ISO 3482:2022

INTERNATIONAL ISO
STANDARD 3482
First edition
2022-05
Ships and marine technology —
Technical guidelines for active source
exploration with ocean bottom
seismometers (OBS)
Navires et technologie maritime — Lignes directrices techniques
relatives à l'exploration des sources actives avec des sismomètres de
fond de mer (OBS)
Reference number
© ISO 2022
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ii
Contents Page
Foreword .iv
Introduction .v
1 S c op e . 1
2 Nor m at i ve r ef er enc e s . 1
3 Terms and definitions . 1
4 R e qu i r ement s . 3
4.1 General . 3
4.2 S tandard of time and space . 3
4.2.1 S tandard of time . 3
4.2.2 C oordinate system . 3
4.2.3 Vertical reference . 3
4.2.4 P ositioning system . 3
4.3 O BS technical indicators . 3
4.3.1 OBS acquisition system . 3
4.3.2 O BS deployment/recovery system . 3
4.3.3 Power supply system . 4
4 .4 S ei s m ic s ou r c e s . 4
4 . 5 F ield de s i g n . 4
4.6 Marine exploration process . 5
4.6.1 OBS preparation . 5
4.6.2 R elevant software, media and files . 5
4.6.3 OBS parameter setting . 5
4.6.4 G lass ball sealing . 6
4.6.5 P ressure tubes . . 6
4.6.6 O BS deployment and recovery . 6
4.6.7 Voyage requirements. 7
4.6.8 T iming and positioning . 7
4.6.9 O peration log . 7
4.7 F ield data . 8
4.7.1 R aw data . 8
4.7.2 R elevant data . 8
4.8 D ata processing and archiving . 8
4.8.1 Data processing . 8
4.8.2 D ata archiving and reports . 9
Bibliography .10
iii
Foreword
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This document was prepared by Technical Committee ISO/TC 8, Ships and marine technology,
Subcommittee SC 13, Marine technology.
Any feedback or questions on this document should be directed to the user’s national standards body. A
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iv
Introduction
Exploration for the structures and movement of deep earth on the seafloor is one of the important
approaches for human beings to recognize earth system evolution, predict seabed resources formation,
and understand natural disaster mechanisms. Unlike the multi-channel seismic method which only
obtains primary waves by hydrophone streamers on the ocean surface, the ocean bottom seismometer
(OBS) is directly placed on the seabed and can receive both primary and shear waves, even Rayleigh
and Love waves from earth interior. Such a new seismic method gives an opportunity to better image
the structures, movement and rheology for the deep targets in solid earth beneath ocean which cover
up to ≈71 % of the earth’s surface. This method has been widely used in research on not only global
continental margins, subduction zones, mid-ocean ridges, but also regional oil and gas fields, marine
engineering constructions.
The signals received in OBS exploration can be either natural earthquakes or artificial excited seismic
sources. Accordingly, OBS exploration is divided into passive and active source methods. Passive source
exploration with OBS is a method by which OBSs just receive global natural earthquakes and obtain
deeper and wider information from the earth interior. Active source exploration with OBS is usually
used in a target region to reveal the structures, tectonics and composition of underground geological
bodies or crust and upper mantle by a special designed array of OBSs and sources. Because of its
strong pertinence, this active source method gradually becomes the main tool for regional deep earth
exploration, and is widely used by industry and academia.
OBS is a mature technical product and widely used in various deep earth imaging. However, there is a
lack of such a standard about active source exploration with OBS, which will seriously affect the testing,
identifying, evaluating of the performance requirements and data quality of such products. It should
therefore be necessary to standardize its technical requirements and basic procedures to promote
healthy development of this industry of seabed OBS exploration. In view of the above, this document
establishes the technical guidelines covering the main content of active source exploration with OBS
from OBS instruments, seismic sources and fieldwork processes, to data services.
v
INTERNATIONAL STANDARD ISO 3482:2022(E)
Ships and marine technology — Technical guidelines for
active source exploration with ocean bottom seismometers
(OBS)
1 S cope
This document specifies the technical requirements for system makeup, ocean bottom seismometer
(OBS) instruments, active sources, field design, exploration operation, data processing for active source
exploration with OBS, and their relative terms.
This document is applicable to active source exploration with OBS, but also a useful reference to the
passive source exploration with OBS. It can be used in seabed resource exploration, geological disaster
surveillance and submarine geoscience research.
2 Normat ive references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
ocean bottom seismometer
OBS
seismic observation system with a seismic sensor placed on the seabed to record ground motions and
an acoustic sensor to record signals in the water column
Note 1 to entry: The main components include seismic sensing system (3.3) and acoustic sensing system (3.4),
recording and storage unit (3.5), release unit (3.8), acoustic communication unit (3.7), compass, internal clock,
power supply, lighting system, cargo compartment and protective cover etc.
Note 2 to entry: There are mainly two types of OBS, broadband and short period. The short period OBS, with the
lower corner of its frequency band not less than 2 Hz, usually used for active seismic source exploration.
3.2
active source exploration
exploration method in which sound wave signals are emitted in the water by ship-borne seismic sources
such as air gun, propagated downward through the crust and u
...