Seismic investigations in downtown Copenhagen, Denmark
Martinez, K. and Mendoza, J. A. LU
(2009)
AGU (American Geophysical Union) Spring Meeting, 2009
In Eos
90(52, SUPPL.).
p.13-1148
- Abstract
- Near surface geophysics are gaining widespread use in major infrastructure projects with respect to geotechnical and engineering applications. The development of data acquisition, processing tools and interpretation methods have optimized survey production, reduced logistics costs and increase results reliability of seismic surveys during the last decades. However, the use of geophysical methods under urban environments continues to face challenges due to multiple noise sources and obstacles inherent to cities. A seismic investigation was conducted in Copenhagen aiming to produce information needed for hydrological, geotechnical and groundwater modeling assessments related to the planned Cityringen underground metro project. The particular... (More)
- Near surface geophysics are gaining widespread use in major infrastructure projects with respect to geotechnical and engineering applications. The development of data acquisition, processing tools and interpretation methods have optimized survey production, reduced logistics costs and increase results reliability of seismic surveys during the last decades. However, the use of geophysical methods under urban environments continues to face challenges due to multiple noise sources and obstacles inherent to cities. A seismic investigation was conducted in Copenhagen aiming to produce information needed for hydrological, geotechnical and groundwater modeling assessments related to the planned Cityringen underground metro project. The particular objectives were a) map variations in subsurface Quaternary and limestone properties b) to map for near surface structural features. The geological setting in the Copenhagen region is characterized by several interlaced layers of glacial till and meltwater sand deposits. These layers, which are found unevenly distributed throughout the city and present in varying thicknesses, overlie limestone of different generations. There are common occurrences of incised valley structures containing localized instances of weathered or fractured limestone. The surveys consisted of combined seismic reflection and refraction profiles accounting for approximately 13 km along sections of the projected metro line. The data acquisition was carried out using standard 192 channels arrays, receiver groups with 5 m spacing and a Vibroseis as a source at 5 m spacing. In order to improve the resolution of the data, 29 Walkaway-Vertical Seismic Profiles were performed at selected wells along the surface seismic lines. The refraction data was processed with travel-time tomography and the reflection data underwent standard interpretation. The refraction data inversion was performed twofold; a surface refraction alone and combined with the VSP data. Three general velocity layers were observed; 800-1250 m/s, 1250-1700 m/s and a high velocity layer 1700-2500 m/s with localized zones of greater velocities. The variations in the higher velocity layer provide information on limestone properties relevant for tunneling design. The Walkaway-VSP proved to be a useful tool for identifying the velocity fields corresponding to the shallow sediments and the deep sequences of limestone, thus aiding the interpretation of the surface refraction imaging. Data acquisition was planned overnight to reduce external noise impact and optimise production, and urban challenges (e.g. traffic, pipelines) were overcome. Further integrated geophysical interpretation will be done together with hydrogeological analyses, geotechnical evaluations and geological modelling. The authors acknowledge Metroselskabet I/S for permission to present these results, and the Cityringen Joint Venture partners COWI, Arup and Systra. (Less)
Please use this url to cite or link to this publication:
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- author
- Martinez, K.
and Mendoza, J. A.
LU
- publishing date
- 2009
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Engineering geology; 30, Applied geophysics; 20, Copenhagen Denmark;, Denmark;, Europe;, geophysical methods;, geophysical profiles;, geophysical surveys;, infrastructure;, reflection;, Scandinavia;, seismic methods;, seismic profiles;, surveys;, underground installations;, urban environment;, Western Europe;
- in
- Eos
- volume
- 90
- issue
- 52, SUPPL.
- pages
- 13 - 1148
- publisher
- American Geophysical Union (AGU)
- conference name
- AGU (American Geophysical Union) Spring Meeting, 2009
- conference location
- Toronto, Canada
- conference dates
- 2009-05-24 - 2009-05-27
- ISSN
- 0096-3941
- language
- English
- LU publication?
- no
- additional info
- Accession Number: 2014-008860; Conference Name: American Geophysical Union 2009 fall meeting; San Francisco, CA, United States; Conference Date: 20091214; Language: English; Coordinates: N554000N554000E0123500E0123500; Coden: EOSTAJ; Collation: Abstract NS13A-1148; Publication Types: Serial; Conference; Abstract Only; Updated Code: 201404; Monograph Title: AGU 2009 fall meeting; Monograph Author(s): Anonymous; Reviewed Item: Analytic
- id
- 4ef9ec39-ab0c-49f0-8b67-e8b9ba86ae1c
- date added to LUP
- 2022-12-01 16:56:13
- date last changed
- 2022-12-05 11:19:28
@misc{4ef9ec39-ab0c-49f0-8b67-e8b9ba86ae1c,
abstract = {{Near surface geophysics are gaining widespread use in major infrastructure projects with respect to geotechnical and engineering applications. The development of data acquisition, processing tools and interpretation methods have optimized survey production, reduced logistics costs and increase results reliability of seismic surveys during the last decades. However, the use of geophysical methods under urban environments continues to face challenges due to multiple noise sources and obstacles inherent to cities. A seismic investigation was conducted in Copenhagen aiming to produce information needed for hydrological, geotechnical and groundwater modeling assessments related to the planned Cityringen underground metro project. The particular objectives were a) map variations in subsurface Quaternary and limestone properties b) to map for near surface structural features. The geological setting in the Copenhagen region is characterized by several interlaced layers of glacial till and meltwater sand deposits. These layers, which are found unevenly distributed throughout the city and present in varying thicknesses, overlie limestone of different generations. There are common occurrences of incised valley structures containing localized instances of weathered or fractured limestone. The surveys consisted of combined seismic reflection and refraction profiles accounting for approximately 13 km along sections of the projected metro line. The data acquisition was carried out using standard 192 channels arrays, receiver groups with 5 m spacing and a Vibroseis as a source at 5 m spacing. In order to improve the resolution of the data, 29 Walkaway-Vertical Seismic Profiles were performed at selected wells along the surface seismic lines. The refraction data was processed with travel-time tomography and the reflection data underwent standard interpretation. The refraction data inversion was performed twofold; a surface refraction alone and combined with the VSP data. Three general velocity layers were observed; 800-1250 m/s, 1250-1700 m/s and a high velocity layer 1700-2500 m/s with localized zones of greater velocities. The variations in the higher velocity layer provide information on limestone properties relevant for tunneling design. The Walkaway-VSP proved to be a useful tool for identifying the velocity fields corresponding to the shallow sediments and the deep sequences of limestone, thus aiding the interpretation of the surface refraction imaging. Data acquisition was planned overnight to reduce external noise impact and optimise production, and urban challenges (e.g. traffic, pipelines) were overcome. Further integrated geophysical interpretation will be done together with hydrogeological analyses, geotechnical evaluations and geological modelling. The authors acknowledge Metroselskabet I/S for permission to present these results, and the Cityringen Joint Venture partners COWI, Arup and Systra.}},
author = {{Martinez, K. and Mendoza, J. A.}},
issn = {{0096-3941}},
keywords = {{Engineering geology; 30; Applied geophysics; 20; Copenhagen Denmark;; Denmark;; Europe;; geophysical methods;; geophysical profiles;; geophysical surveys;; infrastructure;; reflection;; Scandinavia;; seismic methods;; seismic profiles;; surveys;; underground installations;; urban environment;; Western Europe;}},
language = {{eng}},
note = {{Conference Abstract}},
number = {{52, SUPPL.}},
pages = {{13--1148}},
publisher = {{American Geophysical Union (AGU)}},
series = {{Eos}},
title = {{Seismic investigations in downtown Copenhagen, Denmark}},
volume = {{90}},
year = {{2009}},
}