SuperGrad – FAQ: Integrating Radon Measurments with SuperGrad

Increasingly, researchers are looking in to the applications of magnetics alone or in combination with seismic or radon measurements for earthquake research. GEM’s new SuperGrad technology is the highest sensitivity gradiometer ever developed for these types of applications. As an option, GEM integrates SuperGrad and Radon systems into a single research package for multi-disciplinary data acquisition and analysis.

Below is a set of commonly asked system-related questions about the Integrated SuperGrad/Radon system.

What types of data can the SuperGrad be integrated with?
What are the advantages of the SuperGrad/Radon method?
Where can it be used (i.e. national, regional, urban)?
Where has the SuperGrad been used experimentally?*
What are the results?
What conditions are required for optimal results?

What types of data can the SuperGrad be Integrated with?

To date, SuperGrad results are being integrated with Radon monitoring data from the Dead Sea Rift, Israel. This combination was chosen because of the correlations between radon anomalies and major earthquakes, and the opportunity to use ultra sensitive magnetic data to complement radon results.

With radon, there is a body of literature, including papers such as “Radon Monitoring for Earthquake Prediction in South Central Taiwan by Chyi, L. L., et. Al., 2001” that show the presence of spike-like anomalies prior to earthquakes. Another paper, “A Statistically Significant Relation between Rn Flux and Weak Earthquakes in the Dead Sea Rift Valley” provides data that is applicable to the SuperGrad installation currently in operation.

In this latter study, “Detailed monitoring of Rn flux in gravel was carried out for a period of 8 years near the active Dead Sea rift fault. The temporal relationship between hundreds of weak earthquakes (4.6 ≥ M ≥ 0) and Rn flux signals were tested for time intervals related to the start time of 110 Rn flux signals. Earthquakes located within the three pull-apart grabens of the Dead Sea rift valley were found to preferentially occur within the first 3 days after the start time of 110 Rn anomalies.

A similar relationship was not found in the 2 weeks preceding or following the start time of the Rn anomalies for earthquakes occurring within the Dead Sea rift in structurally higher segments, nor out of the Dead Sea rift.”

Accordingly, we view a combination of ultrasensitive gradiometric and radon monitoring as a new and complimentary approach to jointly investigating and monitoring these phenomena with datasets that are independent (but related). This concept has been combined into a method designated as the Integrated SuperGrad/Radon (ISGR) method that includes two sets of instrumentation systems. ISGR is now available for commercial application.

Other future approaches may be to combine the ISGR with crustal deformation measurements including creepmeters, tensor strainmeters, dilatational strainmeters and water level monitors as implemented by the U.S.G.S. in the Parkfield Area, Northern California.

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What are the Advantages of the SuperGrad/Radon Method?

The ISGR is a new type and unique, integrated instrumentation package capable of recording very high volume data from proceses and events occurring in the crust at deep and shallow levels. These new types of data will augment data from seismic and GPS sources.

The main benefit is that the system delivers independent data from other sensors (parameters) that is extremely sensitive and that may provide a clue in to the processes that are related to geohazards. Ultimately, the system provides a valuable resource of data to assist in data fusion, analysis, research and potentially, development of early warning methodologies.

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Where can it be used (i.e. National, Regional, Urban)?

The ISGR is suitable for both national and regional environments.

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Where has the SuperGrad been used Experimentally?

The Integrated SuperGrad/Radon (ISGR) technology from GEM / ISORAD has been used experimentally in the following contexts:

SuperGrad technology developed over the past ten years by GEM Advanced Magnetometers. GEM is the sole technology owner and SuperGrad is a demonstrated and unique technology that has been running at a Geological Observatory in Israel since July 2002. In its first year and 3 months of operation, the system has acquired over 5.25 billion readings – the highest sampling of magnetic data acquired by any organization to date over this type of timeframe.
Commercial radon system. Configuration of the final system is currently underway based on tests in Israel and in Halifax, Canada (July and August, 2003).

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What are the Results?

So far, the SuperGrad has generated ultrasensitive gradiometric results dating from July 2002. A full record of data is available for renew … initial results show a sensitivity of 0.1 pT which is modulated by weak diurnals due to the surrounding rocks (i.e initial setting is in a tunnel-type installation) Diurnals can be suppressed only at the expense of background noise that climbs to 1 pT peak-to-peak or about 0.25 pT root mean square (rms).

Results have been compared with those from a GEM dIdD instrument that measures changes in declination, and X, Y and Z components. The dIdD measurements indicate that there is a variation in declination – likely due to inhomogeneities in the local rocks. This will affect SuperGrad measurements.

Currently, the Israeli team members are planning to install a second system in more ideal conditions. A third system is planned for initial installation in Canada to further illustrate the effectiveness of the system for its stated objectives.

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What Conditions are Required for Optimal Results?

For optimal results, the system should be sited with sensors in a magnetically quiet region close to the fault system under investigation. Israeli partners recommend consultation with the geological team who are most familiar with the geology to most effectively site the sensors.

In addition, the sensors should be sited in an enclosed structure and immobilized to ensure repeatability of data throughout the monitoring period.

Also, decisions must be made regarding the number of sensors to be used (3 or 4) and their baseline distances.

For more Information

For more information on Potassium technologies, please refer to the technical papers on this site. Specifications on the SuperGrad are provided in the GSMP-20S3 brochure. In addition, you may want to refer to:

SUPER GRADIOMETER INFORMATION:

If you would like information specific to your work, please visit our Quotations area and submit a Request for Quotation. We would be delighted to provide you with a no-obligation quote suited to your exact needs.

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