The terrestrial shallow seismic reflection technique applied to the characterization and assessment of shallow sedimentary environments

Brabham, Peter; Thomas, Jessica; McDonald, Robert J.

doi:10.1144/1470-9236/04-033

Cited by 7 publications

(7 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The velocity of the upper seismic layer (1395 m s −1 ), which corresponds with resistivity zone LP‐C, is consistent with the measurement of P‐wave velocities from glaciolacustrine sediments of a similar nature found elsewhere in Wales (e.g. Camlad valley 1430 − 1500 m s −1 , Brabham et al ., 2005). Such P‐wave velocities are too low to represent competent bedrock.…”

Section: Discussionmentioning

confidence: 99%

Internal Structure and Geological Context of Ramparted Depressions, Llanpumsaint, Wales

Ross

Harris

Brabham

et al. 2011

Permafrost & Periglacial

Self Cite

View full text Add to dashboard Cite

In Europe, ramparted depressions have traditionally been interpreted as the relict forms of periglacial ground‐ice mounds. In many cases, however, such interpretations have been based on limited subsurface evidence. We present detailed sedimentological and geophysical investigations of ramparted depressions from Llanpumsaint, Wales. These data are used to establish internal structure and to evaluate possible mechanisms for landform formation. Borehole and geophysical data have revealed a thick (∼30 m) sequence of glaciolacustrine sediments beneath the study site. The geological context (drainage of a large proglacial lake) would have been conducive to the formation of: (i) permafrost‐related ground‐ice mounds, at times when exposed frost‐susceptible glaciolacustrine sediments were subject to permafrost aggradation; and (ii) craters associated with the in‐situ meltout of blocks of glacier ice grounded in the lake during periods of falling water levels. Rampart deformation structures are consistent with both models, but units of sand and gravel within the ramparts favour a hypothesis that these landforms represent the collapsed remains of ground‐ice mounds. This study highlights the importance of recognising and evaluating all possible (periglacial and non‐periglacial) models for the development of ramparted depressions. We recommend that future studies carefully consider all possible mechanisms of formation, particularly where subsurface information is limited. Copyright © 2011 John Wiley & Sons, Ltd.

show abstract

Section: Discussionmentioning

confidence: 99%

Internal Structure and Geological Context of Ramparted Depressions, Llanpumsaint, Wales

Ross

Harris

Brabham

et al. 2011

Permafrost & Periglacial

Self Cite

View full text Add to dashboard Cite

show abstract

“…Overviews of the application of seismic reflection methods to the shallow subsurface are given by Rabbel (), Steeples (, ), Steeples and Miller (, ), Brouwer and Helbig () and Brabham et al . ().…”

Section: Introductionmentioning

confidence: 97%

Hydrogeological prospecting using P‐ and S‐wave landstreamer seismic reflection methods

Pugin

Pullan

Hunter

et al. 2009

Near Surface Geophysics

View full text Add to dashboard Cite

We present two case histories from different areas and geological settings in Canada where we have used a vibrating seismic source coupled to a landstreamer receiver array in hydrogeological investigations related to aquifers in glacial sediments. In Manitoba, our P‐wave seismic reflection profiles are used to provide an assessment of the subsurface architecture of buried valleys, estimate the thickness and properties of both the channel fill and the overlying sediments to depths of ~100 m and locate optimum sites for groundwater well placements. In eastern Ontario, we collected P‐ and S‐wave seismic reflection as well as electrical resistivity data to investigate buried esker aquifers. The geophysical data provide detailed high‐resolution information (to ~30 m depth) on the structure of the esker core and its overlying sand cover and on the thickness and variability of the overlying fine‐grained aquitard. The data presented in this paper demonstrate that shallow seismic reflection methods are very effective tools to explore, assess and evaluate groundwater reservoirs and resources. The recent advent of landstreamer receiver arrays, especially when coupled to a vibratory seismic source, makes these methods significantly more cost‐effective and efficient. We now routinely collect ~1000 records/day, or 1.5‐6 line‐km/day, using our Minivib/landstreamer data acquisition system. With this type of efficient data collection, it is anticipated that the use of shallow seismic reflection methods in hydrogeological prospecting will increase as groundwater and its protection become more valued by society.

show abstract

“…The thick dry sand layer above the water table was expected to attenuate the signal. Shallow seismic techniques are generally considered unsuitable when dry unconsolidated sediments are present in the surface (Brabham, Thomas, and McDonald ). Relatively strong reflections, presumably from the water table, were seen in the test shots at offsets less than 50 m. A reflection from the bedrock was clearly seen only at offsets greater than 90 m. Reflections from the water table and the bedrock interfered with each other at distances of approximately 60 m–80 m (Fig.…”

Section: Discussionmentioning

confidence: 99%

Seismic reflection surveys in glaciofluvial deposits in Finland

Okkonen

Moisio

2015

Near Surface Geophysics

View full text Add to dashboard Cite

Shallow seismic reflection surveys were conducted at five different locations in central Finland during the period of 2008–2011 in order to test the applicability of this method and different seismic energy sources in providing accurate images of the underlying seismic structure and geology in unconfined and confined esker aquifers. The depth of the aquifers varied from 15 m to 140 m. Reflections from the water table and the bedrock were generally detected. In the deepest aquifers, several features of the inner structure were visible. In the shallowest aquifer (15 m thick), seismic detection of the stratigraphic units proved difficult. Analysis of the theoretical travel times and the shallow structure suggested that a higher frequency seismic source might have been needed. In the deeper aquifers, reflections near the bedrock were detected, but information regarding their thicknesses could not be obtained. An unsaturated layer with a thickness of 25 m did not completely attenuate the seismic signal, and reflections from the water table and bedrock (~80 m) could still be obtained. For the amount of explosives and the type of vibrator used in this study, explosives generally produced clearer reflections due to the higher signal‐to‐noise ratio compared with the vibrator source. On the other hand, shot‐to‐shot fluctuations in signal‐to‐noise ratio and source irreproducibility were found to be greater for explosives than for the vibrators. Loose lake sediments above the aquifer inhibited seismic energy transmission to the bedrock. In such situations, the use of explosives is recommended in order to obtain clearer reflections from the subsurface soil boundaries.

show abstract

The terrestrial shallow seismic reflection technique applied to the characterization and assessment of shallow sedimentary environments

Cited by 7 publications

References 39 publications

Internal Structure and Geological Context of Ramparted Depressions, Llanpumsaint, Wales

Internal Structure and Geological Context of Ramparted Depressions, Llanpumsaint, Wales

Hydrogeological prospecting using P‐ and S‐wave landstreamer seismic reflection methods

Seismic reflection surveys in glaciofluvial deposits in Finland

Contact Info

Product

Resources

About