#define SEGY_HEAD_SIZE	240	/* segy header size in bytes */
struct segy		/* standard SEG-Y trace */
	{
	int trseql;	/*   0: trace sequence no. in line */
	int trseqr;	/*   4: trace sequence no. in reel */
	int frecno;	/*   8: original field record no. */
	int trnof;	/*  12: trace no. within original field rec */
	int sp;		/*  16: energy source point number */
	int cdpensno;	/*  20: CDP ensemble no. */
	int enstrno;	/*  24: trace number within CDP ensemble */
	short trid;	/*  28: trace id code */
	short vsumno;	/*  30: no. of vertically summed traces in trace */
	short hsumno;	/*  32: no. of horizontally summed traces in trace */
	short use;	/*  34: data use */
	int offset;	/*  36: distance from source point to receiver */
	int gz;		/*  40: elevation of receiver group */
	int szsurf;	/*  44: surface elevation at source */
	int sdepth;	/*  48: source depth below surface */
	int gdatz;	/*  52: datum elevation at receiver group */
	int sdatz;	/*  56: datum elevation at source */
	int swatdep;	/*  50: water depth at source */
	int gwatdep;	/*  54: water depth at receiver group */
	short lscaler;	/*  58: elevation and depth scaler */
	short coscaler;	/*  60: coordinate scaler */
	int sx;		/*  62: x source coordinate */
	int sy;		/*  66: y source coordinate */
	int gx;		/*  70: x receiver group coordinate */
	int gy;		/*  74: y receiver group coordinate */
	short counit;	/*  78: coordinate units */
	short vweath;	/* weathering velocity */
	short vsbweath;	/* subweathering velocity */
	short tus;	/* uphole time at source */
	short tug;	/* uphole time at receiver group */
	short dts;	/* source static correction */
	short dtg;	/* receiver group static correction */
	short dttotal;	/* total static applied */
	short tlA;	/* lag time A */
	short tlB;	/* lag time B */
	short delay;	/* recording delay time */
	short tmute0;	/* mute time start */
	short tmutef;	/* mute time end */
	short nt;	/* no. of samples in trace */
	short dt;	/* sample interval in trace */
	short gaintype;	/* gain type of field instruments */
	short kgain;	/* instrument gain constant */
	short gain0;	/* instrument early or initial gain */
	short correl;	/* correlation switch */
	short swf0;	/* sweep frequency at start */
	short swff;	/* sweep frequency at end */
	short swt;	/* sweep length */
	short swtype;	/* sweep type */
	short swtrtpt0;	/* sweep trace taper length at start */
	short swtrtptf;	/* sweep trace taper length at end */
	short swtaptype;/* sweep taper type */
	short alff;	/* alias filter frequency */
	short alfsl;	/* alias filter slope */
	short nchff;	/* notch filter frequency */
	short nchfsl;	/* notch filter slope */
	short lcf;	/* low cut frequency */
	short hcf;	/* high cut frequency */
	short lcsl;	/* low cut slope */
	short hcsl;	/* high cut slope */
	short year;	/* year data recorded */
	short jday;	/* day of year */
	short hour;	/* hour of day */
	short minute;	/* minute of hour */
	short second;	/* second of minute */
	short tbasis;	/* time basis code */
	short trwt;	/* trace weighting factor */
	short rsw1gno;	/* geophone group no. of roll switch pos. 1 */
	short frtr1gno;	/* grp. no. of trace 1 w/i orig. field rec. */
	short frtrfgno;	/* grp. no. of last trace w/i field rec. */
	short gapsize;	/* gap size */
	short overtrav;	/* overtravel assoc. w/ taper at line ends */
	float fdt;	/* floating residual static correction */
	float fdts;	/* floating residual shot static */
	float fdtg;	/* floating residual receiver static */
	float fdtd;	/* floating residual depthpoint static */
	float fdtmo;	/* floating residual moveout static */
	char unas[40];	/* unassigned */
	};