Open Access Short Research Article

A Practical Method for Short-term Earthquake Prediction Using Multiple High-frequency Tremor Events

Yukio Fujinawa, Yoichi Noda, Minako Miyagawa, Yoshifumi Katsuta, Isao Oosumi

Asian Journal of Physical and Chemical Sciences, Page 15-24
DOI: 10.9734/ajopacs/2022/v10i3182

The substantial damage induced by major earthquakes requires the preparation of prevention methods before serious shocks occur. For a half-century, researchers have tried to develop an efficient method for earthquake prediction using modern scientific methods without practical results except for two rare successes; as a result, the general evaluation is pessimistic. Among many phenomena, seismic activity has been the approach most often investigated. Particularly, foreshocks seem to offer the most potential. However, foreshocks are found to precede only a small fraction of major earthquakes and provide precursor parameters with too many kinds of diversity.

We need to find another seismic or similar phenomenon in the nucleation period with characteristics expected for foreshocks, i.e., a stable rate of occurrence and extremely large anomalies immediately before major earthquakes [1,2]. Here we make a special seismic catalog of high frequency tremors deduced anew from continuous seismic data of just before major earthquakes using the extensive network, High-net of Japan. Analyses of catalog of three major and one little bit smaller earthquakes show that there are three successive precursory phenomena, first at some six weeks, second at some four weeks, and finally immediately before the earthquake.

These results can provide evidence to predict major earthquakes without high rate of diversity among
threshold parameters; i.e., the selected threshold values for distinguishing precursor candidates are quite stable. Each precursory activity provides the three items of prediction, namely, occurrence time, epicenter and magnitude, with sufficient accuracy for practical disaster prevention efforts. The positive results will contribute to developing practical prediction methods to be used for the mitigation of serious earthquake disasters.

The proposed system is now in the level of POC, and expected to start in Japan without large difficulties because of sufficient level of observation network and storage of past data of some twenty years.

Open Access Original Research Article

Analysis of Radiological Hazard Indices from Mining Sites in Adamawa State, Nigeria

Samson Dauda Yusuf, Soja Reuben Joseph, Ibrahim Umar

Asian Journal of Physical and Chemical Sciences, Page 1-14
DOI: 10.9734/ajopacs/2022/v10i3181

Aims: To analyse the radiological hazard indices from mining sites in Adamawa State, Nigeria.

Study Design: Experimental study design using Gamma ray spectroscopy with a well calibrated Sodium Iodide (NaI) detector.

Place and Duration of Study: Adamawa State, Nigeria and Department of Physics, Nasarawa State University Keffi, Nigeria, and Centre for Energy Research and Training (CERT) Laboratory, Ahmadu Bello University Zaria, Nigeria between November 2019 and August 2020.

Methodology: Fifteen composite samples of soil from four mining sites collected using the systematic sampling techniques were analysed for activity concentrations of Ra-226, Th-232 and K-40 and Gamma Absorbed Dose Rate, Radium Equivalent Activity, External Hazard Index, Annual Effective Dose Rate and Excessive Life Cancer Risk were calculated.

Results: Mean activity concentrations Ra-226 (107.60Bq/kg), Th-232 (84.89Bq/kg), and K-40 (475.34Bq/kg) were all above the world average values 35Bq/kg, 30Bq/kg and 400Bq/kg recommended by UNSCEAR. Mean Gamma Absorbed Dose Rate, Radium Equivalent Activity, Annual Effective Dose Rate, External Hazard Index, and Excessive Life Cancer Risk were 120.31nGy/h, 265.469Bq/kg, 0.148mSv/y, 0.401, and 0.369 respectively, against recommended values 59nGy/h, 370Bq/kg, 1mSv/y, 0.45, and 0.29 according to UNSCER, NEA-OECD and ICRP.

Conclusion: High values of Activity Concentrations, Gamma Absorbed Dose, and Excessive Life Cancer Risk poses significant threat to the host community, especially around the 3 mining sites SA, SB and SC.

Therefore, safety distance from mining areas is recommended by the competent Authority responsible for radiation protection matters in Nigeria. General awareness to enlighten the public about the possible dangers of undue radiation exposure and the risk of residing close to mining vicinity is required, for adequate protection of the host community.

Open Access Original Research Article

Quality of Service Reliability: A Study of Received Signal Quality in GSM Networks

Joel Iloke, Ukoette Jeremiah Ekah, Enobong Joseph Oduobuk, Igwe Ewona, Emmanuel Obi

Asian Journal of Physical and Chemical Sciences, Page 25-34
DOI: 10.9734/ajopacs/2022/v10i3183

Every radio frequency (RF) design, after its implantation, should be regularly evaluated. The kernel of this article is to evaluate the performance of four GSM networks, taking its received signal quality (RxQual) into consideration. A total of 10501, 10140, 10415 and 10690 RxQual measurements were obtained for MTN, 9mobile, Airtel and Globacom network. These generated data were subjected to statistical analysis in the form of bar charts, quality plots and calculations of measures of central tendency and dispersion. Result shows that 78.43%, 92.18%, 90.68% and 86.93% of the drive test route for MTN, 9mobile, Airtel and Globacom network had good signal quality and met with the Nigerian telecommunication regulatory benchmark of at least 4dB for RxQual. It is therefore deduced that in terms of RxQual, 9mobile was the best GSM network, followed by Airtel network, Globacom network and then MTN network. The result provided in this article will help mobile network operators to improve signal quality, ensure improved network coverage and increase network capacity in the future.

Open Access Original Research Article

Status of Contamination of the Jawfish (Chrysichthys nigrodigitatus, (Lapécède, (1803)) by Organophosphorus Residues in the Hydroelectric Dams of Faé, Kossou and Taabo (Ivory Coast)

Koukougnon Kouho Lydie, Ossehin Ambroise, Acho Yapi Fulgence, Kone Mamadou, Traore Karim Sory

Asian Journal of Physical and Chemical Sciences, Page 35-44
DOI: 10.9734/ajopacs/2022/v10i3184

The present study aims at determining the level of contamination of the jawfish (Chrysichthys nigrodigitatus) by organophosphate residues in the hydroelectric dams of Faé, Kossou and Taabo. Ninety (90) fish were collected from these three dams during eight sampling campaigns. Composite samples were formed, each for two fish. A total of forty-five (45) composite samples were formed. The detection of pesticide residues in the fish samples was determined by gas chromatography-mass spectrometer (GC/MS). The results show that the average total organophosphate residue load at the three dams is 0.184 mg/kg. The Faé hydroelectric scheme had the highest total load of 0.266 mg/kg in fish samples, compared to 0.197 mg/kg for Taabo and 0.089 mg/kg for the Kossou hydroelectric dam. The relatively high average total concentration is observed for parathion-methyl with a value of 0.130 ± 0.023 mg/kg. Chlorfenvinphos, with a total average concentration of 0.046 ± 0.007 mg/kg was the only molecule present in all the fish samples analyzed in the three hydroelectric dams. In addition, most of the molecules detected in the fish samples had concentrations that exceeded the Maximum Residue Limits (MRLs) for pesticides, whose values range from 0.01 to 0.05 mg/kg.

Open Access Original Research Article

Measurement of Radioactivity Concentration in Pegmatite Rock Samples and Dose Assessment from Wamba in North Central Nigeria

Taiwo Bukola Fasiku, Musbau Kewulere Fasasi, Adebimpe Amos Amosun

Asian Journal of Physical and Chemical Sciences, Page 45-53
DOI: 10.9734/ajopacs/2022/v10i3185

Aims: To evaluate the radiological impact parameters on mine workers.

Study Design: The research work was carried out by using a gamma–ray spectrometer with a NaI (TI) detector.

Place and Duration of Study: Centre for Energy and Research Development (CERD), Obafemi Awolowo University, Ile- Ife, Osun State, Nigeria between September 2016 and June 2017.

Methodology: The activity concentrations of 226Ra, 232Th, and 40K were determined in ten samples which were used to evaluate the absorbed dose rate, radium equivalent activity, external and internal hazard indices, representative level index, and annual effective dose equivalent.

Results: The average activity concentrations of 226Ra (24068.11, 232Th (387.72 , 40K (9509.24) and absorbed dose rate (11720.77) were higher than their respective recommended world mean values of 35 , 45 , 420  and 59  by UNSCEAR. The mean values of radium equivalent activity, external hazard index (Hex), internal hazard index (Hin), representative level index, and annual effective dose equivalent of the area under study were determined as 25346.82, 68.52, 135.43, 357.95, and 14374.36 respectively. This study revealed that all the radiological parameters were higher than their respective recommended world average values.

Conclusion: With the high concentrations obtained in this study, it is therefore concluded that this may pose a serious health risk to the miners and the general public. It is therefore advised that necessary guidelines should be provided for the exploration of minerals in this mining site.