QSELECT(1Q) MISC. REFERENCE MANUAL PAGES QSELECT(1Q) NAME qselect - filter to select earthquakes satisfying user- defined criteria SYNTAX qselect [_o_p_t_i_o_n...] [_f_i_l_e...] DESCRIPTION qselect reads earthquake catalog cards (``summary cards'') from an on-line catalog or the specified _f_i_l_e_s (standard input default), and outputs those whose locations, magni- tudes, or other characteristics agree with criteria speci- fied in the command-line _o_p_t_i_o_ns. OPTIONS The following command-line _o_p_t_i_o_ns can be used to control the program. Options are scanned from left to right; if conflicting _o_p_t_i_o_ns are given, the rightmost one takes pre- cedence. Only enough characters need be given to uniquely identify an _o_p_t_i_o_n. -help [_o_p_t_i_o_n ...] Print brief explanations of the meanings of the named _o_p_t_i_o_ns. If no _o_p_t_i_o_ns are named, descriptions are printed for all _o_p_t_i_o_n_s. The explanations are written to the standard error output. -latitude _m_i_n _m_a_x Selects earthquakes with latitudes between _m_i_n and _m_a_x. These limits are measured in degrees, and may option- ally be followed by one or two fields specifying minutes and seconds. If multiple fields are used, they must be separated from each other by colons : . For example, 37.5 and 37:30 both specify the same latitude -- the first specifies it in decimal degrees, and the second specifies it in degrees and minutes. -longitude _m_i_n _m_a_x Selects earthquakes with longitudes between _m_i_n and _m_a_x. These are in the same format as the latitude lim- its, described above. (Note: West longitudes are negative!) -depth _m_i_n _m_a_x Selects earthquakes with focal depths between _m_i_n and _m_a_x (km). -time _s_t_a_r_t _e_n_d Selects earthquakes with origin times between the epochs _s_t_a_r_t and _e_n_d, which are given in the form [cc]yymmddhhmmss . If the century is not given, the twentieth century is assumed. The seconds field may Sun Release 4.1 Last change: 19 March 1986 1 QSELECT(1Q) MISC. REFERENCE MANUAL PAGES QSELECT(1Q) contain a decimal point and a fractional part, but in any case the integral part must be two digits, even if they are zeros. An epoch may optionally be followed by an offset consisting of a + or - sign and one or more occurrences of a number followed by a d, h, m, or s character (for days, hours, minutes, or seconds). For example, +1.5d and +1d12h mean the same thing. This option is also used with the -catalog entry to limit the number of catalog files to search. -magnitude _m_i_n _m_a_x Selects earthquakes with magnitudes between _m_i_n and _m_a_x. -closest _m_i_n _m_a_x Selects earthquakes with distances to the closest sta- tion between _m_i_n and _m_a_x (km). -nstations _m_i_n _m_a_x Selects earthquakes with the number of stations between _m_i_n and _m_a_x. -rms _m_i_n _m_a_x Selects earthquakes with root-mean-squared residuals between _m_i_n and _m_a_x (s). -gap _m_i_n _m_a_x Selects earthquakes with azimuthal gaps between _m_i_n and _m_a_x (deg). -quality _l_e_t_t_e_r_s Selects earthquakes with specified quality codes (e.g. acd). The difference between upper and lower case letters is ignored. -polygon _l_a_t _l_o_n... Selects earthquakes within a polygon. The polygon is specified as three or more pairs of values, each pair giving the latitude and longitude of a vertex of the polygon. The format of these latitudes and longitudes is the same as that for latitude limits, described above. (Note: West longitudes are negative!) -delta _l_a_t _l_o_n _m_i_n _m_a_x Selects earthquakes whose distance from the point (_l_a_t, _l_o_n) is between _m_i_n and _m_a_x. The format for _l_a_t and _l_o_n is the same as that for latitude limits, described above. (Note: West longitudes are negative!) _M_i_n and _m_a_x are measured in kilometers. -catalog Specifies that the on-line catalog should be searched Sun Release 4.1 Last change: 19 March 1986 2 QSELECT(1Q) MISC. REFERENCE MANUAL PAGES QSELECT(1Q) in addition to any specified input files. The variable CUSPCATDIR, which can be specified in either the system-wide LOCATIONS file or as an environment vari- able, specifies the directory that contains the monthly catalog files. Note that input will NOT be read from stdin when this option is used. EXAMPLES To select earthquakes larger than magnitude 3 from the entire on-line catalog: qselect -catalog -mag 3 10 To select earthquakes within a two-day interval from the catalog set t=840301123456.7 qselect -catalog -time $t-2d $t To select earthquakes from the catalog using a number of options, which are stored in the file option_file (Note the use of grave accents, not to be confused with apostrophes): qselect -catalog `cat option_file` To re-select events that were previously extracted into mul- tiple files ending in .subset use one of the following: cat *.subset | qselect ... qselect ... *.subset NOTES It is STRONLY suggested that you limit your searches when- ever possible with the -time option whenever you use the -catalog option. Otherwise, all catalog files on the system will be searched, and this can take a considerable amount of time. AUTHOR Bruce R. Julian, USGS Menlo Park, Calif. Modified by Doug Neuhauser, UCB Seismographic Station, Calif. Sun Release 4.1 Last change: 19 March 1986 3