Multi-offset, single-hole, borehole-radar reflection surveys were conducted at the U.S. Geological Survey Fractured Rock Research Site at Mirror Lake, in Grafton County, New Hampshire. The study was conducted to evaluate the benefits of applying multi-offset seismic processing techniques to borehole-radar reflection surveys in fractured rock. The multi-offset reflection surveys were conducted i...

Borehole radar can be used in a single-hole reflection mode or in a cross-hole tomography mode. In the reflection mode, radar provides an image of discontinuities in the bedrock surrounding a borehole, including bedding planes, lithologic contacts, fractures, and cavities. The measurements are either directional or omnidirectional, depending upon the type of equipment and antennas. In the tomog...

Near a borehole, stress concentration effects may cause a complex spatial variation of elastic anisotropy. Stress-induced sonic anisotropy results when moduli and velocities are stress dependent and the state of stress is nonhydrostatic. For such cases, the appropriate material model is that of an elastic orthorhombic medium with material axes aligned with the principal axes of stress. We simul...

[1] Integrated Ocean Drilling Program (IODP) Hole 1301A was drilled, cased, and instrumented with a long‐term, subseafloor observatory (CORK) on the eastern flank of the Juan de Fuca Ridge in summer 2004. This borehole is located 1 km south of ODP Hole 1026B and 5 km north of Baby Bare outcrop. Hole 1301A penetrates 262 m of sediment and 108 m of the uppermost 3.5 Ma basaltic basement in an are...

Barometric pressure changes can induce airflow in an open borehole or well screened in the vadose zone, thereby ventilating the soil surrounding the borehole. This paper presents an analytic model of the induced airflow and compares the predictions of the model with experimental measurements. This model may be useful for the design of passive soil vapor extraction as applied to the remediation ...

Advances in virtual globes and Keyhole Markup Language (KML) are providing the Earth scientists with the universal platforms to manage, visualize, integrate and disseminate geospatial information. In order to use KML to represent and disseminate subsurface geological information on virtual globes, we present an automatic method for modeling and visualizing a large volume of borehole information...

A suite of surface and basal measurements during and after borehole drilling is used to perform in situ investigation of the local basal drainage system and pressure forcing in western Greenland. Drill and borehole water temperature were monitored during borehole drilling, which was performed with dyed hot water. After drilling, borehole water pressure and basal dye concentration were measured ...

Crossover of the dispersion of flexural waves recorded in borehole cross-dipole measurements is interpreted as an indicator of stress-induced anisotropy around a circular borehole in formations that are isotropic in the absence of stresses. We have investigated different factors that influence flexural wave dispersion. Through numerical modeling, we determined that for a circular borehole surro...

Measuring the electrical field induced by a borehole Stoneley wave is a new method for characterizing a rock formation around a borehole. Our field measurements demonstrate that the Stoneley-wave-induced electrical field can be detected in sedimentary rocks (dolomite in our experiment), and that the amplitude of this electroseismic phenomenon can be used to detect isolated fractures and permeab...

For a robust way of estimating time shifts near horizontal boreholes, we have developed a method for separating the reflection responses above and below a horizontal borehole. Together with the surface reflection data, the method uses the direct arrivals from borehole data in the Marchenko method. The first step is to retrieve the focusing functions and the updown wavefields at the borehole lev...