Post Doc Opportunity: 
Optimisation of DCIP Surveying and Monitoring in Complex Environments 

There is an opening for a post doc position at Engineering Geology, Lund University, on optimisation of DCIP surveying and monitoring in complex environments.  

Background
Electric resistivity tomography (ERT) has developed tremendously in the last 20 years and 2D ERT is nowadays a standard tool in engineering and environmental applications. In case of complex environments the 2D approach is, however, not always sufficient but 3D ERT may be required. This can be the case for investigations of old landfills where the distribution of buried waste is strongly heterogeneous. Mapping of contaminated land can also be very challenging due to complex flow patterns in preferential pathways. There is furthermore a growing need for mapping of underground structures in urban areas which calls for 3D approaches due to limitations in possible placement of electrode spreads and complex geometries in the underground.

It has been shown that combined ERT incorporating DC resistivity as well as time‐domain induced polarisation (DCIP) can yield valuable additional information compared to measuring resistivity alone.

This is well proven for mapping of buried waste, but there is large potential for enhanced characterisation of contaminated ground as well as natural geological materials. The latter is expected to benefit from on‐going work on extracting spectral IP information from data measured in time‐domain.

There are a number of limitations and problems in connection with 3D DCIP tomography. First of all it requires electrodes to be placed in a pattern that may be relatively unrestricted or strongly restricted depending on the site conditions. In any case the optimal way to place the electrodes for efficient tomography demands further research. Furthermore very large numbers of data can be recorded on such a spread of electrodes, and it is necessary to select time optimised measurement sequences for practical applications. The need for time optimisation is further emphasised by the wide range of IP time windows required for spectral IP (SIP), where long integration times can make measurements very time consuming.  Another consideration for SIP is that early decay times are very challenging from a noise point of view due to short time for data averaging (noise suppression) and sensitivity to coupling in electrode cables.

Optimisation as outlined above is important not only for site investigation by also for monitoring applications. 3D data sets can become so time consuming to measure that it becomes impossible to follow variations of interest such as for example effects of natural variation in fluid and gas contents, tracer tests, etc.

Aim

• The post doc project aims at advancing the understanding of DCIP surveying and monitoring in complex environments, with special focus on how to optimise:
• Electrode spreads for 3D DCIP in unrestricted and restricted site conditions
• Measurement sequences for time efficient 3D DCIP surveying
• System layout design with regard to data quality with special attention to the spectral content

Methods
The activities will include theoretical as well as practical aspects. Forward and inverse numerical modelling will thus be key tools, but measurement tests in laboratory and field will also be important parts of the study.  
The results will be presented in scientific seminars, workshops and conferences, and in peer reviewed scientific papers.

Application

Submit your full application including CV and cover letter by using the APPLYbutton.

Requirements
A PhD degree with relevant focus with respect the aim and methods outlined above is required. Fluent oral and written English language is a prerequisite, with well documented ability to author scientific papers.

Research Environment
There is an active group working on non‐destructive testing and applied geophysics at Engineering Geology. An area of special focus is DCIP surveying and monitoring, with senior and doctorate level students involved. Furthermore undergraduate students on master and bachelor levels are involved doing thesis studies on the subject.  
The activities will be closely linked with the GEOCON project in cooperation with Danish colleagues:
www.geocon.env.dtu.dk
There will also be extensive collaboration with the Geoinfra‐TRUST projects:  
trust‐geoinfra.se

Conditions
The post doc stay will be financially supported with a tax free grant for one year. If additional funding can be secured it may be possible to extend the grant one more year.