Anomalous soil radon fluctuations – signal of earthquakes in Nepal and eastern India regions

Deb, Argha; Gazi, Mahasin; Barman, Chiranjib

doi:10.1007/s12040-016-0757-z

Cited by 32 publications

(9 citation statements)

References 47 publications

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“…In the literature, anomalies are observed also for earthquakes as small as M ≈ 3, but the most common observations are related to earthquake with M > 4.5. Anomalies could anticipate, or follow, a local earthquake of hours, days, or even months and may vary in term of rate, absolute amplitude, and temporal response (Chowdhury et al., 2017; Deb et al., 2016; Friedmann, 2012; Piersanti et al., 2016; Papachristodoulou et al., 2019; Tarakçı et al., 2014; Weinlich et al., 2006; Zafrir et al., 2016).…”

Section: Discussionmentioning

confidence: 99%

Long‐Term Monitoring and Characterization of Soil Radon Emission in a Seismically Active Area

D’Alessandro

Scudero

Siino

et al. 2020

Geochem Geophys Geosyst

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Radon (222Rn) is a radioactive gas, which originates everywhere in rocks of Earth's crust through a process of natural decay of other radioactive elements. The monitoring of soil radon can be useful to address a multitude of geological and environmental issues. However, some difficulties arise when trying to use radon as earthquake precursor because the earthquake‐related anomaly cannot be easily and univocally discriminated from other anomalies of different origin. To explore the relationship between soil radon emission and seismicity, a local network is operating in southeastern Sicily (Italy). Its peculiarities are the uniform geological condition of the monitoring sites and the long data record with simultaneous measures of radon and the main climate variables. In this paper, we applied continuous wavelet transformation to a ≈ 3.5 years long soil radon time series to detect periodic variations. Results indicate the occurrence of cycles at annual, semiannual, and monthly periodicity, which are ascribable to the effects of the climatic‐environmental parameters. The periodic components have been modeled and the signal conveniently filtered. We show as the characterization of the long‐term behavior of radon signals is essential to recognize anomalies in radon emission, which can be related to geological/environmental phenomena. The methodology proposed in this work provides a reliable characterization of the radon time series and can be applied at various spatial/temporal scales, depending on the scientific objectives to be achieved. This approach can also represent the base for further analysis like the investigation of the modulation between the periodic components and short‐term forecasts.

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Section: Discussionmentioning

confidence: 99%

Long‐Term Monitoring and Characterization of Soil Radon Emission in a Seismically Active Area

D’Alessandro

Scudero

Siino

et al. 2020

Geochem Geophys Geosyst

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“…Pengamatan gas radon di daerah aktif tektonik di sebelah barat Turki menunjukkan adanya korelasi linier antara tingkat emisi radon dan aktivitas seismik di wilayah yang diteliti (Murat drr., 2011). Di Nepal, data monitoring gas radon selama empat bulan menunjukkan adanya anomali sebelum gempa 25 April 2015 dengan magnitudo M 7,8 (Deb, Gazi, dan Barman, 2016).…”

Section: Pendahuluanunclassified

Variasi Gas Radon dan Aktivitas Kegempaan di Sekitar Patahan Opak

Sunardi¹

2018

J. lingkung.

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Monitoring gas radon di dalam tanah telah dilakukan secara kontinyu selama dua tahun terakhir di sekitar patahan Opak Yogyakarta sebagai salah satu upaya mitigasi bencana gempa. Penelitian ini bertujuan menganalisis variasi radon dan aktivitas kegempaan yang terjadi di sekitar patahan Opak serta mengeksplorasi munculnya prekursor untuk gempa lokal. Monitoring data radon dilakukan di dua lokasi yaitu di daerah Pundong dan Piyungan, sedangkan aktivitas gempa di sekitar patahan Opak diperoleh dari data repositori gempabumi BMKG. Eksplorasi anomali radon untuk melihat adanya prekursor gempa dilakukan dengan menerapkan metode korelasi. Anomali radon ditetapkan apabila rasio simpangan koefisien korelasi (Sk) dengan deviasi standar (Ds) lebih kecil dari -1. Hasil penelitian menunjukkan peningkatan emisi gas radon berkorelasi dengan kenaikan frekuensi kejadian gempa. Penerapan metode korelasi memperlihatkan beberapa anomali radon yang dapat diklasifikasikan sebagai prekursor gempa di sekitar patahan Opak. Penelitian lebih lanjut diperlukan untuk melihat konsistensi hasil monitoring anomali radon dengan kejadian gempa di sekitar patahan Opak.

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“…The 2015 earthquake sequence in Nepal has been studied with different methods for pre-earthquake anomalies. Several authors show precursory phenomena by using different satellite and ground observations: a/Satellite thermal anomalies (Ouzounov et al, 2015;Prakash et al, 2015;Shan et al, 2016); b/Microwave Brightness Temperature Anomalies (Qi et al, 2020); c/Radon anomalies (Deb et al, 2016); d/Ionospheric anomalies (Ouzounov et al, 2015;Maurya et al, 2016;Oikonomou et al, 2016;Li et al, 2016;De Santis et al, 2017); e/Gravity anomalies (Chen et al, 2015). We used a multi-parameter approach to search for pre-earthquake signals associated with the series of strong earthquakes in Nepal during April-May 2015.…”

Section: Introductionmentioning

confidence: 99%

Transient Effects in Atmosphere and Ionosphere Preceding the 2015 M7.8 and M7.3 Gorkha–Nepal Earthquakes

Ouzounov¹,

Пулинец²,

Davidenko³

et al. 2021

Front. Earth Sci.

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We analyze retrospectively/prospectively the transient variations of six different physical parameters in the atmosphere/ionosphere during the M7.8 and M7.3 earthquakes in Nepal, namely: 1) outgoing longwave radiation (OLR) at the top of the atmosphere (TOA); 2) GPS/TEC; 3) the very-low-frequency (VLF/LF) signals at the receiving stations in Bishkek (Kyrgyzstan) and Varanasi (India); 4) Radon observations; 5) Atmospheric chemical potential from assimilation models; and; 6) Air Temperature from NOAA ground stations. We found that in mid-March 2015, there was a rapid increase in the radiation from the atmosphere observed by satellites. This anomaly was located close to the future M7.8 epicenter and reached a maximum on April 21–22. The GPS/TEC data analysis indicated an increase and variation in electron density, reaching a maximum value during April 22–24. A strong negative TEC anomaly in the crest of EIA (Equatorial Ionospheric Anomaly) occurred on April 21, and a strong positive anomaly was recorded on April 24, 2015. The behavior of VLF-LF waves along NWC-Bishkek and JJY-Varanasi paths has shown abnormal behavior during April 21–23, several days before the first, stronger earthquake. Our continuous satellite OLR analysis revealed this new strong anomaly on May 3, which was why we anticipated another major event in the area. On May 12, 2015, an M7.3 earthquake occurred. Our results show coherence between the appearance of these pre-earthquake transient’s effects in the atmosphere and ionosphere (with a short time-lag, from hours up to a few days) and the occurrence of the 2015 M7.8 and M7.3 events. The spatial characteristics of the pre-earthquake anomalies were associated with a large area but inside the preparation region estimated by Dobrovolsky-Bowman. The pre-earthquake nature of the signals in the atmosphere and ionosphere was revealed by simultaneous analysis of satellite, GPS/TEC, and VLF/LF and suggest that they follow a general temporal-spatial evolution pattern that has been seen in other large earthquakes worldwide.

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Anomalous soil radon fluctuations – signal of earthquakes in Nepal and eastern India regions

Cited by 32 publications

References 47 publications

Long‐Term Monitoring and Characterization of Soil Radon Emission in a Seismically Active Area

Long‐Term Monitoring and Characterization of Soil Radon Emission in a Seismically Active Area

Variasi Gas Radon dan Aktivitas Kegempaan di Sekitar Patahan Opak

Transient Effects in Atmosphere and Ionosphere Preceding the 2015 M7.8 and M7.3 Gorkha–Nepal Earthquakes

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