Coastal and Marine Geology Metadata and Data
Dictionaries: Data Dictionary Metadata Dictionary
See also, National Archive of Marine Seismic Surveys (NAMSS).
Seismic information covers a wide range of information including:
|conventional multichannel||seismic reflection profile data typically acquired with a large multiple airgun array; 10 to 100 Hz spectral content (2 ms sample) and 8 to 20 sec record length; CDP interval typically 25 to 100 meters; 12 to 48 fold.|| 24 Channel
|high-resolution multichannel||seismic reflection profile data typically acquired with a single small airgun, GI gun or watergun; 50 to 500 Hz spectral content (0.5 ms sample) and 1 to 2 sec record length; CDP interval typically 3 to 5 meters; 6 to 24 fold.|| GI Gun
|conventional single channel||seismic reflection profile data typically acquired with a large (10 to 20 kJ large airgun or multiple airgun array; 10 to 100 Hz spectral content and 8 to 10 sec record length; shot interval typically 25 to 50 m; no fold; prior to 1990, rarely digitally recorded.|| Airgun
|high resolution single channel||seismic reflection profile data typically acquired with a small sparker (2 kJ), small airgun, GI gun, or watergun; often includes two-channel data, which are independent receivers; spectral content 100 to 1000 Hz (0.25 to 0.5 ms sample); shot interval 3 to 10 meters.|| Minisparker
|very high resolution single channel||seismic reflection profile data typically acquired with any of a wide variety of electromechanical transducers, broadly classed as wide-band (boomer, geopulse, seistec) or narrow-band (chirp); spectral content 1000 to 10000 Hz (sample rate 8 to 32 kHz); shot (or ping) frequency 0.125 to 0.5 sec (0.2 to 1 meter).|| 3.5 kHz
|wide angle reflection/refraction||seismic reflection/refraction profile data typically acquired with a large airgun source to offsets of 20 to 100 km.|| Ocean Bottom Hydrophone
Ocean Bottom Seismometer
Seismic data are collected by "shooting" a source at either:
Each "shot" is an actual sound burst in the water.
Time associated with shots and with navigation are used for plotting on a map.
Shots can have other names like:
"CDPs" (Common Depth Point), sometimes called CMP (Common Mid-Point)
But, how is the latitude and longitude of each CDP location, when the navigation is for the ship at a certain time and no unique time is associated with a CDP?
|scattered||< Activity-ID >.4## files containing time sequential information along ship tracks.|
|metadata||information about seismic analog paper rolls, inventory of gear, operation of gear, magnetic tapes, and paper printer listings|
Seismic data file names:
|<Activity-ID>.40#||Raw seismic shot points|
|<Activity-ID>.42#||Edited seismic shot points|