C1  U.S GEOLOGICAL SURVEY, WESTERN COASTAL AND MARINE GEOLOGY                   
   C2  CRUISE ID: J497SF          SAN FRANCISCO BAY AREA                           
   C3  YEAR COLLECTED: 1997       VESSEL: R/V DAVID JOHNSTON                       
   C4  SAMPLE INTERVAL: 2 MSEC    SAMPLES PER TRACE: 1000                          
   C5  RECIEVER: 240 METER LENGTH STREAMER, 24 CHANNEL                             
   C6            THREE HYDROPHONES PER CHANNEL                                     
   C7  GROUP INTERVAL: 10 METERS   SHOT INT: 10, 15 OR 20 METERS                   
   C8  SOURCE: ONE 35 CUBIC INCH G. I. AIR GUN                                     
   C9  CDP INTERVAL: 5 METERS      RECORD LENGTH: 2.0 SECONDS                      
   C10                                                                             
   C11 IMPORTANT HEADER WORDS AND THEIR LOCATIONS:                                 
   C12 NAME   BYTE LOCATION  LENGTH  FORMAT                                        
   C13 FFID/SHOT        9-12     4      INTEGER                                    
   C14 CDP NUMBER      21-24     4      INTEGER                                    
   C15 CDP-X (UTM)   181-184     4      INTEGER                                    
   C16 CDP-Y (UTM)   185-188     4      INTEGER                                    
   C17 UTM COORDINATES ARE EASTINGS AND NORTHING IN METERS IN UTM ZONE 10          
   C18 LATITUDE      189-192     4      FLOATING POINT                             
   C19 LONGITUDE     193-196     4      FLOATING POINT                             
   C20 LATITUDE/LONGITUDE VALUES ARE IN DECIMAL DEGREES                            
   C21                                                                             
   C22 THIS FILE CONTAINS 6 TO 12-FOLD STACKED MARINE SEISMIC REFLECTION DATA      
   C23 PRESTACK PROCESSING INCLUDED CDP SORTING, VELOCITY ANALYSIS,                
   C24 DECONVOLUTION, BAND-PASS FILTERING (50-200 HZ), AUTOMATIC                   
   C25 GAIN CONTROL, NORMAL MOVE-OUT CORRECTION AND STACKING.                      
   C26 NO POST-STACK PROCESSING HAS BEEN APPLIED.                                  
   C27 DATA FORMAT IS 32-BIT FLOATING POINT SEG-Y.                                 
   C28                                                                             
   C29                                                                             
   C30 FOR FURTHER INFORMATION CONTACT:                                            
   C31 RAY SLITER OR PATRICK HART                                                  
   C32 U.S. GEOLOGICAL SURVEY                                                      
   C33 345 MIDDLEFIELD ROAD, MAIL STOP 999                                         
   C34 MENLO PARK, CA 94025                                                        
   C35 (650) 853-8300                                                              
   C36 E-MAIL: RSLITER@USGS.GOV OR HART@USGS.GOV                                   
   C37                                                                             
   C38                                                                             
   C39                                                                             
   C40