scholarly journals Occurrence of anomalies in soil radon volume activity before tectonic earthquakes

LITOSFERA ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 724-733
Author(s):  
I. A. Kozlova ◽  
S. V. Biryulin ◽  
A. K. Yurkov
Keyword(s):  
Research Area ◽  
Monitoring Station ◽  
Seismic Events ◽  
Time Interval ◽  
World Population ◽  
Marine Geology ◽  
Soil Radon ◽  
Marine Geology And Geophysics ◽  
Tectonic Earthquakes ◽  
Precursors Of Earthquakes

Research subject. Earthquakes are a global problem for the entire world population. Therefore, a search for ways to predict and prevent tectonic events is a highly relevant task. Despite the existence of controversial opinions on the possibility of predicting tectonic earthquakes, research in this direction continues. Among numerous possible precursors of earthquakes, anomalies in the volume radon activity (VRA) are the most physically justifed ones. The aim of this research was to compare the observed anomalies of soil radon with the recorded seismic events in order to fnd common patterns. The research area was the Kuril Islands. VRA monitoring was conducted at the South Kuril Geophysical Station of the Institute of Marine Geology and Geophysics of the Far Eastern Branch of the Russian Academy of Sciences.Methods and materials. Measurements were carried out in the advective mode: soil air from a depth of 70 cm was forcibly delivered to the detector using a pump. For a retrospective analysis, we took registered seismic events with a magnitude greater than 4 that occurred within a radius of 500 km from the monitoring station in Yuzhno-Kurilsk during 2011–2018. Statistical data were processed using Microsoft Excel, Statistica software. Results. A method for comparing radon anomalies and earthquakes was developed. Using the developed methodology, it was found that the geodynamic criterion of ≥2 (the ratio of earthquake magnitude to logarithm of distance from event epicenter to the monitoring station in km) can be used when comparing VRA anomalies with tectonic earthquakes. Out of the 166 considered tectonic earthquakes meeting the geodynamic criterion of ≥2.148, the events were preceded by VRA anomalies. The position of the earthquakes was determined relative to the extremum of previous anomalous radon values in the time interval. Eac  of the considered earthquakes meeting the geodynamic criterion ≥2, which had been preceded by a radon anomaly, occurred either after its extremum or coincided with it in time. Conclusions. The manifestation of tectonic earthquakes in VRA anomalies after passing the extremum can be considered as a short-term prognostic criterion and be used for distinguishing between “near” and “far” events.

Early Cambrian Seismic Events and Their Tectonic Significance in Western Zhejiang

2012 ◽  
Vol 524-527 ◽  
pp. 42-48
Author(s):  
Fu Sheng Guo ◽  
Zhao Bin Yan ◽  
Liu Qin Chen
Keyword(s):  
Seismic Event ◽  
Regional Distribution ◽  
Sedimentary Rocks ◽  
Seismic Events ◽  
Time Interval ◽  
Early Cambrian ◽  
Distribution Characteristics ◽  
Early Paleozoic ◽  
Tectonic Events ◽  
Tectonic Significance

The two early Cambrian seismic events could be found from sedimentary rocks at Peilingjiao section of Kaihua County, Baishi and Fangcun sections of Changshan County in western Zhejiang, except for Jiangshan area. The seismic event at Baishi outcrop can be correlated to the second seismic event at Peilingjiao section. Taking Fangcun as epicenter of the second seismic event, the magnitude of paleoseism in western Zhejiang is about 7~7.6. According to investigation on regional distribution of seismic events, the two seismic activities should be regulated by large Kaihua-Chun’an fault, but unrelated with Jiangshan-Shaoxing fault or Changshan-Xiaoshan fault. However, the formation time of Kaihua-Chun’an fault has not yet been determinate. Based on controlling on Silurian, the possible formation age was inferred to early Paleozoic. The distribution characteristics of seismites indicate that the Kaihua-Chun’an fault was already being active during early Cambrian and seismic activities may be response to Sinian tectonic events in western Zhejiang. By the way of analysis on paleoseismic rhythm, the time interval of the two seismic events in western Zhejiang is less than 5.0 Ma, which may be the result of early frequent activities of Kaihua-Chun’an fault.

scholarly journals Estimation of relative source locations from seismic amplitude: application to earthquakes and tremors at Meakandake volcano, eastern Hokkaido, Japan

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Masashi Ogiso ◽  
Kiyoshi Yomogida
Keyword(s):  
Amplitude Ratio ◽  
Linear Equations ◽  
Site Amplification ◽  
New Method ◽  
Seismic Events ◽  
Arrival Times ◽  
Event Location ◽  
Tectonic Earthquakes ◽  
The Difference ◽  
Seismic Amplitudes

AbstractAlthough seismic amplitudes can be used to estimate event locations for volcanic tremors and other seismic events with unclear phase arrival times, the precision of such estimates is strongly affected by site amplification factors. Therefore, reduction of the influence of site amplification will allow more precise estimation of event locations by this method. Here, we propose a new method to estimate relative event locations using seismic amplitudes. We use the amplitude ratio between two seismic events at a given station to cancel out the effect of the site amplification factor at that station. By assuming that the difference between the hypocentral distances of these events is much smaller than their hypocentral distances themselves, we derive a system of linear equations for the differences in relative event locations. This formulation is similar to that of a master event location method that uses differences in phase arrival times. We applied our new method to earthquakes and tremors at Meakandake volcano, eastern Hokkaido, Japan. Comparison of the hypocentral distributions of volcano-tectonic earthquakes obtained thereby with those obtained from phase arrival times confirmed the validity of our new method. Moreover, our method clearly identified source migration among three source regions in the tremor on 16 November 2008, consistent with previous interpretations of other geophysical observations in our study area. Our method will thus be useful for detailed analyses of seismic events whose onset times are ambiguous.

Use of U.S. Census Bureau Data to Expose Students to Dynamic Population Growth

2017 ◽  
Vol 79 (7) ◽  
pp. 572-577
Author(s):  
Evan Lampert
Keyword(s):  
Population Size ◽  
Human Population ◽  
Census Bureau ◽  
Rate Of Change ◽  
Time Interval ◽  
World Population ◽  
Quantitative Literacy ◽  
Online Databases ◽  
Dynamic Population ◽  
The U.S

Global human population size and understanding how it has changed and will change in the future are important concepts for students. Here I describe exercises that use online databases provided by the U.S. Census Bureau to show students how both population size and the rate of change vary over time. In the first exercise, the U.S. population clock is used to calculate daily birth, death, and migrant and death rates, and how the world population clock is used to calculate the rate of change. These rates can be used to predict what the population size would be if the rates remained unchanged for a predetermined time interval. In the second exercise, historical data are used to determine the years with the most change in U.S. and world population size, then calculate how much larger the current population would be if those historical rates of change remained constant. These exercises have improved quantitative literacy while showing students current and historical trends in human population.

scholarly journals Anomaly detection on in-home activities data based on time interval

2019 ◽  
Vol 15 (2) ◽  
pp. 778
Author(s):  
Soon-Chang Poh ◽  
Yi-Fei Tan ◽  
Soon-Nyean Cheong ◽  
Chee-Pun Ooi ◽  
Wooi-Haw Tan
Keyword(s):  
Anomaly Detection ◽  
Past Research ◽  
The Elderly ◽  
Behavioral Changes ◽  
Time Interval ◽  
World Population ◽  
Continuous Growth ◽  
Detection Model ◽  
Health Decline ◽  
Testing Data

<span>The world population of the elderly is expected to have a continuous growth and the number of elderly living in solitude is also expected to increase in the coming years. As our health decline with age, early detection of possible deterioration in health becomes important. Behavioral changes in in-home activities can be used as an indicator of health decline. For example, changes in routine of in-home activities. Past research mainly focused on detecting anomalies in routine of each type of in-home activities individually. In this paper, an anomaly detection model to detect changes in routine of in-home activities collectively for a day is proposed. The experiment was evaluated with an existing public dataset. The experimental results demonstrated that the anomaly detection model performed well on unseen testing data with an accuracy of 94.44%.</span>

scholarly journals Statistical moments of power spectrum: a fast tool for the classification of seismic events recorded on volcanoes

2020 ◽  
Vol 52 ◽  
pp. 67-74
Author(s):  
Danilo Galluzzo ◽  
Lucia Nardone ◽  
Mario La Rocca ◽  
Antonietta M. Esposito ◽  
Roberto Manzo ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
Low Frequency ◽  
Signal Amplitude ◽  
Low Noise ◽  
Seismic Events ◽  
Spectral Moments ◽  
Spectral Parameters ◽  
Seismic Stations ◽  
Event Classification ◽  
Tectonic Earthquakes

Abstract. Spectral analysis has been applied to almost thousand seismic events recorded at Vesuvius volcano (Naples, southern Italy) in 2018 with the aim to test a new tool for a fast event classification. We computed two spectral parameters, central frequency and shape factor, from the spectral moments of order 0, 1, and 2, for each event at seven seismic stations taking the mean among the three components of ground motion. The analyzed events consist of volcano-tectonic earthquakes, low frequency events and unclassified events (landslides, rockfall, thunders, quarry blasts, etc.). Most of them are of low magnitude, and/or low maximum signal amplitude, therefore the signal to noise ratio is very different between the low noise summit stations and the higher noise stations installed at low elevation around the volcano. The results of our analysis show that volcano-tectonic earthquakes and low frequency events are easily distinguishable through the spectral moments values, particularly at seismic stations closer to the epicenter. On the contrary, unclassified events show the spectral parameters values distributed in a broad range which overlap both the volcano-tectonic earthquakes and the low frequency events. Since the computation of spectral parameters is extremely easy and fast for a detected event, it may become an effective tool for event classification in observatory practice.

scholarly journals PHOSPHORITES OF THE BRAZILIAN CONTINENTAL MARGIN, SOUTHWESTERN ATLANTIC OCEAN

2014 ◽  
Vol 32 (3) ◽  
pp. 539 ◽  
Author(s):  
José Gustavo Natorf de Abreu ◽  
Iran Carlos Stalliviere Corrêa ◽  
Norberto Olmiro Horn Filho ◽  
Lauro Júlio Calliari
Keyword(s):  
Continental Margin ◽  
Rio Grande ◽  
Marine Geology ◽  
Southwestern Atlantic ◽  
X Ray Diffraction ◽  
Mineral Potential ◽  
Brazilian Government ◽  
Southwestern Atlantic Ocean ◽  
Marine Geology And Geophysics ◽  
Phosphate Deposits

ABSTRACT. The existence of phosphate deposits in the Brazilian continental margin is known since the 1970’s and 1980’s after the Global Recognition of the Brazilian Continental Margin Program – REMAC Project (Programa de Reconhecimento Global da Margem Continental Brasileira – Projeto REMAC) a joint program to explorethe Brazilian continental margin. Phosphate deposits were collected on the seamounts offshore the northeastern Brazilian margin. In the early 2000’s, phosphate sampleswere taken incidentally by demersal fishing fleet in the southern Brazilian continental margin which contributed to the knowledge of these deposits in the southwestern Atlantic. This paper describes the mineralogy of the samples with scanning electron microscopy and X-ray diffraction. The new phosphate deposits in the Brazilian continental margin suggests a much wider phosphate distribution than imagined in the REMAC publications, thus representing a contribution to the effort of the Brazilian Government, through the Ministry of Mines and Energy, the Geological Survey of Brazil (CPRM), the Inter-ministerial Commission for the Resources of the Sea andthe Marine Geology and Geophysics Program who together undertake a Program to the Evaluation of the Mineral Potential of the Brazilian Legal Continental Shelf(REMPLAC), whose goal is to conduct a further investigation of the mineral potential of the Brazilian Territorial Sea and Exclusive Economic Zone (EEZ).Keywords: marine mineral resource, phosphate deposits, Rio Grande Terrace. RESUMO. A existência de depósitos fosfáticos na margem continental brasileira é conhecida desde as décadas de 1970 e 1980, graças ao Projeto de Reconhecimento Global da Margem Continental Brasileira (REMAC) quando fosforitas foram recolhidas sobre os montes submarinos da região Nordeste. No início dos anos 2000, amostras foram obtidas incidentalmente pela frota pesqueira demersal na margem continental sul brasileira, as quais foram incorporadas como novas ocorrências, contribuindo para o conhecimento destes depósitos no Atlântico sul ocidental. Este trabalho descreve a mineralogia deste material amostrado a partir de análises realizadas com microscópio eletrônico de varredura e difratometria de raios X. A localização das novas ocorrências de depósitos fosfáticos na margem continental brasileira sugere uma distribuição bem mais ampla desses recursos minerais marinhos do que se imaginava até as publicações do REMAC, representando, portanto, uma contribuição ao esforço do governo brasileiro, através do Ministério de Minas e Energia, do Serviço Geológico do Brasil, da Comissão Interministerial para os Recursos do Mar e do Programa de Geologia e Geofísica Marinha que, juntos, empreendemo Programa de Avaliação da Potencialidade Mineral da Plataforma Continental Jurídica Brasileira (REMPLAC), cujameta é realizar estudos mais aprofundados sobre a potencialidade mineral do Mar Territorial Brasileiro e da Zona Econômica Exclusiva (ZEE).Palavras-chave: recurso mineral marinho, depósitos fosfáticos, Terraço do Rio Grande.

Sign in / Sign up

Export Citation Format

Share Document