Steinitz, G., Piatibratova, O., Kotlarsky, P. Geological Survey of Israel, Jerusalem

1. a • Elat Granite: • Measured pattern • Smoothed time series - AR signal and SAR signal as an asymmetry • Modulation of the residual time series - AR and SAR signal Year 2002 2003 2004 2005 400 500 MS MD 400 DR S1 S1 200 300 S2 S2 Counts/15-minute Counts/15-minute 200 0 100 0 -200 -100 3400 3600 3800 4000 4200 4400 4600 4800 5000 Days since 1.1.1992 10000 Metal tank, tight 1999 2001 2003 2005 2007 Historgram of values (17W, Gamma detector) (air) 17W Bias 1.5e+5 5000 (Rn source) Counts 1.0e+5 0 2008 2009 2010 2011 Counts 2008 2009 2010 2011 1e+5 2e+5 3e+5 2.5e+5 Gamma Alpha Measured Nuclear radiation - summer peak times of annual signal Gamma-C 5.0e+4 1400 Long-term bias Alpha-H Annual Radon (AR) Alpha-L 2.4e+5 Temperature 30 days Long-term (MY) 1300 2.415e+5 26.5 Counts/15-min Day 1360 27.0 2500 3000 3500 4000 4500 5000 5500 2.440e+5 1200 26.4 1355 o C Alpha 2.3e+5 2.410e+5 2007 1350 26.3 o C 1355 Gamma Gamma Alpha 1100 26.8 2.435e+5 26.2 1345 Alpha-H 2.405e+5 1335 1340 Alpha-L 26.1 2008 1335 2.2e+5 1000 2002 2004 2006 2008 2010 5600 5800 6000 6200 6400 6600 6800 2.430e+5 1330 26.0 2.400e+5 1330 26.6 5600 5800 6000 6200 6400 6600 6800 5640 5650 5660 5670 5680 5690 5700 6020 6030 6040 6050 6060 6070 200 14000 Day since 1.1.1992 Day since 1.1.1992 Day since 1.1.1992 Amram 1400 27.4 2.428e+5 2004 2005 2006 2007 2008 2009 o C 12000 1400 2010 27.2 2.435e+5 Alpha 2.425e+5 S1 75 26.2 o Alpha C 100 2009 (counts) (counts) 1390 10000 Gamma Gamma 1385 27.0 2.423e+5 1380 50 Amplitude (x1000) 8000 Alpha 2.430e+5 26.0 2.420e+5 26.8 1375 Gamma 6370 6380 6390 6400 6410 6420 6430 6740 6750 6760 6770 6780 6790 6800 6810 2008 2009 2010 2011 Day since 1.1.1992 Day since 1.1.1992 0 30 25 1400 6000 25 0 gamma-C 4000 2.4e+5 S2 5000 1300 20 Counts/15-min (gamma-C) Counts/15-min (alpha) Day 4000 5000 6000 7000 o 15 C Amplitude 15 Amplitude (x1000) 2500 1200 10 2.3e+5 Gamma-C Alpha-H 10 Alpha-L Temperature 5 0 1100 0.00 0.01 0.02 0.03 0.04 0.05 5750 6000 6250 6500 6750 Cycle/day Day since 1.1.1992 0 4500 5000 5500 6000 6500 Mean of two Days since 1.1.1992 75 alpha detectors 50 Amplitude 2008 2009 2010 Spectra of alpha and gamma measurements (Experiment - 4yrs) show clear peaks characteristic for annual and semiannual periodicity (365.2 and 182.6 cycle/day). 25 Alpha H 80 0 60 0.00 0.01 0.02 0.03 0.04 0.05 Cycle/day 40 20 Roded:Multi-year variation of phase of the diurnal periodicities S1, S2 1999 2001 2003 2005 2007 2009 6 4 Alpha L 2 6 14 S1 12 phase (rad) 0 10 4 8 6 6 2 4 4 2 0 0 2 5500 6000 6500 5500 6000 6500 S2 S1 Days since 1.1.1992 Days since 1.1.1992 0 3000 4000 5000 6000 S2 S3 Days since 1.1.1992 Solar radiation tidal forcing of radon signals in subsurface air Steinitz, G.,Piatibratova, O., Kotlarsky, P.Geological Survey of Israel, Jerusalem steinitz@gsi.gov.il • The reasoning • Dominance of solar tidal frequencies of annual, and daily scale • Annual modulation of the amplitude and phase of daily and sub daily tidal frequencies • Systematic multi-year variation of signal and periodic characteristics • Occurrence different locations, at depth to >100 meter • Similar phenomena in laboratory experiments of radon in confined air • And • Negation of climatic influences • [Lack of gravity tidal frequencies] • IMPLIES • Periodicity is forced by solar tide • A component of solar radiation? Monitoringsites Geophysical background High temporal resolution monitoring of radon, using alpha & gamma detectors, is carried out at several arrays located in arid southern Israel. Monitoring, at a resolution of 15-minutes, is conducted at depths ranging from 1.5 to 120 meter. Temporal phenomena encountered differ among sites, but have similar fundamental characteristics. Radon (Rn-222) occurs at highly varying levels as a trace component in subsurface air (geogas). It is measured by alpha and gamma activity during the decay of radon and its progeny. Radon in geogas exhibits systematic temporal variations composed of periodic and non-periodic signals spanning several orders of magnitude in time – multi-year, annual to daily and sub-daily duration. Analysis of extensive data sets from key sites 200 km apart in the arid desert of southern Israel demonstrated that the periodic variations, are observed to a depth of >100 meter. A component of solar irradiation tide was suggested (References) as the driver of these periodic phenomena at depth. The issue of external forcing of radon signals was tested experimentally using alpha and gamma detectors recording radon within a confined volume of Air. The setup consisted of an isolated volume (640 L) of air with radon, the latter diffusing into the upper air volume from U bearing ground phosphorite (376 Kg). Alpha and gamma radiation emitted from radon in the tank air varies spatially and temporally. A 4-year time series shows multi-year and multi-day signals and especially periodic signals of annual and daily scale. The diurnal variations are dominated by periodicities of 24-, 12-, and 8-hours which are attributed to the Solar tidal constituents S1, S2, and S3. Periodicities indicative for diurnal gravity tide (O1, M2; Lunar influence) are clearly lacking. Profound external geophysical influence is further indicated by compounded relations that occur as annual modulation of the amplitude and phase of the diurnal constituents S1, S2 and S3. Further insight is derived from the long term variations in time series from the geological environment and from the experiment. In addition to the annual periodicity clear semiannual and ternary annual signals are demonstrated. They are attributed to the solar tidal constituents Sa, SSa and STa. • Signal types, periodicity, Solar tide components • PeriodTidal componentRn Acronym • Daily signals 24-, 12-hoursS1, S2 DR • Multi-Day (non-periodic) MD • Annual radon 365.2 days SA AR • Semi-annual radon 182.6 days SSA SAR • Ternary annual radon 121.7 days STA TAR • Multi-Year (non-periodic?) MY Radon monitoring arrays along the Dead Sea Rift (DSR) • NW Dead Sea • Array of stations, along a20 km sector • 1.5 m deep in unconsolidated gravel 17W 21W Periodograms of the diurnal components of radon signals in subsurface air Solar irradiance related components - S1, S2 dominate = solar tide Gravity tide - rare The multi-year rising trend observed at Experiment, 17W and Amram sites. The temporal pattern is measured by alpha and gamma detectors in Amram and in the Experiment. • Intraplate • Depth: 1.2 m & 90 meter • Massive syenite GAV Amram Roded Elat Granite • Southern Arava • Array of stations, 20 km sector • In Precambrian basement rocks • Depth 2 to +100 meter Granite; Elat; 54m NW Gulf Elat, Rn in seawater Shore gravel; 2m deep, 130 days Gravel; NW Dead Sea; 1.5m Granite; Elat; 54m Experimental replication Roded:Annual variation of amplitude of the diurnal periodicities S1, S2 1999 2001 2003 2005 2007 2009 150 S1 AR 100 50 Amplitude 0 100 S2 50 Semi-annual radon signals are superimposed on the annual signal recorded by alpha-L and gamma-C. A similar semi-annual pattern is absent in the ambient temperature. 0 3000 4000 5000 6000 Days since 1.1.1992 Spectra for alpha and gamma measurements (9 yrs) show clear peaks characteristic for annual and semi-annual periodicity (365.2 and 182.6 cycle/day). • Smoothed pattern of • AR & SAR signals • (maxima of T – lags) GAV:Daily averages at 1.2 meter Amplitude and phase are extracted by applying FFT windowing, where each point represents a (consecutive) 21-day time interval. 2003 2004 2005 2006 2007 2008 1000 Phase Amplitude Daily mean (counts) 500 2008 2009 2010 Spectral analysis: SA. SSA, STA periodicities 6 0 5 4 GAV:Annual modulation of the amplitude of the diurnal periodicities S1 and S2 2 1 150 S 1 Gamma C S 7 2 CWT analysis: Annual modulation of the amplitude of DR signal (S1 and S2) occurs as a compounded feature 100 6 10 amplitude Phase (rad) Amplitude (counts x103) 50 5 2 0 2003 2004 2005 2006 2007 2008 0 • REFERENCES • Steinitz, G., O. Piatibratova, and S. M. Barbosa, 2007. Radon daily signals in the Elat Granite, southern Arava, Israel, J. Geophys. Res., 112, B10211, doi:10.1029/2006JB004817. • Steinitz, G., Piatibratova, O., 2010a. Radon signals in the Gavnunim intrusion, Makhtesh Ramon, Israel. Geophys. J. Int. 180, 651–665. • Steinitz, G. and Piatibratova, O., 2010. Radon signals at the Roded site, Southern Israel, Solid Earth, 1, 99-109, doi:10.5194/se-1-99-2010. 21W: Annual and semi-annual modulation of the amplitude of the diurnal periodicities S1 and S2 • Annual modulation of the periodic components (amplitude & phase) of the DR signal in Experiment. • Annual variation of the amplitudes of the daily components is dissimilar for gamma and alpha time series - showing opposite temporal patterns!