Deep Fault Drilling Project — Alpine Fault, New Zealand
Shallow borehole and surface materials working group
General Information
The following is a revised and updated version of information sent via email to participants in the working group on 9 April 2009. Further updates are necessary!
Aims of working group
- Drill shallow boreholes (<200m ?) across the Alpine Fault into the footwall rock:
a. To investigate the technical issues involved in drilling and preserving the fault zone materials, such as borehole stability, borehole deviation, core recovery, and to establish protocols for distribution of core to interested parties
b. To collect continuous, unweathered core across the fault zone (including footwall) for the physical properties studies outlined below
c. To provide shallow boreholes that can be instrumented / logged
- Investigate the physical properties of fault zone materials from shallow cores and surface materials
a. Measurements in surface materials:
Density, seismic velocities, porosity, permeability, electrical conductivity, microstructural characterisation (including… brittle fault rock and gouge on recent or past principal slip surfaces: particle size distributions, shape distributions, anisotropy, fracture density and orientation in damage zone; ductile fault rock: textures, porosity structure, water content, veins (from the ductile to brittle domain) density, orientation, geometry, internal structures, infilling,?fluid inclusions), macrostructural characterization of the geometry of present and past principal slip zones and of fracture density and orientation in the damage zone, chemical characterisation (brittle and ductile fault rock mineralogy), rock mechanics testing (frictional properties, strength, ductility), thermochronology
b. Measurements in core:
Density, seismic velocities, porosity, permeability, electrical conductivity, microstructural characterisation (including brittle fault rock particle size distributions, shape distributions, anisotropy, fracture density and orientation in damage zone, and ductile fault rock textures, porosity structure, water content), chemical characterisation (brittle and ductile fault rock mineralogy), structural characterisation (use CAT-scanning techniques, desirably with sub-mm resolution), rock mechanics testing (frictional properties, strength, ductility)
c. Down-hole logging and monitoring:
In situ permeability (Pf and flow rates), heat flow, fluid monitoring, microseismicity, f.z. guided wave studies (?), seismic anisotropy, structural characterisation through photographic and imaging, stress, gamma-wave, resistivity/other electrical methods(?)
Personnel
University of Otago has already provided considerable staff time input, and will continue to provide staff time to managing core retrieval and logging, provided research funds are available for this project.
IESE, University of Auckland: Cost sharing (i.e. salary) for staff (Mike Hasting) involved in drilling supervision (and instrumentation?).
Martha Savage – will provide an interface between seismologists and structural geologists and will obtain a student (MSc?) to work on the seismic aspects of characterization of seismic anisotropy in a shallow borehole.
Klaus Regenauer-Lieb – has a Postdoc who can do synchrotron x-ray microtomography work on existing samples of surface materials and seismic data processing – only this year?
Anne-Marie Boullier – able to work with microstructures of samples from surface outcrops and core during sabbatical visit Sept 2010-Feb 2011.
Plans and work in progress
We have transferred this information to the table on the main working groups page. Please contact Virginia Toy if you want to add anything to this table.
