405 documents found in 347ms
# 381
Leven, Martin • Steveling, Erich
Abstract: A quasi-continuous magnetic log has been obtained in the Hawaii Scientific Drilling Project 2 (HSDP-2) between 600 m and 1800 m, which corresponds to a time interval of approximately 350 ka to 480 ka. A tri-axial borehole magnetometer was employed to measure the horizontal and vertical magnetic fields. Measurements were taken in downhole and uphole runs, with a good correlation between the two. In a first step the logs were corrected for the transfer function of the employed low-pass filter and then for the logging depths. To calculate rock magnetizations from magnetic components, we used a multidisk cylindrical model for the penetrated rocks. The disk thickness corresponds with 0.1 m to the logging sampling rate. Magnetic borehole logging in the HSDP-2 hole has established the following: Massive lava flows can be distinguished from those with prevailing hyaloclastites and enables us to supplement the lithology, especially in depth intervals with poor core recovery.
# 382
Leven, Martin • Steveling, Erich
Abstract: A quasi-continuous magnetic log has been obtained in the Hawaii Scientific Drilling Project 2 (HSDP-2) between 600 m and 1800 m, which corresponds to a time interval of approximately 350 ka to 480 ka. A tri-axial borehole magnetometer was employed to measure the horizontal and vertical magnetic fields. Measurements were taken in downhole and uphole runs, with a good correlation between the two. In a first step the logs were corrected for the transfer function of the employed low-pass filter and then for the logging depths. To calculate rock magnetizations from magnetic components, we used a multidisk cylindrical model for the penetrated rocks. The disk thickness corresponds with 0.1 m to the logging sampling rate. Magnetic borehole logging in the HSDP-2 hole has established the following: Massive lava flows can be distinguished from those with prevailing hyaloclastites and enables us to supplement the lithology, especially in depth intervals with poor core recovery.
# 383
Buysch, Arno • Pechnig, Renate • Wohlenberg, Jürgen • Kück, Jochem • Harms, Ulrich
Abstract: The GFZ Potsdam started a log interpretation study in cooperation with the Technical University of Aachen. As a first result, the logged profile allows for a subdivision of the lithological profile into at least two major zones: (1) a subaerial zone (1900-3600ft) and (2) a submarine zone (3600-6100ft). In addition, the geophysical measurements indicate a further subdivision into the Log Units 1-4 , each unit distinguished by different geophyshical log responses: (Fig.2) (Fig.4) The basaltic lava flows of the first unit (Log Unit1), consisting of Aa-and Pahoehoe-Lavas, show high total GR and low resistivity values in general. These flows do not only reveal large variations in resistivity and gamma ray activity between different flow types but also within single lava flows. This internal variation seems to be controled by vesicularity and alteration of the single lava flows. High total GR values appear in rocks with low olivine content and sparse vesicularity.
# 384
Buysch, Arno • Pechnig, Renate • Wohlenberg, Jürgen • Kück, Jochem • Harms, Ulrich
Abstract: The GFZ Potsdam started a log interpretation study in cooperation with the Technical University of Aachen. As a first result, the logged profile allows for a subdivision of the lithological profile into at least two major zones: (1) a subaerial zone (1900-3600ft) and (2) a submarine zone (3600-6100ft). In addition, the geophysical measurements indicate a further subdivision into the Log Units 1-4 , each unit distinguished by different geophyshical log responses: (Fig.2) (Fig.4) The basaltic lava flows of the first unit (Log Unit1), consisting of Aa-and Pahoehoe-Lavas, show high total GR and low resistivity values in general. These flows do not only reveal large variations in resistivity and gamma ray activity between different flow types but also within single lava flows. This internal variation seems to be controled by vesicularity and alteration of the single lava flows. High total GR values appear in rocks with low olivine content and sparse vesicularity.
# 385
Dannowski, Grit • Schrötter, Jörg • Erbas, Kemal • Förster, Andrea • Huenges, Ernst
Abstract: The temperature pattern is attributed to a superposition of thermal and hydraulic processes. In the deeper borehole (HSDP-2, depth 3.1 km) detailed temperature monitoring was performed. Temperature measurements reveal two different thermal regimes. The upper part is characterised by cold temperatures and a negative temperature gradient similar to those observed in the shallow pilot borehole. Below 1100 m, increasing temperatures are observed. Different processes, such as topographically driven groundwater flow, ingress of salt water and conductive previous termheatnext term flow are investigated by numerical modeling. A pure conductive scenario fails to match the temperature measurements, implying that both borehole sections are overprinted by advective conditions. Coupled fluid and previous termheatnext term flow modeling with solute transport yield results that agree with observed temperatures. These data were taken at 07/02/1999 from 09.45 a.m. to 10.00 p.m.
# 386
Dannowski, Grit • Schrötter, Jörg • Erbas, Kemal • Förster, Andrea • Huenges, Ernst
Abstract: The temperature pattern is attributed to a superposition of thermal and hydraulic processes. In the deeper borehole (HSDP-2, depth 3.1 km) detailed temperature monitoring was performed. Temperature measurements reveal two different thermal regimes. The upper part is characterised by cold temperatures and a negative temperature gradient similar to those observed in the shallow pilot borehole. Below 1100 m, increasing temperatures are observed. Different processes, such as topographically driven groundwater flow, ingress of salt water and conductive previous termheatnext term flow are investigated by numerical modeling. A pure conductive scenario fails to match the temperature measurements, implying that both borehole sections are overprinted by advective conditions. Coupled fluid and previous termheatnext term flow modeling with solute transport yield results that agree with observed temperatures.
# 387
Dannowski, Grit • Schrötter, Jörg • Erbas, Kemal • Förster, Andrea • Huenges, Ernst
Abstract: The temperature pattern is attributed to a superposition of thermal and hydraulic processes. In the deeper borehole (HSDP-2, depth 3.1 km) detailed temperature monitoring was performed. Temperature measurements reveal two different thermal regimes. The upper part is characterised by cold temperatures and a negative temperature gradient similar to those observed in the shallow pilot borehole. Below 1100 m, increasing temperatures are observed. Different processes, such as topographically driven groundwater flow, ingress of salt water and conductive previous termheatnext term flow are investigated by numerical modeling. A pure conductive scenario fails to match the temperature measurements, implying that both borehole sections are overprinted by advective conditions. Coupled fluid and previous termheatnext term flow modeling with solute transport yield results that agree with observed temperatures.
# 388
Dannowski, Grit • Schrötter, Jörg • Erbas, Kemal • Förster, Andrea • Huenges, Ernst
Abstract: The temperature pattern is attributed to a superposition of thermal and hydraulic processes. In the deeper borehole (HSDP-2, depth 3.1 km) detailed temperature monitoring was performed. Temperature measurements reveal two different thermal regimes. The upper part is characterised by cold temperatures and a negative temperature gradient similar to those observed in the shallow pilot borehole. Below 1100 m, increasing temperatures are observed. Different processes, such as topographically driven groundwater flow, ingress of salt water and conductive previous termheatnext term flow are investigated by numerical modeling. A pure conductive scenario fails to match the temperature measurements, implying that both borehole sections are overprinted by advective conditions. Coupled fluid and previous termheatnext term flow modeling with solute transport yield results that agree with observed temperatures. These data were taken at 07/05/1999 from 02.30 a.m. to 07.30 a.m.
# 389
Förster, A. • Hötzl, H. • Rettenmaier, D. • Kück, J.
Abstract: Several geophysical logs were obtained in 2002 in the AIG10 borehole. One set of logs (FMI, UBI, and DSI) were measured by Schlumberger in the deep, open-hole part of the borehole (Daniel et al., 2004; Prioul et. al., 2004). GFZ and ICDP OSG performed two logging campaigns with GFZ standard logging tools (Mud Parameter, SGR, GR-BCS-DIL and MSFL). The first campaign covered the section to a depth of 708 m (depth of casing), the second campaign covers the entire borehole to 1001 m (total depth). In May 2003, a third campaign was conducted by GFZ and IPGP, which included the measurement of a temperature log with GFZ's Distributed Optical Fibre Temperature Sensing (DTS) system.
# 390
SAFOD
Abstract: 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 open hole geophysical wireline logging data from 1744-1932m (rel. to rig floor, 9,45m abv gnd)
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