or ?)
48-51            GS AVERAGE MB
        48-49        MB value in f2.1 format (NT)
        50-51        number of amplitudes used (i2 - shows 99 if >=99)
52-56            GS AVERAGE MS
        52-53        Ms value in f2.1 format (NT)
        54-55        number of amplitudes used (i2 - shows 99 if >=99)
        56           component (currently only Z)
57-66            CONTRIBUTED MAGNITUDE NUMBER 1
        57-59        magnitude value in f3.2 format (NTH - with H usually 0)
        60-61        type (MW, ME, MS, MB, ML, LG, RG, MD or CL)
        62-66        contributor (left justified a5 format, blank if source
                         is NEIS)
67-76            CONTRIBUTED MAGNITUDE NUMBER 2
        67-69        magnitude value in f3.2 format (NTH - with H usually 0)
        70-71        type (MW, ME, MS, MB, ML, LG, RG, MD, CL or MG)
        72-76        contributor (left justified a5 format, blank if source
                         is NEIS)
77-79            FLINN-ENGDAHL GEOGRAPHIC REGION NUMBER (in i3 format)
80               MAXIMUM INTENSITY (a1 format - 1-9, X, E or T)
81-92            FLAGS
        81           macroseismic (H=heard, F=felt, D=damage, C=casualties)
        82           moment tensor (any source) published in monthly listing (M)
        83           isoseismal/intensity map (P = PDE or Monthly Listing or 
                         U = U.S. Earthquakes)
        84           GS fault plane solution (F)
        85           IDE event (X)
        86           diastrophic phenomena (U = uplift, S = subsidence, 
                         F = faulting, 3 = U & S, 4 = U & F, 5 = S & F, 6 = all)
        87           tsunami (T or Q)
        88           seiche (S or Q)
        89           volcanism (V)
        90           non-tectonic source (E = explosion, I = collapse, 
                         C = coalbump or rockburst in coal mine, R = rockburst,
                         M = meteoritic source)
        91           guided waves in atmosphere/ocean (T = t wave, 
                         A = acoustic wave, G = gravity wave, B = gravity and
                     acoustic waves, M = multiple effects)
        92           ground, soil, water table and atmospheric phenomena
                        (L = liquifaction, G = geyser, S = landslide/avalanche,
                         B = sand blows, C = ground cracks not known to be
                     an expression of faulting, V = visual/lights,
                         O = olfactory, M = multiple effects)
93-99            HYPOCENTER CONTRIBUTOR
        93           "<"
        94-98        contributor (left justified, "-P" means preliminary)
        99           ">"
