KTB Borehole Measurements Data - Data collection
This data collection compiles the KTB Borehole Measurements Data of the German Continental Deep Drilling Program operated by the GFZ - German Research Centre for Geosciences. Extensive borehole measurements were performed during the active drilling phase of the KTB pilot and main hole. All KTB borehole measurements are described in detail in the Scientific Technical Report - Data 21/03 "KTB Borehole Logging Data" (Kück et al. 2021). The terms borehole measurements, downhole logging, and logging are used synonymously here.
The KTB logging data files contain the final processed versions of the geoscientific borehole logging data from logs in the two KTB boreholes:
• KTB-Oberpfalz VB (KTB Vorbohrung/Pilot Hole or KTB-VB)
• KTB-Oberpfalz HB (KTB Hauptbohrung/Main Hole or KTB-HB).
Here only the acronyms KTB-VB and KTB-HB are used. In total there are 145 logging data files from the KTB-VB and 239 logging data files from the KTB-HB. The data compilation comprises the following measurements:
• Borehole geometry and orientation logs
• Composite logs (compilation of standard logs of resistivity, gamma spectrum, density, neutron porosity, sonic)
• Geochemical logs
• Gravimetry logs
• Magnetic susceptibility and field logs
• Spontaneous potential and induced polarization (SP and IP) logs
• Structures from borehole images, foliation, fracs, faults, joints
• Temperature logs
The maximum logging depth was 4001 m in the KTB-VB and 9085 m in the KTB-HB. There is no sonic waveform data available. There is no electrical or acoustic borehole wall image data available. However, the spatial orientation of planar structures (foliation, faults, fractures, joints) gained by manual sinus structure picking from these electrical images are included.
SAFOD is motivated by the need to answer fundamental questions about the physical and chemical processes controlling faulting and earthquake generation within a major plate-bounding fault. SAFOD will drill and instrument an inclined borehole across the San Andreas Fault Zone to a depth of 3.2 km, targeting a repeating microearthquake source. The drill site is located west of the vertical San Andreas Fault on a segment of the fault that moves through a combination of aseismic creep and repeating microearthquakes. It lies at the extreme northern end of the rupture zone of the 1966, Magnitude 6 Parkfield earthquake, the most recent in a series of events that have ruptured the fault five times since 1857. The Parkfield region is the most comprehensively instrumented section of a fault anywhere in the world, and has been the focus of intensive study for the past two decades. This data set contains SAFOD borehole trajectory data.