C 1 U. S.  GEOLOGICAL SURVEY                     COASTAL AND MARINE GEOLOGY TEAM
C 2 SURVEY_ID:  J2-94-SF                         YEAR: 1994                     
C 3 AREA:   SAN FRANCISCO BAY AREA, NORTHERN CALIFORNIA                         
C 4 VESSEL:  R/V DAVID JOHNSTON                                                 
C 5 INSTRUMENT: SURFACE-TOWED SLED WITH BOOMER-PLATE SOURCE                     
C 6             AND CONE-MOUNTED IN-LINE HYDROPHONE ARRAY                       
C 7                                                                             
C 8 RECORDING PARAMETERS:                        CHANNELS PER SHOT:  1          
C 9        SAMPLE INTERVAL: 62.5 MICROSEC        SAMPLE FREQUENCY:  16 KHZ      
C10        SAMPLES/TRACE: 1600                   RECORD LENGTH:  100 MSEC       
C12 IMPORTANT NOTE: SAMPLE RATE IN SEG-Y BINARY HEADER (BYTES 3217-3218)        
C13        HAS BEEN TRUNCATED TO 62 MICROSEC, RESULTING IN AN APPARENT          
C14        RECORD LENGTH OF 99.2 MSEC                                           
C11                                                                             
C15 RECORDING FORMAT:                                                           
C16        SEG-Y 16-BIT INTEGER                                                 
C17 IMPORTANT HEADER VALUES RECORDED ON TAPE:                                   
C18    NAME    BYTES       TYPE       DESCRIPTION                               
C19   FFID       9-12    INTEGER      FIELD FILE, SHOT OR PING NUMBER           
C20   CHANNEL   13-16    INTEGER      CHANNEL NUMBER WITHIN FIELD RECORD        
C21   CDP       21-24    INTEGER      FIELD FILE, SHOT OR PING NUMBER           
C22   TYPE      29-30    INTEGER      TRACE IDENTIFICATION CODE                 
C23   NSAMPLES 115-116   INTEGER      NUMBER OF SAMPLES IN THIS TRACE           
C24   SRATE    117-118   INTEGER      SAMPLE INTERVAL IN MICROSEC FOR THIS TRACE
C25   YEAR     157-158   INTEGER      YEAR DATA RECORDED                        
C26   DAY      159-160   INTEGER      DAY OF YEAR                               
C27   HOUR     161-162   INTEGER      HOUR (24-HOUR CLOCK)                      
C28   MINUTE   163-164   INTEGER      MINUTE                                    
C29   SECOND   165-166   INTEGER      SECOND                                    
C30   TBASIS   167-168   INTEGER      TIME BASIS, ALWAYS=2 (GMT)                
C31                                                                             
C32   NOTE: LOW INPUT POWER LEVELS FROM THE ANALOG SIGNAL                       
C33   CONDITIONER RESULTED IN LOW DYNAMIC RANGE (<30 DB)                        
C34                                                                             
C35                                                                             
C36   FOR FURTHER INFORMATION CONCERNING THIS DATASET, CONTACT:                 
C37     PATRICK HART                                                            
C38     U. S. GEOLOGICAL SURVEY, M/S 999                                        
C39     345 MIDDLEFIELD RD., MENLO PARK, CALIFORNIA  94025                      
C40     (650) 329-5160     INTERNET:  HART@USGS.GOV