Swell filter

The term swell filter in high resolution seismics (reflection seismology) or sub bottom profiling refers to the static correction that restores the coherence of a high resolution seismic profile. The coherence of the image got lost because of the relative movement (a function of the wavelength of the signal and the swell) of the source and receiver during the recording. In normal seismic recordings, the term swell filter refers to filtering the acoustic noise, created by waves, out of the seismic recording.

High resolution seismics and subbottom profiling

Very high resolution seismics (reflection seismology) is applied to make detailed acoustic profiles of a sea floor or lake floor. Acoustic sources used include: air gun, water gun, sleeve gun, sparker and boomer. The frequency used in this field ranges from 100 Hz to 10.000 Hz.

Subbottom profiling is a technique used in acoustical oceanography. Sonars or echo sounder are typical sources for very high resolution imaging. Also used in this field are parametric echosounders. The main difference with the high resolution seismics is the type of source used.

Problematic swell

When the movement of the platform and equipment due to swell is too heavy during a seismic recording, the coherence of the image gets lost. The reason why it gets lost is because the movement of source and receiver is larger than the wavelength of the signal produced by the source. As such the seismic reflectors do not line up.

A detail of a seismic profile recorded during heavy weather.The same profile swell filtered.

More examples can be found in the example section of www.swellfilter.com [http://www.swellfilter.com]

How to build your own swell filter

Building a swell filter is relatively simple: find a good first break detection algorithm (detection of the sea floor) and bandpass the array. Now calculate the static shifts between the original and band passed array and apply them.

ee also

*SEG Y - a popular file format for seismic reflection data
*Depth conversion - the conversion of acoustic waves two-way travel time to actual depth
*Seismic waves
*Seismic refraction

External links

* [http://sepwww.stanford.edu/research Reflection Seismology Literature at Stanford Exploration Project]
* [http://www.iagc.org Website of the International Association of Geophysical Contractors]
* [http://www.iagc.info/webdata/public/news/IAGC-OGP_Joint%20Position%20Paper_Marine%20Mammals_2004_09_29.pdf IAGC/OGP position paper on seismic surveys and marine mammals] (PDF)
* [http://www.swellfilter.com Swellfilter.com for more examples and information ]

Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Reflection seismology — (or seismic reflection) is a method of exploration geophysics that uses the principles of seismology to estimate the properties of the Earth s subsurface from reflected seismic waves. The method requires a controlled seismic source of energy,… …   Wikipedia

  • Interstate 70 — Infobox road type=I route=70 length mi=2153.13 length round=2 length ref=cite web |url=http://www.fhwa.dot.gov/reports/routefinder/table1.htm|title=Route Log Main Routes of the Eisenhower National System of Interstate and Defense Highways Table… …   Wikipedia

  • DOD Electronics — For other uses, see DOD (disambiguation). DOD Electronics or simply DOD is a Harman International company specializing in making guitar effects pedals, most of which are now discontinued. Additionally, the company has made active crossover gear.… …   Wikipedia

  • Drug injection — Shoot up redirects here. For shooting video game genre, see Shoot em up. This article is not about medical practice. For medical practices, see Intramuscular injection or Intravenous therapy. A piece of a hypodermic needle, as seen on X ray, in… …   Wikipedia

  • Cannabis cultivation — Typical home grown organic sinsemilla bud compared to a cigarette pack. This article presents common techniques and facts regarding the cultivation of the flowering plant cannabis, primarily for the production and consumption of marijuana buds.… …   Wikipedia

  • Environmental threats to the Great Barrier Reef — The Great Barrier Reef is the world s largest coral reef system,cite web|author=UNEP World Conservation Monitoring Centre |year=1980|title=Protected Areas and World Heritage Great Barrier Reef World Heritage Area|url=http://sea.unep… …   Wikipedia

  • Disney Pixar Cars Die-Cast Line — In April 2006, Mattel began releasing 1:55 scale die cast models of characters from the Disney Pixar film, Cars . Mattel has released these toys in a number of waves. =Series 1=While not the official name for the series, the initial wave in the… …   Wikipedia

  • protozoan — /proh teuh zoh euhn/, n., pl. protozoans, (esp. collectively) protozoa / zoh euh/, adj. Biol. n. 1. any of a diverse group of eukaryotes, of the kingdom Protista, that are primarily unicellular, existing singly or aggregating into colonies, are… …   Universalium

  • Nemertea — For the Romanian village that bears this name, see Gura Teghii. Nemertea …   Wikipedia

  • Exposure (photography) — Underexposure redirects here. For the 2005 film by Oday Rasheed, see Underexposure (2005 film). A long exposure showing stars rotating around the southern and northern celestial poles. Credit: European Southern Observatory …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.