29 November 2002

Looking at the periodicity of soil gas radon

by Sam Stanifer
SAS Los Angeles Chapter

The Los Angeles Chapter continues to conduct experiments that investigate earthquake precursor signals, as we reported at last year’s SAS conference in Philadelphia. For over a year now, we have continuously monitored data from two instruments in Hank Burwash’s back yard in Los Alamitos. These instruments are RM-60 radiation monitors from Aware Electronics. We collect data from both instruments simultaneously, and Hank periodically e-mails the data files to Stan Martins, who compiles and plots the data vs. earthquake events in California.

The RM-60, as installed in Hank Burwash's greenhouse. The RM-60 is on the left, with the (coffee) filter shown next to the RM-60 window on the right side of the instrument. A low volume pump (fish tank pump) is shown on the right side of the picture. It draws air from a hole about 3 feet deep beneath the greenhouse floor, and forces air onto the filter. Radon daughter products collect on the pump side of the filter where Beta and Gamma should be detected by the RM-60. Alpha is likely inhibited, due to the daughter products collecting on the pump side of the filter. (Alpha is absorbed by the paper) The computer connection line was disconnected for the photo, and is shown as the telephone style connector with no input on the left side of the instrument. Click image to enlarge.

Low volume air is drawn from a hole about three feet deep, and collected on a filter, which is very near the window on the first RM-60. The second RM-60 is located nearby, but in a shallow depression, with no filter. The intent of this arrangement is to produce data which:

1. Would most likely reflect the radioactivity of radon daughter products captured on the filter, with minimum periodicity of the signal due to "pumping" effects of barometric and tidal forces.
2. Might show from the second RM-60, the periodicity more clearly.

The second instrument is then a "control" to see if we can isolate any signals directly related to earthquake preparation by comparing the two sets of data.

In the process of deciding upon this data collection scheme, Hank and Joe Cascarano collected data from only one instrument (without a filter), for a period of time. A study was undertaken and a small report produced. It was a joint effort, with several of us contributing to the compilation of the report. The results and conclusions were pretty interesting and now we have a better understanding of what we may be seeing in the data.

The short report of our findings can be read here: http://www.qsl.net/kj6bu

Click on "Periodicity Report".

Along the way, we find interesting stuff also. For example, this graphic has no radon data, but was collected recently from near-real time earthquake data available on the web, and put into Excel ™. It demonstrates pretty clearly what is not intuitive from other views of this data...say a map view. We see here that small earthquakes seem to appear in clusters. Often these clusters are only a few minutes or seconds apart. But as the graph shows, clusters of multiple quakes within a five-hour window occur frequently.

Click image to enlarge

 

Our next challenge is to implement a remote data collection means with Tim Dolan’s help. We plan to collect Hank’s radiation data more frequently via landline, perhaps on a daily basis, put it together with the earthquake event data, and post it to our web site. It won’t be real time, but may be a step in that direction.

We also plan to set up a second site, in the foothills North of Bakersfield. Comparison of the data from the two sites should prove pretty interesting.