Map of locations where more than 7,000 borehole geophysical logs are currently available at about 1,700 sites in the GeoLog Locator web application.


Reston, Va. — Digital borehole geophysical logs and related data files are now easily accessible through GeoLog Locator (!/) a new web-based, map view and retrieval tool developed by the U.S. Geological Survey.

This tool releases more than 7,000 digital borehole geophysical logs at over 1,700 locations to the public — many for the first time. Users like hydrogeologists, groundwater hydrologists and geologists can search and explore the online database, which primarily includes information collected by the USGS, as well some data compiled from other sources with permission.

“I have been test driving the new GeoLog Locator web application for a few days, and it will undoubtedly prove an incredibly useful tool for geologists and hydrologists seeking downhole geophysical logs for boreholes at our facility, and elsewhere,” said Jeffrey Forbes, a hydrogeologist specializing in environmental restoration at Fluor Idaho. “The map feature is very user friendly, and I’ve had no problems locating the wells and boreholes of interest. Hats off to the USGS for creating yet another powerful online tool to make geoscience information and data readily available to everyone!”

At the map interface, users can zoom and click on individual borehole locations to view and download available logs. The interface is fully searchable by state, county, USGS National Water Information System, or NWIS, site number or station name, or by using a geographic bounding area. Users can search by log criteria, such as log category (generally logging tool type), file format, minimum logging depth, or log collection date range. Logs can be downloaded in batches that result from search criteria or can be downloaded individually.

A wide range of borehole log types are available, including acoustic, caliper, electric, electromagnetic, fluid, lithologic, nuclear, optical, well construction, or a combination or composite of these types. File formats include ASCII, DOC, IMG, LAS, PDF and original. Where possible, geophysical logs are available in Log ASCII Standard (LAS) v2.0, a format developed by the Canadian Well Logging Society. The LAS format is a widely accepted standard for storage and transmittal of log data in the geophysical and groundwater science community. Image logs typically are exported in other formats where features can be delineated. As new logs become available, they will be added to the database.

Borehole geophysics is the science of recording and analyzing measurements of physical properties made in wells or test holes. Borehole geophysical logging is a procedure to collect and transmit specific information about the geologic formations penetrated by a well by raising and lowering a set of probes that contain watertight instruments in the well. Borehole geophysics is used in groundwater and environmental investigations to obtain information on well construction, rock lithology and fractures, permeability and porosity, and water quality.