Fractal Features in kHz Electromagnetic Observations Preceding Near-Field Earthquakes in Ilia, Greece
This paper reports <i>kHz</i> 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 p...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2023-12-01
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| Series: | Geosciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2076-3263/13/12/387 |
| Summary: | This paper reports <i>kHz</i> 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 ≤ <i>b</i> ≤ 3 (0 ≤ <i>H</i> ≤ 1). Numerous persistent key-periods are reported with 2 < <i>b</i> ≤ 3 (0.5 ≤ <i>H</i> ≤ 1) which are deemed as signs of impeding earthquakes according to the literature. Numerous segments were found with strong persistent <i>b</i>-values in the range (2.3 ≤ <i>b</i> ≤ 3) (0.65 ≤ <i>H</i> ≤ 1) and <i>b</i>-values corresponding to switching between antipersistency and persistency with (1.7 ≤ <i>b</i> < 2.3) (0.35 ≤ <i>H</i> < 0.65). These are deemed as the most significant precursory signs. Interpretations are given via the asperity model. |
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| ISSN: | 2076-3263 |