Recently I have been experimenting with a simple system to detect the ELF/ULF magnetic radiation band. It was used to confirm readings from a fluxgate magnetometer. Anyhow, the data produced tantalizing results that may be precursors to distant quakes. It seemed to produce readings for big quakes at depths greater than 33 km. As always the S/N ratio wasn't very good. A new coil was constructed with 100,000 turns and a design, so as to modify the core material. It should be point out that Mr Charlie Plyler has been working on the ELF quake precursor detection. His site is at http://www.elfrad.com In Larry's PSN event folder are two file 000814a.au3, 000814a.au4. These files are 8 hours long from 16:00 hours UTC on the 14/8/00. Note the Ms 5.4 D'Entrecasteaux island quake at 14/8/00 at 22:11:18.1 ( 9.4S 154.2E 33km) in the file 000814a.au3. The file 000814a.au4 is the ULF magnetic background that appears to show a quake precursor 78 minutes before the event. Also a there is a strong change in the field shortly before the quake. The ELF/ULF data was 0.05Hz low pass filtered. Since the new coil has been working for only a day or so, there are no real statistics to prove or disprove the possibility that big distant quakes can be detected with this coil. Charlie Plyler's system has been running for a while and shows some amazing results. I will continue the monitoring. Cheers Arie __________________________________________________________ Public Seismic Network Mailing List (PSN-L)
Larry Cochrane <cochrane@..............>