Active Sensors

Jump to: navigation, search

Exploration Technique: Active Sensors

Exploration Technique Information
Exploration Group: Remote Sensing Techniques
Exploration Sub Group: Active Sensors
Parent Exploration Technique: Remote Sensing Techniques
Information Provided by Technique
Stratigraphic/Structural: Detect fault and ground movement, delineate faults, create high-resolution DEMS, quantify fault kinemaics, develop lineament maps, Geophysical Monitoring
Hydrological: Can give indications about subsurface geothermal fluid flow
Active Sensors:
Sensors that emit their own source of energy then measure the returned/reflected energy signature.
Other definitions:Wikipedia Reegle

Active remote sensors provide their own energy source; they emit a beam of energy directed toward a target of interest and then measure the reflected or backscattered signal. The time it takes for the signal to return is measured as well as the signals amplitude and wavelength. By measuring the time delay between the signal emission and return the location, speed, and direction of a target can be determined. Radar and LiDAR are the most commonly used active remote sensing techniques.
Use in Geothermal Exploration
In geothermal exploration active remote sensing techniques are used mainly for monitoring geothermal reservoirs before, during, and after production. Highly accurate measurements of ground deformation can be determined with active sensors and the information can be used in reservoir models to help determine the effects utilization has on the reservoir and environment. Active methods are also useful for detecting active faults and can be used in densely forested areas where faults are not obvious with other methods.
Related Techniques

Physical Properties
Basic concept of active remote sensing [1]

Best Practices
Many geothermal areas are in remote areas which are difficult to access so active remote sensing methods can be extremely valuable for gathering initial information about an area at low cost and low impact to the environment. Active remote sensing techniques are also very useful for monitoring a geothermal reservoir before, during, and after development. An advantage of active sensors is that they can be used at any time of day and don’t require any outside source. Some active sensors such as radar can penetrate cloud cover and even thick forest canopy.
Potential Pitfalls
Active remote sensing techniques can be very useful, however in order to make direct temperature measurements, collect samples, and preform most geophysical methods in situ field work is required.

  1. National Aeronautics and Space Administration. Active and Passive Remote Sensing Diagram [Internet]. 2013. [cited 2013/10/01]. Available from:

No exploration activities found.

      Print PDF