The possibility of estimating the coseismic deformation from water level observations in wells

Копылова, Г. Н.; Steblov, G. M.; Болдина, С. В.; Sdelnikova, I. A.

doi:10.1134/s1069351310010040

Cited by 9 publications

(21 citation statements)

References 7 publications

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“…The passage of surface seismic waves from the strongest earthquakes with М w of about 8-9 at epicentral distances of hundreds to thousands of kilometers due to water level variations (hydroseisms) with amplitudes of up to 9 cm and durations of several hours to one day. More detailed data on the well structure, elastic and filtering properties of water-saturated rocks, regularities of the hydrogeodynamic regime, and earthquake effects in water level changes are presented in our earlier publications (Kopylova, 2006a;Kopylova and Boldina, 2006;Kopylova et al, 2010Kopylova et al, , 2016Kopylova, 2016, 2017) and in publications by other authors.…”

Section: Technical Conditions Of Observations and Initial Datamentioning

confidence: 99%

“…In seismoactive regions, water level measurements are used to study how seismicity affects water level variations through the effects of seismic waves, coseismic deformation of water-saturated rocks, and hydrogeodynamic earthquake precursors (Roeloffs, 1988;Roeloffs et al, 1989;Igarashi and Wakita, 1991;Kissin, 1993Kissin, , 2009Kopylova, 2006b;Kopylova et al, 2010;Wang and Manga, 2010). Recent studies in Kamchatka have shown that application of traditional processing methods to water level measurement data (Kopylova, 2001(Kopylova, , 2006a, aimed at distinguishing lowfrequency trends in water level variations, can aid in detecting hydrogeodynamic precursors (HPs) before strong earthquakes.…”

Section: Introductionmentioning

confidence: 99%

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Statistical Analysis of Precision Water Level Data from Observations in a Seismoactive Region: Case Study of the YuZ-5 Well, Kamchatka

2019

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A new method is presented for statistical analysis of long-term time series of water level observations aimed at distinguishing short-term disturbances; observation data from the YuZ-5 well, located in the Petropavlovsk Geodynamic Test Area, eastern Kamchatka, are considered. These data (from July 27, 2012, to February 1, 2018) are remarkable for their degree of detail: the sampling rate of the water level and atmospheric pressure measurements was 5 min and the sensitivity (accuracy) was ±0.1 cm for water level recording and ±0.1 hPa for atmospheric pressure. Also, five strong earthquakes with M w = 6.5-8.3 occurred at epicentral distances of d e = 80-700 km during the observation period. A thorough analysis of the hydrodynamic regime of the observation well over a long period and the high quality of observation data, together with the data on strong seismic events, allow us to consider the possibility of using formalized statistical methods of water level data processing for diagnostics of anomalous conditions. As a result of factor and cluster analysis applied to the sequence of multidimensional vectors of the statistical properties of water level time series in successive one-day-long time windows, after adaptive compensation for atmospheric pressure, four different statistically significant states of time series, replacing each other in time, are distinguished. Geophysical interpretation of the anomalous conditions of the water level time series (with a probability of 0.013) is carried out in comparison to strong earthquakes, technical conditions of observations, and seasonal features of the hydrodynamic regime in the observation well. It is shown that this method of water level data processing can detect short-term anomalies in the hydrogeodynamic regime of a well, significantly supplementing traditional processing of water level data aimed mostly at finding low-frequency trends in water level changes. This method can be applied in geophysical monitoring and prediction of earthquakes from online processing of water level data in wells.

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Section: Technical Conditions Of Observations and Initial Datamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Statistical Analysis of Precision Water Level Data from Observations in a Seismoactive Region: Case Study of the YuZ-5 Well, Kamchatka

2019

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“…Ранее эффекты длительного понижения уровня наблюдались в этой скважине дважды: 1 -после Кроноцкого землетрясения 05.12.1997 г., M w =7.8, d e =200 км, уровень понижался в течение трех меся-цев с амплитудой 1 м [Boldina, Kopylova, 2010;Kopylova, 2006] и 2 -после землетрясения 28.02.2013 г., M w =6.8, d e =260 км уровень понижался с амплитудой 28 см в течение 1.5 мес. [Boldina, Kopylova, 2013].…”

Section: Fig 4 Comparison Between the Water Level Increase Inunclassified

“…рис. 2) вследствие локального улучшения фильтрационных свойств водовмещающих пород при сейсмических сотрясениях и может описываться математической моделью удаленного точечного источника падения напора [Boldina, Kopylova, 2010, 2013Brodsky et al, 2003]:…”

Section: Fig 4 Comparison Between the Water Level Increase Inunclassified

“…Отметим, что результаты моделирования понижений уровня воды после Кроноцкого землетрясения и землетрясения 28.02.2013 г. с использованием (3) согласуются с представленными выше результатами в части определения расстояния до источника падения напора. Во всех случаях эти величины оказались одинаковыми (R=450 м) [Boldina, Kopylova, 2010, 2013. Это может указывать на то, что на расстоянии порядка 450 м от скважины расположен геологический объект, например разломная зона или другой вид гидрогеологического «окна», водопроницаемость которого может резко увеличиваться при сейсмических сотрясениях, достигающих 5 баллов и более по шкале MSK-64.…”

Section: Fig 4 Comparison Between the Water Level Increase Inunclassified

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EFFECTS OF THE JANUARY 30, 2016, Mw=7.2 ZHUPANOVSKY EARTHQUAKE ON THE WATER LEVEL VARIATIONS IN WELLS YUZ-5 AND E-1 IN KAMCHATKA

Болдина¹,

Копылова²

2017

Geodin. tektonofiz.

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This paper describes the water level variations in wells YuZ-5 and E-1 in Kamchatka during the Zhupanovsky earthquake that occurred on January 30, 2016 (Mw=7.2, Н=180 km). The distances from the Zhupanovsky earthquake epicenter to wells E-1 and YuZ-5 were 70 and 80 km, respectively. In well YuZ-5, the water level raised by 9.4 cm during 45 minutes after the seismic wave arrival. This effect was caused by a combination of a co-seismic rise in the water level due to the volumetric compression of the water-bearing rocks during fracturing in the earthquake source and an impulse increase in the fluid pressure near the wellbore during the seismic shocks. We estimated the amplitude of the coseismic water level increase (h=7.3 cm) and the strain value resulting from the volumetric compression of the water-bearing rocks, which is consistent with the estimated value of the coseismic volumetric deformation in the area of the well at the depth of 500m: D1 =-4.510-8. This estimation was based on the model of the dislocation source in the homogeneous isotropic elastic half-space with the parameters of the Zhupanovsky earthquake focal mechanism. After the earthquake, the water level dropped for three months at an amplitude of about ~40 cm. In order to estimate the radius of the well sensitivity to the pressure drop source, we used the model of water level lowering that followed the pressure drop in the aquifer at a distance to the well as a result of the improved filtration properties of the water-bearing rocks after the seismic shocks. The estimated radius of the well sensitivity, R is 450 m. For 3.5 months before the Zhupanovsky earthquake, ~20 cm increase in the water level was observed, which is anomalous in comparison with the average seasonal variations of the water level, as shown by the long-term observations. In our opinion, such a rise in the water level occurred in the process of the earthquake preparation, and can thus be viewed as its precursor. In well E-1, a sequence of water level changes manifested a hydrogeodynamic precursor: the water level dropped at an increased rate for 21 days before the earthquake, and raised at an amplitude of 3.7 cm during one month after the earthquake. The hydrogeodynamic precursor detected in real time gave grounds for forecasting a highly probable strong earthquake at a distance of up to 350 km from wells E-1 within a month. This forecast was reported to the Kamchatka Branch of the Russian Expert Council (KB REC) on January 21, 2016. The Zhupanovsky earthquake occurred on January 30, 2016, and its magnitude, time and location correlated with the prediction. The case of this earthquake shows that the Kamchatka Branch of the Federal Research Center 'Geophysical Survey of RAS' has the system of water level observations and data processing, which is capable of diagnosing (close to real time and retrospectively) different types of hydrogeoseismic variations in the water level in wells in case of strong seismic events, and detecting the hydrogeodynamic precursors of strong earthquakes.

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Regional geodynamic monitoring system for ensuring safety in geological and exploratory production of oil and gas

Vartanyan¹

2010

Izv. Atmos. Ocean. Phys.

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The possibility of estimating the coseismic deformation from water level observations in wells

Cited by 9 publications

References 7 publications

Statistical Analysis of Precision Water Level Data from Observations in a Seismoactive Region: Case Study of the YuZ-5 Well, Kamchatka

Statistical Analysis of Precision Water Level Data from Observations in a Seismoactive Region: Case Study of the YuZ-5 Well, Kamchatka

EFFECTS OF THE JANUARY 30, 2016, Mw=7.2 ZHUPANOVSKY EARTHQUAKE ON THE WATER LEVEL VARIATIONS IN WELLS YUZ-5 AND E-1 IN KAMCHATKA

Regional geodynamic monitoring system for ensuring safety in geological and exploratory production of oil and gas

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