Editing Reflection seismology (section)

====Ground roll / Rayleigh wave / Scholte wave / Surface wave====
A [[Rayleigh wave]] typically propagates along a free surface of a solid, but the elastic constants and [[density]] of air are very low compared to those of rocks so the surface of the Earth is approximately a [[free surface]]. Low velocity, low frequency and high amplitude Rayleigh waves are frequently present on a seismic record and can obscure signal, degrading overall data quality.  They are known within the industry as ‘Ground Roll’ and are an example of coherent noise that can be attenuated with a carefully designed seismic survey.<ref>{{cite web | website = [[Schlumberger]] Oilfield Glossary | title = Ground Roll | url = http://www.glossary.oilfield.slb.com/Display.cfm?Term=ground%20roll | access-date = 8 September 2013 | archive-date = 31 May 2012 | archive-url = https://web.archive.org/web/20120531161347/http://www.glossary.oilfield.slb.com/Display.cfm?Term=ground%20roll | url-status = dead }}</ref>  The [[Scholte wave]] is similar to
ground roll but occurs at the sea-floor (fluid/solid interface) and it can possibly obscure and mask deep reflections in marine seismic records.<ref>{{cite arXiv|eprint=1306.4383|last1=Zheng|first1=Yingcai|title=Scholte waves generated by seafloor topography|last2=Fang|first2=Xinding|last3=Liu|first3=Jing|last4=Fehler|first4=Michael C.|year=2013|class=physics.geo-ph}}</ref> 
The velocity of these waves varies with wavelength, so they are said to be dispersive and the shape of the wavetrain varies with distance.<ref>Dobrin, M. B., 1951, Dispersion in seismic surface waves, Geophysics, 16, 63–80.</ref>