Abstract
Body waves critically refracted at the free surface may be the cause of the poor record quality in dry sandy loams, such as those of the extensive areas covered by the Barreiras formation in northeastern Brazil (Gomes and Souza, 1986). Records in these areas are corrupted by strong noise cones with a velocity of 340 m/s, usually identified as air‐coupled Rayleigh waves. The velocity at the top of the weathered layer should probably be at least 1.78 times the speed of sound in air for effective coupling between air waves and Rayleigh waves to take place. However, these so‐called “no‐record areas” are characterized by P-wave velocities less than the speed of sound in air.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
