Authors:M. Zoran, R. Savastru, D. Savastru, C. Chitaru, L. Baschir, and M. Tautan
South-Eastern part of Romania has a highest potential seismic risk in Europe due to the earthquake-prone Vrancea zone placed
at conjunction of four tectonic blocks in the South-Eastern part of Carpathian Arc. This paper is an attempt to analyze the
development of radon pre-earthquake anomaly in relation with moderate seismic events in Vrancea area through permanent monitoring
with solid state nuclear track detectors CR-39 detectors. Radon in air above the ground was measured during 1 year period
(November 2010–October 2011) in four selected test sites: Vrancioaia (VRI) and Plostina (PLOR) located in Vrancea zone, and
Muntele Rosu-Cheia and Bucharest. During sampling period recorded earthquakes that occurred mostly in Vrancea epicentral region
were minor-moderate of moment magnitudes in range of
. The average radon concentration in air above the ground measured with CR-39 detectors and 10 days period recorded simultaneously
at all test sites, registered the following values: (1) in Vrancea area (similar in VRI and PLOR) was 1094.58
130 Bq/m3). Clear radon anomalies, mostly at VRI and PLOR in Vrancea epicentral area as well as at Muntele Rosu-Cheia have been measured
before seven minor earthquakes which were recorded in the range of moment magnitude
in Vrancea area. Temporal variation of radon in air near the ground have been examined in relation with meteorological parameters
like as air temperature, relative humidity, air pressure and wind velocity. Permanent monitoring of radon concentration anomalies
in seismic area Vrancea is an important issue as surveillance tool in the field of earthquake hazard for Romania.
Gamma-ray intensities were measured of the ground on an eastern part of the Kobe urban area, where a strong earthquake occurred in January 1995 killing 6000 people, in order to investigate hidden faults and its relation to the damage of constructions. Several linear alignments of relatively high -ray intensity points were detected and at least some of them are considered to be ascribed to small-scale faults. It can be pointed out that the localities of such high -ray alignments are almost in accordance with those of relatively highly damaged zones. However, a long and distinct high -ray alignment as expected for a large fault which runs through the heavy damage belt does not exist beneath the area, supporting non-fault origin for the overall heavy damage belt.
The original purpose of this investigation started in 1996 was to study the radiological impact on the local population of
the village of Chichiviriche de La Costa. But, soon after the major earthquake (Ms=6.8) in the state of Sucre on July 9, 1997,
the objective was changed to study the fluctuation of radon (222Rn) to see if it could be correlated to seismic activity and/or if the amonlous change just before the earthquake can be considered
a precusor for it. Measurements of222Rn by simply de-gassing about 250 ml of natural thermal water employing a Pylon AB-5 radiation monitor and counting the radiation
after it reached equilibrium were performed. The values for four sampling periods in the first half of 1996 were about 17
Bq/l of222Rn, a month before the earthquake they were less than 15 Bq/l and increased about 70% to 25 Bq/l two days before the seismic
event. In about two weeks, they returned to about 18 Bq/l. But, surprisingly, they have gradually increased to about 35 Bq/l,
before leveling off at about 27 Bq/l.
Authors:J.J. LaBrecque, P.R. Cordoves, P.A. Rosales, F. Audemard, and G. Romero
Immediately, after the July 9, 1997 earthquake (Ms = 6.8) in the state of Sucre, Venezuela, we began measuring radon in water to investigate the possible correlations with the seismic activity and to study the meteorological affects. Sampling periods were for 3–5 days with 4–8 weeks in between each. During the first two sampling periods, the seismic activity was high with several minor events (Mb4.0) and anomalous radon concentrations were measured and considered as possible precursors for the events. We have also shown that the radon activity was stable except for daily meteorological effects during periods of low seismic activity. The radon activity during the first year after the major event on July 9, 1997, at the beginning of the rainy season increased from about 50 pCi/l to about 350 pCi/l for all sampling points. Then abruptly dropped to 100 pci/l at the beginning of the next rainy season for points #1 and #2 in the Casanay river and stayed relativelystable during the second year. At the start of the third year, the values began to increase again, similarly to the first year. We concluded that this was caused by the heavy rainfall at the beginning of the rainy season. While at the sampling points at Hotel Cristal, thermal spring pool, it decreased slowly during the second year but increased again at the onset of the third year. Finally, we have concluded as other investigators, that monitoring radon activity alone is insufficient to predict minor earthquakes (Mb4.0), but in some cases it can be considered as a precursor.
The uranium content of the thermal waters in the Chepino valley was determined in a period of increased seismic activity.
Significant changes in the uranium concentration, much above the normal background values were established. In one group of
water sources a well-expressed synchrony in the uranium content variations is observed and the maximum is reached about 1.5–2
months after the initial strong seismic shock.
Authors:W. Plastino, G. Panza, C. Doglioni, M. Frezzotti, A. Peccerillo, P. De Felice, F. Bella, P. Povinec, S. Nisi, L. Ioannucci, P. Aprili, M. Balata, M. Cozzella, and M. Laubenstein
The ability to predict earthquakes is one of the greatest challenges for Earth Sciences. Radon has been suggested as one possible
precursor, and its groundwater anomalies associated with earthquakes and water–rock interactions were proposed in several
seismogenic areas worldwide as due to possible transport of radon through microfractures, or due to crustal gas fluxes along
active faults. However, the use of radon as a possible earthquake’s precursor is not clearly linked to crustal deformation.
It is shown in this paper that uranium groundwater anomalies, which were observed in cataclastic rocks crossing the underground
Gran Sasso National Laboratory, can be used as a possible strain meter in domains where continental lithosphere is subducted.
Measurements evidence clear, sharp anomalies from July, 2008 to the end of March, 2009, related to a preparation phase of
the seismic swarm, which occurred near L’Aquila, Italy, from October, 2008 to April, 2009. On April 6th, 2009 an earthquake
(Mw = 6.3) occurred at 01:33 UT in the same area, with normal faulting on a NW–SE oriented structure about 15 km long, dipping
toward SW. In the framework of the geophysical and geochemical models of the area, these measurements indicate that uranium
may be used as a possible strain meter in extensional tectonic settings similar to those where the L’Aquila earthquake occurred.
Due to the subcrustal earthquakes located at the sharp bend of the Southeast Carpathians, Vrancea zone in Romania has a high
potential seismic hazard in Europe. Among several seismic precursors, radon anomalies in air, ground, and groundwater in the
epicentral areas can be associated with the strain stress changes that occurred before and after earthquakes. In order to
support this theoretical view, the main aim of this paper was to investigate temporal variations of radon concentration levels
in air near the ground and in ground air by the use of solid state nuclear track detectors CR-39 and LR-115 in relation with
some seismic events at two seismic stations Vrancioaia and Plostina, located in Vrancea active region. This paper reports
essentially the observation of radon concentration levels in the air near the ground at 1 m height for the earthquakes that
occurred during the period of November 2010–October 2011 and moment magnitudes Mw in the range of
. The average radon concentration in air above the ground measured with CR-39 detectors recorded for 1 year period in Vrancea
area was 1,094.58 ± 150.3 Bq/m3 and 10 days fluctuations were placed in the range of 129 ± 40 Bq/m3 and 5,888 ± 700 Bq/m3. Also have been reported measurements of in soil radon concentrations in drill holes at 0.5 m depths during period of March
1977–October 1980, just after 4 March 1977, Mw 7.4 Vrancea earthquake. The knowledge of air–ground–gas 222Rn anomalies is very important for earthquake pre-signals assessment as well as for precisely location of geologic active
Authors:O. Baykara, M. İnceöz, M. Doğru, E. Aksoy, and F. Külahcı
On-line monitoring of soil radon (222Rn) concentration system was constructed on one of the main active fault zone of East Anatolian Fault System (EAFS) in Turkey.
The preliminary results, observed during the second part of 2004 and first part of 2005 is presented. During the monitoring
of soil radon concentration, numerous anomalies that equal or twice standard deviation were observed. In addition, the variation
of the radon concentration was examined between the mean values and plus/minus two standard deviations and any increase in
radon concentration above this limit was assumed to be 222Rn anomalies. These anomalies usually appeared between a few days or weeks before the earthquakes occurrence. The obtained
data were also compared as considered respect to the earthquakes occurred in a 100 km radius of the fault system.
Greater than anticipated activity from the á - and â -emittingradionuclides 230Th+226Ra, 210Po, and 210Pb was observed in solution during modification of an air sampler1 to improve the sensitivity of measuring airborne radioactivity. Typicalactivities ranged from several mBq to 15Bq. We use the term geoaerosols2to describe the particles' unique transport and propose a distinct quantumphenomenon mechanism to explain the radiation accumulation. If confirmed bysubsequent experiments, the technique has potential for many practical applicationssuch as locating faults or fractures, earthquake prediction, mineral and energyresource exploration, verification of underground nuclear testing, and refiningrisk estimates from environmental exposure to particles.
Testing of two methods novel to ultrasonic measurements was carried out on cheese samples to estimate the Time-of-Flight (TOF) parameter. The Short Time Average/Long Time Average (STA/LTA) method and the Autoregressive Akaike Information Criterion Picker (AR-AIC picker) method are used mainly in seismology for earthquake event detection. The STA/LTA method proved to be ineffective with such noise level that is present during ultrasonic measurements, but the AIC picker algorithm yielded reliable results. A new approach for classification was tested on two types of samples, those were matching in composition, but different in treatment and texture. The method used is based on the results of wavelet decomposition, and after retrieving sufficient spectral data, a linear discriminant analysis (DA) resulted in 100% correct classification, which was compared to the DA classification results based on other methods.