The Response of Water Level in Well YUZ-5, Kamchatka to the Magnitude 9.3,Sumatra-Andaman Earthquake of December 26, 2004

Forced and free oscillations of water level were recorded in well YuZ-5, Kamchatka due to the passage of seismic waves from the Sumatra-Andaman earthquake of December 26, 2004, Mw = 9.3, hypocentral distance 8250 km. The greatest amplitude of water level oscillations, at least 5 cm, was observed during the onset of seismic surface waves with a typical period of 20–50 s. The total duration of the forced and free water-level oscillations was about ten hours. The available theoretical models that describe oscillations were used to estimate the transmissivity of the groundwater reservoir. A hypothesis was proposed to explain a temporary increase in reservoir transmissivity during the passage of seismic waves by invoking defective structure of the crack-pore space and a sharp increase in host rock permeability

Seismo-Hydrogeodynamic Effects in Groundwater Pressure Changes: A Case Study of the YuZ-5 Well on the Kamchatka Peninsula

Seismo-hydrogeodynamic effects (SHGEs) in groundwater level (pressure) variations in a range of periods from minutes to hours and days during local and teleseismic earthquakes were considered based on the data of precision observations in a deep piezometric well located in a seismically active region. With the use of the tidal analysis and frequency dependence of the barometric response of the water level, a static confined response of groundwater pressure in a range of periods from hours to the first tens of days was established. The annual water level trend was characterized by the seasonal function of a hydrostatic head change in the well. In the groundwater pressure, changes were detected due to several types of seismo-hydrogeodynamic effects: 1—the coseismic fluctuations during the first tens of seconds and minutes after the arrival of seismic waves from the earthquakes with magnitudes of 5.3–9.1 at epicentral distances of 80–700 km; 2—the supposed hydrogeodynamic precursors of the two strongest events; 3—the four types of variations under the vibration impact of seismic waves from Mw = 6.8–9.1 earthquakes at epicentral distances of 80–14,600 km. The dependence of the distinguished types of SHGEs on the earthquake parameters, the intensity of the seismic impact in the well area and the amplitude-frequency composition of seismic waves were considered

Estimation of Deformational Properties of a Stratum-Borehole System Based on Analysis of Barometric and Tidal Responses of the Water Level in a Borehole

Statically isolated conditions in the stratum–borehole hydrogeological system under consideration at periods of ≥ 3 h are established on the basis of the investigation of barometric and tidal responses of the water level in a borehole located in the territory of the Mikhnevo Geophysical Observatory, Institute of Geosphere Dynamics, Russian Academy of Sciences. The barometric effectiveness, tidal sensitivity of the water level, elastic parameters, and porosity of water-bearing rocks are estimated. A model of the inertial character of the water exchange in the stratum–borehole system is constructed depending on the period of variations with allowance for the borehole design, as well as the water transmissibility and elastic capacity of the aquifer. The results of modeling are in compliance with the dependence of the amplitude transfer function from variations in the atmospheric pressure to variations in the water level. The results of processing the data of high-precision measurements made it possible to refine the transmissibility of the aquifer obtained from the data of experimental filtration works

Variability in the Statistical Properties of Continuous Seismic Records on a Network of Stations and Strong Earthquakes: A Case Study from the Kamchatka Peninsula, 2011–2021

A study of spatiotemporal variability and synchronization effects in continuous seismic records (seismic noise) on a network of 21 broadband seismic stations on the Kamchatka Peninsula was carried out in connection with the occurrence of strong earthquakes, М = 7.2–8.3. Data of 1‐min registrations of the vertical movements velocity Earth’s surface were used for constructing time series of daily values of the generalized Hurst exponent α*, singularity spectrum support width Δα, wavelet‐based spectral exponent β, and minimum normalized entropy of squared orthogonal wavelet coefficients En for all stations during the observation period 2011–2021. Averaged maps and time‐frequency diagrams of the spectral measure of four noise parameters’ coherent behavior were constructed using data from the entire network of stations and by groups of stations taking into account network configuration, volcanic activity and coastal sea waves. Based on the distribution maps of noise parameters, it was found that strong earthquakes arose near extensive areas of the minimum values of α*, Δα, β, and the En maximum values advance manifestation during several years. The time‐frequency diagrams revealed increased amplitudes of the spectral measure of the coherent behavior of the 4‐dimensional time series (synchronization effects) before three earthquakes with Мw = 7.5–8.3 over months to about one year according to observations from the entire network of stations, as well as according to data obtained at groups of continental and non‐volcanic stations. A less‐pronounced manifestation of coherence effects diagrams plotted from data obtained at coastal and volcanic groups of stations and is apparently associated with the noisiness in seismic records caused by coastal waves and signals of modern volcanic activity. The considered synchronization effects correspond to the author’s conceptual model of seismic noise behavior in preparation of strong earthquakes and data from other regions and can also be useful for medium‐term estimates of the place and time of seismic events with Mw ≥ 7.5 in the Kamchatka

Hydrogeoseismological Research in Kamchatka: 1977–2017

This paper is concerned with the main stages in the setting-up and technical development of a system specializing in physical and chemical parameters of groundwater at a network of wells and springs in the Petropavlovsk Geodynamic Test Area, Kamchatka. The focus is on a description of hydrogeochemical and hydrogeodynamic precursors to Kamchatka earthquakes (Мw = 6.6–7.8) that occur a few weeks to a few months before a seismic event, manifesting themselves in anomalous changes in chemical composition and groundwater level. The precursors are discussed in application to their use at specialized councils on earthquake prediction. It is shown that the system of automated observation of groundwater parameters at wells as developed at the Kamchatka Branch of the Geophysical Survey of the Russian Academy of Sciences (KB GS RAS) is capable of identifying hydrogeodynamic precursors of water level in near real time and of providing,in some particular cases, quantitative estimates of pre-seismic and coseismic of deformation in water-saturated rocks. This can be useful in geophysical monitoring and intermediate-term prediction of strong earthquakes for the Kamchatka region