Complexity in Geophysical Time Series of Strain/Fracture at Laboratory and Large Dam Scales: Review

Chélidzé, T.; Matcharashvili, Teimuraz; Mepharidze, Ekaterine; Dovgal, Nadezhda

doi:10.3390/e25030467

Cited by 3 publications

(1 citation statement)

References 64 publications

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“…Because fractal behaviour, long memory, and complexity are interconnected concepts, examining one of them will usually result in the other. For example, examining a system's complexity will help to determine its long memory and vice versa [1,37,38]. All of these characteristics can show whether a system's past, present, and future are strongly connected.…”

Section: Fractal and Long Memorymentioning

confidence: 99%

Fractal Patterns in Groundwater Radon Disturbances Prior to the Great 7.9 Mw Wenchuan Earthquake, China

Alam,

Nikolopoulos,

Wang

2023

Geosciences

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This study reports a fractal analysis of one-year radon in groundwater disturbances from five stations in China amidst the catastrophic Wenchuan (Mw = 7.9) earthquake of 12 May 2008 (day 133). Five techniques are used (DFA, fractal dimensions with Higuchi, Katz, Sevcik methods, power-law analysis) in segmented portions glided throughout each signal. Noteworthy fractal areas are outlined in the KDS, GS, MSS data, whilst the portions were non-significant for PZHS and SPS. Up to day 133, critical epoch DFA-exponents are 1.5≤α<2.0, with several above 1.8. The fractal dimensions exhibit Katz’s D around 1.0–1.2, Higuchi’s D between 1.5 and 2.0, and Sevcik’s D between 1.0 and 1.5. Several power-law exponents are above 1.7, and numerous are above 2.0. All fractal results of the KDS-GS-MSS are further analysed using a novel computerised methodology that locates the exact out-of-threshold fractal areas and combines the outcomes of different methods per five, four, three, and two (maximum 13 combinations) versus nineteen Mw≥ 5.5 earthquakes of the greater area. Most coincidences using different techniques are before the great Wenchuan earthquake and after the earthquake. This is not only with one method but with 13 different methods. Other interpretations are also discussed.

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Section: Fractal and Long Memorymentioning

confidence: 99%

Fractal Patterns in Groundwater Radon Disturbances Prior to the Great 7.9 Mw Wenchuan Earthquake, China

Alam,

Nikolopoulos,

Wang

2023

Geosciences

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Fractal Patterns in Groundwater Radon Disturbances Prior to the Great <em>M<sub>w</sub></em>=7.9 Wenchuan Earthquake, China

Alam¹,

Nikolopoulos²,

Wang³

2023

Preprint

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This study reports fractal analysis of one-year radon in groundwater disturbances from five stations in China amid the catastrophic Wenchuan (Mw=7.9) earthquake of May 12, 2008 (day 133). Five techniques are used (DFA, fractal dimensions with Higuchi, Katz, Sevcik methods, power-law analysis) in segmented portions glided throughout each signal. Noteworthy fractal areas are outlined in the KDS, GS, MSS station data, while the portions were non-significant for PZHS and SPS. Up to day 133 critical epoch DFA-exponents have 1.5<=a<2.0 with several above 1.8. Fractal dimensions exhibit Katz’s D around 1.0-1.2, Higuchi’s D between 1.5-2.0 and Sevcik’s D between 1.0-1.5. Several power-law exponents are above 1.7 and numerous above 2.0. All fractal results of KDS-GS-MSS stations are further analysed using a novel computerised methodology which locates the exact out-of-threshold fractal areas and combines the outcomes of different methods per five, four, three, and two (maximum 13 combinations) versus nineteen Mw<=5.5 earthquakes of the area. Most different-technique coincidences are before the great Wenchuan earthquake and its post-earthquakes. This is not only with one method, but with 13 different methods. Other interpretations are also discussed.

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Fractal Features in kHz Electromagnetic Observations Preceding Near-Field Earthquakes in Ilia, Greece

Nikolopoulos,

Petraki,

Rafique

et al. 2023

Geosciences

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This paper reports kHz EM observations recorded by the Kardamas station in Ilia, Greece a few days before four near-field earthquakes occurred within a 24 km radius, with epicentral depths below 29 km. This work investigated the fractal features hidden in the EM observations via power-law analysis. All EM signals exhibited characteristic fractal epochs with organisation in space and time. A significant number of accurate fractal segments were delineated in the majority of the EM observations. A significant number of fractal areas corresponded to predictable Class I fBm category with 1 ≤ b ≤ 3 (0 ≤ H ≤ 1). Numerous persistent key-periods are reported with 2 < b ≤ 3 (0.5 ≤ H ≤ 1) which are deemed as signs of impeding earthquakes according to the literature. Numerous segments were found with strong persistent b-values in the range (2.3 ≤ b ≤ 3) (0.65 ≤ H ≤ 1) and b-values corresponding to switching between antipersistency and persistency with (1.7 ≤ b < 2.3) (0.35 ≤ H < 0.65). These are deemed as the most significant precursory signs. Interpretations are given via the asperity model.

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Complexity in Geophysical Time Series of Strain/Fracture at Laboratory and Large Dam Scales: Review

Cited by 3 publications

References 64 publications

Fractal Patterns in Groundwater Radon Disturbances Prior to the Great 7.9 Mw Wenchuan Earthquake, China

Fractal Patterns in Groundwater Radon Disturbances Prior to the Great 7.9 Mw Wenchuan Earthquake, China

Fractal Patterns in Groundwater Radon Disturbances Prior to the Great <em>M<sub>w</sub></em>=7.9 Wenchuan Earthquake, China

Fractal Features in kHz Electromagnetic Observations Preceding Near-Field Earthquakes in Ilia, Greece

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