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About anomal changes in hydrogeoseismological parameters associated with the Baysun earthquake on May 12, 2022 in the groundwater of the “Shurchi” comprehensive forecasting station
Sho‘rchi kompleks prognostik stantsiyasi yerosti suvlarida 2022 yil 12 maydagi Boysun zilzilasi bilan bog‘liq bo‘lgan gidrogeoseysmologik parametrlarning anomal o‘zgarishlari haqida
- Institute of Seismology, Academy of Sciences of the Republic of Uzbekistan, Uzbekistan
Highlights
- Shurchi-5 well: drilled 1981, 190–200 m deep, in Neogene–Quaternary (N+Q) sandstone, siltstone and clay; sampled daily except Sunday.
- Earthquake: 12 May 2022, 15:27 local time, M 6.0, Boysun district, depth 15 km, 83 km from the station.
- Dissolved CO₂: 0.05–0.1% on average, 1.5–2.2% in the active period, a 4–5-fold rise lasting 2–2.5 months.
- pH: usually 7.6–7.9, falling to 7–7.3.
Keywords
- hydrogeoseismology
- groundwater
- carbon dioxide
- Surkhandarya
- Shurchi
- earthquake precursors
Summary
A. V. Rasulov, G. I. Khasanova, R. K. Umurzakov and B. R. Qayumov, of the Institute of Seismology of the Academy of Sciences of Uzbekistan, analyse changes in groundwater at the Shurchi station in Surkhandarya region linked to the earthquake of 12 May 2022. The Shurchi-5 well was drilled in 1981 and has been used for hydrogeoseismological observations since then. It is 190–200 m deep in Quaternary and Neogene (N+Q) sandstone, siltstone and clay. Water is sampled every day except Sunday; helium, hydrogen, nitrogen, oxygen, methane, carbon dioxide and other gases are measured by chromatograph, with a shortened chemical analysis in the laboratory and pH by ionometer.
The earthquake, of M 6.0, struck at 15:27 local time on 12 May 2022 in Boysun district, at a depth of 15 km and 83 km from the station. From July 2022 dissolved carbon dioxide in the groundwater rose: from an average of 0.05–0.1% of the sample to 1.5–2.2% in the active period, which lasted 2–2.5 months; over this time the carbon dioxide in the water increased 4–5 times. In their conclusions the authors place the start of the largest anomaly 2–2.5 months before the earthquake and its return to background over the same time after it.
The usual average pH of the groundwater, 7.6–7.9, fell to 7–7.3 in the period of seismic activity. Dissolved oxygen decreased before the activity, and bicarbonate also varied; the pH and oxygen graphs cover January 2021 to mid-2023. The authors regard these anomalies as a possible precursor of the earthquake.
How to cite
A. V. Rasulov, G. I. Khasanova, R. K. Umurzakov and B. R. Qayumov (2023). About anomal changes in hydrogeoseismological parameters associated with the Baysun earthquake on May 12, 2022 in the groundwater of the “Shurchi” comprehensive forecasting station. Seysmologiya muammolari (Problems of Seismology), vol. 5, No. 2, 2023, pp. 25–28. https://seismos.uz/uploads/pdf/journal/%D0%A1%D0%B5%D0%B9%D1%81%D0%BC%D0%BE%D0%BB%D0%BE%D0%B3%D0%B8%D1%8F%20%D0%BC%D1%83%D0%B0%D0%BC%D0%BC%D0%BE%D0%BB%D0%B0%D1%80%D0%B8%202023%20%E2%84%962.pdf