Assessment of signal processing methods for geomagnetic precursor of the 2012 M6.9 Visayas, Philippines earthquake

Yusof, Khairul Adib; Hamid, Nurul Shazana Abdul; Abdullah, Mardina; Ahadi, Suaidi; Yoshikawa, Akimasa

doi:10.1007/s11600-019-00319-w

Cited by 26 publications

(16 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In theory, the amplitude of P Z/G would increase anomalously due to the direct lithospheric emission a few weeks to several days before an earthquake. This observation was reported by prior studies [14][15][16].…”

Section: Introductionsupporting

confidence: 86%

“…Similarly, nighttime period, ∆T, also differed across studies; thus, five different periods (∆T = 22-02, 23-03, 00-04, 01-05 and 02-06 LT) were examined for each earthquake to identify the least geomagnetically disturbed period at which precursors appeared. An anomaly is identified when the P Z/G value of a particular day exceeds the mean plus two times the standard deviation (µ + 2σ) of the entire period of observation [15]. If the anomaly appeared during an undisturbed period, then the anomaly was assumed to be a possible precursor.…”

Section: Precusor Detectionmentioning

confidence: 99%

“…Moreover, seismo-EM emission is difficult to be distinguished from the much greater background natural EM field. The polarization ratio analysis (PRA) method was used in many studies where the ratio of vertical (Z) to total horizontal (G) geomagnetic field components is used as a potential precursory parameter, referred to as P Z/G parameter, e.g., [14,15]. The premise of the method is that the seismo-EM emission is assumed to be prevalent in the Z component in contrast to the magnetospheric-originating signal which dominates the G component [16].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Correlations between Earthquake Properties and Characteristics of Possible ULF Geomagnetic Precursor over Multiple Earthquakes

et al. 2021

Self Cite

View full text Add to dashboard Cite

In this study, we improved and adapted existing signal processing methods on vast geomagnetic field data to investigate the correlations between various earthquake properties and characteristics of possible geomagnetic precursors. The data from 10 magnetometer stations were utilized to detect precursory ultra-low frequency emission and estimate the source direction for 34 earthquakes occurring between the year 2007–2016 in Southeast Asia, East Asia, and South America regions. As a result, possible precursors of 20 earthquakes were identified (58.82% detection rate). Weak correlations were obtained when all precursors were considered. However, statistically significant and strong linear correlations (r ≥ 0.60, p < 0.05) were found when the precursors from two closely located stations in Japan (Onagawa (ONW) and Tohno (TNO)) were exclusively investigated. For these stations, it was found that the lead time of the precursor is strongly (or very strongly) correlated with the earthquake magnitude, the local seismicity index, and the hypocentral depth. In addition, the error percentage of the estimated direction showed a strong correlation with the hypocentral depth. It is concluded that, when the study area is restricted to a specific location, the earthquake properties are more likely to have correlations with several characteristics of the possible precursors.

show abstract

Section: Introductionsupporting

confidence: 86%

Section: Precusor Detectionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Correlations between Earthquake Properties and Characteristics of Possible ULF Geomagnetic Precursor over Multiple Earthquakes

et al. 2021

Self Cite

View full text Add to dashboard Cite

show abstract

“…The method to study the earthquake is polarization ratio. The polarization ratio analysis method has successfully detected an anomaly preceding the main earthquake (Yusof et al, 2019). The H-component or Horizontal intensity is suitable to study the geomagnetic storm.…”

Section: Period Of Studymentioning

confidence: 99%

South Atlantic Anomalyduring ascending and maximum phase of solar cycle 24

Nasuddin

Abdullah

Hamid

2020

Preprint

Self Cite

View full text Add to dashboard Cite

Abstract. For this research, four regions have been studied which are the South Atlantic Anomaly (SAA) region, low latitude region, middle latitude region and high latitude region. The active period which is the period when the geomagnetic storm occur chosen to be analyzed is on 6 August 2011 and 12 April 2014 and the normal period, a period when no geomagnetic storm happen is on 24 July 2011 and 14 May 2014. Year 2011 is chosen to be analyze in order to study the SAA region during the ascending phase of the solar cycle 24 and in year 2014, where the occurrence of the maximum phase of solar cycle 24 occur. The research is carried since there is no clear characterization of the SAA during ascending as well as maximum phase based on power spectrum analysis method. The Earth's magnetic field component chosen to be analyzed is the horizontal intensity (H) due to its sensitiveness regarding geomagnetic activeness. From the research conducted, the result reveal SAA region has a tendency to be persistent during both period compare to other region during both phases. Other regions in the research experience a tendency to be persistent and antipersistent.

show abstract

“…However, the ULF emission that can be assigned as electromagnetic anomalies has sometimes been problematic because not only is the intensity very weak (around 1nT) but it is usually difficult to understand as well due to the intense natural background of the geomagnetic field [8]. To distinguish between the emission and the background, polarization analysis has been applied to separate the vertical component of the geomagnetic field from the horizontal component [9,10]. The Comparative Polarization signal for the H and Z components separates the ULF emission of solar wind, magnetosphere, ionosphere, or lithosphere and is derived from seismic origins [11].…”

Section: Introductionmentioning

confidence: 99%

Geomagnetic anomaly associated with Fukushima earthquake on February 13^th, 2021

et al. 2021

View full text Add to dashboard Cite

In this study, we performed research on electromagnetic anomalies related to earthquakes as early signs (precursors) that occurred in Fukushima, Japan on February 13th, 2021. The research focused on the utilization of geomagnetic field data which was derived from the Kakioka (KAK), Kanoya (KNY), and Memambetsu (MMB) observatories, particularly in the ultra-low frequency (ULF) to detect earthquake precursors. The method of electromagnetic data processing was conducted by applying a polarization ratio. In addition, we improved the methodology by splitting the ULF data (which ranged from 0.01-0.1 Hz) into 9 central frequencies and picking up the highest value from each central frequency to get the polarization ratio. The anomaly of magnetic polarization was identified 2-3 weeks before the mainshock in a narrowband frequency in the range of 0.04-0.05 Hz.

show abstract

Assessment of signal processing methods for geomagnetic precursor of the 2012 M6.9 Visayas, Philippines earthquake

Cited by 26 publications

References 25 publications

Correlations between Earthquake Properties and Characteristics of Possible ULF Geomagnetic Precursor over Multiple Earthquakes

Correlations between Earthquake Properties and Characteristics of Possible ULF Geomagnetic Precursor over Multiple Earthquakes

South Atlantic Anomalyduring ascending and maximum phase of solar cycle 24

Geomagnetic anomaly associated with Fukushima earthquake on February 13^th, 2021

Contact Info

Product

Resources

About

Assessment of signal processing methods for geomagnetic precursor of the 2012 M6.9 Visayas, Philippines earthquake

Cited by 26 publications

References 25 publications

Correlations between Earthquake Properties and Characteristics of Possible ULF Geomagnetic Precursor over Multiple Earthquakes

Correlations between Earthquake Properties and Characteristics of Possible ULF Geomagnetic Precursor over Multiple Earthquakes

South Atlantic Anomalyduring ascending and maximum phase of solar cycle 24

Geomagnetic anomaly associated with Fukushima earthquake on February 13th, 2021

Contact Info

Product

Resources

About

Geomagnetic anomaly associated with Fukushima earthquake on February 13^th, 2021