alexa Abstract | Comparison of the Characteristics of Low Velocity Layer (LVL) in the Mangrove Swamp and in the Upper Flood Plain Environments in the Niger Delta, using Seismic Refraction Methods
ISSN: 2381-8719

Journal of Geology & Geophysics
Open Access

OMICS International organises 3000+ Global Conferenceseries Events every year across USA, Europe & Asia with support from 1000 more scientific Societies and Publishes 700+ Open Access Journals which contains over 50000 eminent personalities, reputed scientists as editorial board members.

Open Access Journals gaining more Readers and Citations

700 Journals and 15,000,000 Readers Each Journal is getting 25,000+ Readers

This Readership is 10 times more when compared to other Subscription Journals (Source: Google Analytics)

Research Article Open Access


Sixteen (16) surface-laid-geophones and fourteen (14) downhole-laid-hydrophones experiments were conducted in Upper Flood Plain and in Mangrove Swamp areas respectively in parts of the Niger Delta. The aim is to compare low-velocity-layer (LVL) characteristics in the two environments. The velocity and depth of the weathered layer and those of the consolidated layers were calculated using depth-time plots. The interpreted data showed a substantial variation of the weathered layer thickness and elevation in the two study areas. In the Upper Flood Plain, LVL thickness varies between 2.8 m and 40 m with an average of 21.46 m. In the Mangrove Swamp, the thickness varies between 2.0 m and 5.5 m with an average of 3.40 m. The weathered layer thickness in the Mangrove Swamp is fairly uniform having an average of 3.4 m. This highly variable LVL thickness indicates the necessity of correcting for this layer during seismic reflection processing. A close study of the results reveals a thickening of the weathered layer northwards accompanying the increase in elevation. Elevations in Upper Flood Plain vary between 3.4 m and 156 m with average of 69.90 m; the elevations in Mangrove Swamp vary between-0.10 m (sub-sea) and 0.4 m with an average -0.0043 m implying that the topography of the Mangrove Swampy area is highly variable and undulated. The weathered layer velocity in the Upper flood Plain varies between 313.67 ms-1 and 984 ms-1 with average of 438.80 ms-1. In the Mangrove Swamp, weathered layer velocity varies between 294.5 ms-1 and 863 ms-1 with average of 524.10 ms-1. The average velocities of the underlying consolidate layer in the Upper Flood and Mangrove Swamp are 1753.28 ms-1 and 1603.51 ms-1 respectively depicting a general increase in the velocity with amount of consolidation of the bedrock in the two areas. Analysis of the velocity spectra suggests that low air-blast velocity, of the order of laboratory velocity of sound in air of 343 ms-1 at 20°C resulting from direct blast waves could have been drawn in. For the dry Upper Flood Plain and moist-laden Mangrove Swamp, the air-blast velocities are 346.80 ms-1 and 539.70 ms-1 respectively at 27°C which is the average atmospheric temperature in the Niger Delta. The results of this work compare closely with those of Uko et al., Eze and Okwueze, Enikanselu, Lazzari et al., Ibogboekwe and Ohaegbuchu, and Ofomola who worked on LVL characteristic in different environments in the Niger Delta. The results of this work can used for static correction in seismic processing, for planning and assessing risk for engineering structures, and for groundwater exploration.

To read the full article Peer-reviewed Article PDF image | Peer-reviewed Full Article image

Author(s): Uko ET, Emudianughe JE and Eze CL


Geophones, Hydrophones, Near-surface, Mangrove swamp, Flood plain, Seismic refraction, Time-offset depth-velocity conversions, Chemical Geology, Deposition Geology, Exploration Geophysics, Forensic Geology

Share This Page

Additional Info

Loading Please wait..
Peer Reviewed Journals
Make the best use of Scientific Research and information from our 700 + peer reviewed, Open Access Journals
International Conferences 2017-18
Meet Inspiring Speakers and Experts at our 3000+ Global Annual Meetings

Contact Us

© 2008-2017 OMICS International - Open Access Publisher. Best viewed in Mozilla Firefox | Google Chrome | Above IE 7.0 version