12:15 PM - 12:30 PM
[MIS32-13] Deep Fault Drilling Project, Alpine Fault, New Zealand
Keywords:Fault Zone Drilling, Alpine Fault
An open hole with depth of 893.18 m was drilled without coring during the DFDP-2. The drilling revealed the several features of the hanging wall of the Alpine Fault. The thickness of quaternary sediments at the Whataroa River is about 240 m. Cutting samples were collected with interval of 2 m and the microstructural changes within the fault zone were revealed. Geophysical wire-line loggings were carried out. The result of temperature logging indicates that the geothermal gradient in the hanging wall is as high as 100 ℃/km.
Water level, density, viscosity and other properties of mud water were continuously monitored, which are expected to constrain the hydrological property of fault zone.
DFDP-2 unfortunately failed to get the drill-core samples and penetrate the Alpine fault due to several problems during drilling. One of the objectives of DFDP-2 was to reveal fault behavior at depth and core-log integration is essential. However it is impossible to achieve this. The Alpine fault is a unique and scientifically intriguing fault, and it is worth being drilled again at the Whataroa River. A strategy for succeeding at the drilling should be important.