Dublin City 2D seismic reflection survey

Description du marché

• Design and simulation of subsurface coverage of a seismic survey in order to image strata at depths of at least 2 km around the target area. The lithology is expected to consist of argillaceous and clean limestones, with basement potentially occurring at approximately 2 km. • The survey design will need to reflect the operational constraints of seismic acquisition within a built-up urban environment. The GSI and its representatives can support design by providing geological information. The proposed design will be approved by GSI and the project Steering Group. • Engagement with the relevant authorities in Dublin City Council and the utility companies regarding road access, traffic management, sensitive or restricted areas, etc. (Pre-engagement is currently underway and an information pack will be provided with the CfT.) • Design and execution of a communications plan for all dwellings and businesses along the proposed routes. The communications plan is to be produced in collaboration with GSI and its representatives, other relevant organisations (including Dublin City Council, Grangegorman Development Agency and Technical University Dublin) and the GEMINI project, and will be approved by GSI and the project steering group. • Nodal seismic acquisition to be deployed on two (2) roughly orthogonal lines centred on the TUD Grangegorman campus in Dublin 7. Estimated length of lines is up to 7 km each, with one line trending NNW-SSE and the other ENE-WSW. Nodal spacing should be sufficient to meet the challenges presented by the acquisition environment and is anticipated to be approximately 10 metres spacing. Nodes should be fitted with either a piezometric accelerometer or a geophone. • Mobilisation and transport of a seismic vibrator source of sufficient energy to image strata at depths of at least 2 km around the target area), providing frequencies within the range of approximately 5 – 125 Hz. Innovative solutions to acquire high quality data in an urban environment while managing PPV levels may be required. It is envisaged that a Vibration Point spacing of no more than 20 metres will be required. • Management of all operations associated with the seismic reflection survey, including liaison with Dublin City Council and utilities representatives, in-survey community liaison, vibration monitoring and real-time management of source energy to meet local PPV requirements. • Processing of all seismic reflection data acquired during the survey using methodologies particularly suited to urban noise attenuation and geological signal enhancement. • Development of an appropriate velocity model and depth conversion of the seismic reflection data.

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