Contact Information
2284 NW Thurman St.
Portland, Oregon, 97210
Voice: (503) 227-7659
Fax: (503) 227-1074

Geophysics - Vibration & Noise - Rock Mechanics

Providing Quality Geophysical Consulting Services since 1984

Magnetic Methods

Magnetic surveys can provide information useful for the following applications:

Gradiometer SurveyMagnetic surveys provide a cost-effective means for quickly providing whole-site or specific-area investigations. Magnetometers are highly portable, therefore, surveys can be conducted over uneven terrain.

A magnetic survey accurately measures the earth's magnetic field. Objects containing ferrous material create local perturbations in the earth's field.

A magnetic gradiometer consists of a magnetometer equipped with two sensors. The sensors are placed in a vertical orientation to measure the vertical gradient in the earth’s magnetic field, or they can be placed in a horizontal configuration to measure the horizontal gradient. A gradiometer is ideally suited for detection of shallow ferromagnetic material because the gradiometer accentuates the signal from objects which are at shallow depth while ignoring distant features. In a gradiometer survey, no corrections are needed for diurnal changes in the earth’s magnetic field because the diurnal changes affect both sensors equally.

Magnetic Data
Magnetic gradiometer contour plot.
Magnetic anomalies are indicated by the bright red and blue areas.  Hazardous waste drums were excavated from most of these anomalies.